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Translational studies in Zellweger spectrum disorders
Berendse, K.
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2016
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Berendse, K. (2016). Translational studies in Zellweger spectrum disorders.
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Translational studies in
Zellweger spectrum
disorders
Translational studies in Zellweger spectrum disorders Kevin Berendse
Thesis, University of Amsterdam, Amsterdam ISBN: 978-94-028-0292-4
Cover: Joo Yeon Engelen – Lee
Lay-out: Rianne Wieringa, www.persoonlijkproefschrift.nl Printed by Ipskamp Drukker B.V., www.proefschriften.net Copyright © 2016 Kevin Berendse, The Netherlands
All right reserved. No part of this thesis may be reproduced, stored in a retrieval system or transmitted in any way of by any means without prior permission of the author
Translational studies in
Zellweger spectrum
disorders
ACADEMISCH PROEFSCHRIFT
ter verkrijging van de graad van doctor aan de Universiteit van Amsterdam op gezag van de Rector Magnificus
prof. dr. ir. K.I.J. Maex
ten overstaan van een door het College voor Promoties ingestelde commissie,
in het openbaar te verdedigen in de Agnietenkapel op donderdag 20 oktober 2016, te 14:00 uur
door Kevin Berendse geboren te West Maas en Waal
Promotiecommissie
Promotores: Prof. dr. B.T. Poll-The Universiteit van Amsterdam Prof. dr. R.J.A. Wanders Universiteit van Amsterdam
Copromotores: Dr. M. Engelen Universiteit van Amsterdam Prof. dr. H.R. Waterham Universiteit van Amsterdam
Overige leden: Prof. dr. M. Baes Katholieke Universiteit Leuven Prof. dr. A.K. Groen Universiteit van Amsterdam Prof. dr. H.S. Heymans Universiteit van Amsterdam
Dr. S. Kemp Universiteit van Amsterdam
Prof. dr. F.A. Wijburg Universiteit van Amsterdam Prof. dr. M. Willemsen Radboud Universiteit Nijmegen
Table of contents
Part I
Introduction
Chapter 1 General introduction
Chapter 2 Zellweger spectrum disorders: clinical overview and management approach Orphanet journal of Rare Diseases (2015) 10:151
Part II
Laboratory studies
Chapter 3 Arginine improves peroxisome functioning in cells from patients with a mild peroxisome biogenesis disorder
Orphanet Journal of Rare Diseases (2013) 8:138
Chapter 4 The hypomorphic Pex1-G844D mouse model: a model to study hepatic disease in mild Zellweger spectrum disorders
In preparation for submission
Part III
Clinical trials
Chapter 5 Cholic acid therapy in Zellweger spectrum disorders
Accepted for publication in Journal of Inherited Metabolic Disease
Part IV
Extension of the clinical phenotype
Chapter 6 Zellweger spectrum disorders: clinical manifestations in patients surviving into adulthood
Journal of Inherited Metabolic Disease (2016) 39:93-106
Chapter 7 High prevalence of primary adrenal insufficiency in Zellweger spectrum disorders
Orphanet Journal of Rare Diseases (2014) 9:133
Part V
Summary and general discussion
Chapter 8 Summary, general discussion, future research and implications for
clinical practice
Part VI
Nederlandse samenvatting
Chapter 9 Samenvatting in het Nederlands en beschouwing
Appendix
Authors’ contributions and affiliationsCurriculum Vitae PhD portfolio Acknowledgements / Dankwoord Axels stofwisselingszieke Abbreviations
The work described in this thesis was carried out at the Department of Paediatric Neurology and the laboratory Genetic Metabolic Diseases,
Departments of Clinical Chemistry and Paediatrics, Academic Medical Centre, University of Amsterdam, The Netherlands. The research was funded by a grant of “Stichting Metakids”, “Stichting Steun Emma Kinderziekenhuis” and partly supported by “Hersenstichting”, “Koninklijke Nederlandse Akademie van Wetenschappen” and “Axel Foundation”, The Netherlands.
9 33 59 77 107 129 157 171 183 192 196 197 200 205 219
Chapter 1
1
10 11
Chapter 1 Introduction
Peroxisomes
Peroxisomes are multipurpose organelles surrounded by a membrane containing different transport systems that control in- and efflux of metabolites, are present in almost all eukaryotic cells 1 and are involved in multiple different metabolic
pathways, both catabolic and anabolic 2. The name of the organelle originates
from the description by De Duve and Baudhuin 3, after Rhodin first described the
discovery of a new organelle in mouse kidney cells in 1954 4. In 1966, De Duve
and Baudhuin were the first to describe the presence of catalase and hydrogen peroxide generating enzymes in specific microbodies and therefore named these organelles “peroxisomes”. In humans, peroxisomes are found in every cell, except red blood cells. Peroxisomes are approximately 1µm in width and have a half-life of approximately 2 days in cultured mammalian cells 5. The number of peroxisomes
varies considerably among species and in different cell types, and also depends on the developmental stage and environmental conditions. Peroxisomes adapt to metabolic needs as they can proliferate and multiply or be degraded in response to various stimuli 67. Because this thesis only comprises research in humans and mice,
yeast peroxisomes will not be discussed in detail, although yeast is an excellent model to study more fundamental aspects of peroxisomal function. For a detailed review see 89.
Peroxisome biogenesis
Peroxins are essential for the biogenesis of normal peroxisomes. There are 14 human peroxins, encoded by 14 different PEX genes 10. These peroxins are involved
in either import of peroxisomal membrane proteins (PMPs, i.e.PEX3, PEX11, PEX16 and PEX19) or import of peroxisomal matrix proteins (i.e.PEX1,PEX2, PEX5, PEX6, PEX7, PEX10, PEX12, PEX13, PEX14, PEX26) (figure 1). Within the PMP import process, PEX3 is located in the peroxisomal membrane and acts as a docking site for PEX19, which is a protein located in the cytosol and responsible for binding PMPs 11. The exact function of PEX16 is unknown, but it has been hypothesized
that it functions as a receptor for PEX19 10. When defects involve these proteins,
peroxisome biogenesis is disturbed and often no peroxisomal remnants can be found in the cell 12.
Transportation of peroxisomal matrix proteins into peroxisomes is mediated by two peroxisomal targeting sequences (i.e. PTS-1 and PTS-2) 1314, which are recognized
by specific cytosolic receptor proteins, being the PEX5 small isoform (PEX5S) for C-terminal tripeptide PTS1 motifs and the PEX5 long form (PEX5L)- PEX7 complex for N-terminal octapeptide PTS2 proteins, respectively 15 16 17 (figure 1). PEX5L
contains 37 additional amino acids that allows it to bind to PEX7, transporting PEX7
to the peroxisomal membrane. Only three proteins are currently known to have a PTS2 signal in humans, i.e. thiolase (for β-oxidation), phytanoyl-CoA 2-hydroxylase (for α-oxidation) and alkyl-dihydroxyacetone-phosphate synthase (involved in the ether lipid synthesis pathway) 2. The import machinery of peroxisomal matrix proteins
consists of the PEX14- PEX13 complex, which is the docking complex for PEX5 and PEX7 1819. Thereafter the targeted proteins are transported across the peroxisomal
membrane via PEX2, PEX10 and PEX12 20. Notably, it was recently reported that
the import of PTS-1 and PTS-2 proteins is performed by distinct pores in yeast 21.
Subsequently, PEX5 and PEX7 are released from the membrane for another import cycle (via mono-ubiquitination) or targeted to the proteasome for degradation (via poly-ubiquitination) 22, so called pexophagy 23. Pexophagy is a process that has
extensively been studied in yeast 24. The PEX1, PEX6 and PEX26 complex releases
PEX5 from the peroxisomal membrane 25. When a defect is located in peroxins
involved in the matrix protein import, remnants of peroxisomes, either missing a group of matrix proteins or without any content (“ peroxisomal ghosts”) can be observed 12. PEX11, which consists of three isoforms, including PEX11α, PEX11β
and PEX11γ, is involved in the elongation and constriction of peroxisomes. It is hypothesized that PEX11α is involved in the proliferation and PEX11β in growth and division of peroxisomes 26. The exact function of these isoforms remains to be
elucidated and will not be discussed further.
In recent years, several theories were proposed regarding the formation/division of peroxisomes, mainly based on research in yeast models 2728. The current view
Peroxisomal lumen Cytosol 7 7 5S 5S 5L 5L pts-1 pts-1 pts-2 pts-2 7 14 13 2 12 10 26 6 1 16 3 PMP 19 PMP 19 PMP Matrix protein import Membrane protein import
1
Chapter 1 Introduction
is that peroxisomes are formed de novo from the endoplasmic reticulum, but they can also be formed from pre-existing peroxisomes via division 6 29. Peroxisomal
division occurs via three different processes, including elongation, constriction and fission. Several proteins, i.e. PEX11, dynamin-like protein 1/dynamin-related protein 1 (DLP1/DRP1) 30, fission 1 (FIS1) 31, mitochondrial fission factor (Mff) 32
and ganglioside-induced differentiation associated protein 1 (GDAP1) 33 have been
discovered to play a role in this process in humans. Notably, all these proteins, except for PEX11, are also involved in the fission of mitochondria.
Several co-factors, substrates and products, such as NADH and ATP are necessary for proper peroxisomal function. Transportation of small solute molecules occurs via the channel forming protein PXMP2 34, whereas transport of large molecules
(i.e. so called “bulky” solutes), but also ATP and cofactors, requires active transport
35. Among others, this active transport is mediated by three ATP-binding cassettes
(ABC) transporters, classified as “subfamily D”; ABCD-1, -2 and -3 36 37. These
transporters have a hydrophobic transmembrane domain and hydrophilic region, and are also known as adrenoleukodystrophy protein 38, adrenoleukodystrophy
related protein 39 and peroxisomal membrane protein 70 40, respectively. Research
in yeast, mice and humans revealed that very-long chain acyl-CoAs are transported via ABCD1 41 42, whereas ABCD2 is believed to play a role in the β-oxidation of
polyunsaturated fatty acids (e.g. DHA), as illustrated by the ABCD2 knockout mice 43. ABCD2 also accepts certain substrates for ABCD1 44. ABCD3 is the most
abundant and mediates the transport of branched-chain acyl-CoAs 45.
Peroxisomal functions
As mentioned before, peroxisomes play an important role in several metabolic processes. Knowledge of many of these processes was gained from the discovery of patients with peroxisomal defects and associated biochemical alterations in plasma, urine and skin fibroblasts. Below, the main peroxisomal metabolic pathways in humans will be described briefly.
Fatty acid α-oxidation
Fatty acids with a methyl group at the third position have to be shortened by one carbon atom via the peroxisomal α-oxidation system to produce 2-methyl fatty acids. Phytanic acid (3,7,11,14-tetramethylhexadecanoic acid) is a typical example of a 3-methyl branched chain fatty acid that is converted into the corresponding 2-methyl fatty acid pristanic acid (2,4,6,10-tetramethylpentadecanoic acid) 46, which
subsequently can be degraded via the peroxisomal β-oxidation system 4748. Before
Fatty acid β-oxidation
Fatty acid β-oxidation (i.e. the removal of the carboxyl end of the fatty acid) is one of the main functions of peroxisomes. Similar to the mitochondrial fatty acid β-oxidation, the oxidation consists of four different steps, including dehydrogenation, subsequent hydration, dehydrogenation and thiolytic cleavage 49. In each cycle, 2 carbon atoms
of different substrates are removed. Because the peroxisomal β-oxidation system cannot degrade fatty acids fully into acetyl-CoA units, the shortened fatty acids are shuttled to the mitochondria for further degradation, which may occur via two different routes including a carnitine dependent route and a free fatty acid route (see 2 for detailed discussion). One of the most abundant omega-3 fatty acids is
docosahexaenoic acid (DHA). DHA is considered to be essential for normal brain and retinal development and function 50 5152. Its precursor tetracosahexanaenoic
acid undergoes one cycle of peroxisomal β-oxidation to form DHA 53. In addition,
the peroxisomal β-oxidation system can handle other substrates such as branched chain fatty acids like pristanic acid and the bile acid intermediates di- and trihydroxycholestanoic acid, long chain dicarboxylic acids, the side chains of eicosanoids and other substrates described below.
Bile acid synthesis
Liver peroxisomes are involved in the production of bile acids. The bile acid intermediates dihydroxycholestanoic acid (DHCA) and trihydroxycholestanoic acid (THCA) undergo one cycle of peroxisomal β-oxidation to form the CoA esters of the primarily bile acids chenodeoxycholic acid (CDCA) and cholic acid (CA), respectively
54. These bile acids are then conjugated to their tauro- or glyco-conjugated forms
by the peroxisomal/cytosolic enzyme bile acid-CoA:amino acid N-acyltransferase (BAAT) 55. Subsequently these bile acids are exported from the peroxisomes into bile
canaliculi to be further excreted into the bile.
Glyoxylate detoxification
Glycolate is consumed via vegetables or formed in the mitochondria after catabolism of hydroxyl proline, derived from meat or endogenous collagen turnover. Glycolate is metabolized to glyoxylate in peroxisomes. The end point of glyoxylate detoxification in liver and kidney, as catalysed by the peroxisomal enzyme alanine-glyoxylate aminotransferase (AGT), is glycine 56. When peroxisomes are absent and
AGT is localized in the cytosol, glyoxylate is oxidized to oxalate by cytosolic lactate dehydrogenase. Oxalate cannot be degraded further in vertebrate species and can readily precipitate as calcium oxalate thus forming insoluble crystals. Because of its insolubility, oxalate will deposit in tissue and body fluids, with detrimental effects on
1
14 15
Chapter 1 Introduction
Ether phospholipids synthesis
Phospholipids are major components of the cell membrane and play an important role in a variety of processes 57 58. Phospholipids have a glycerol or sphingosyl
backbone with a polar or hydrophilic head group and nonpolar or hydrophobic fatty acid side chains 59. The majority of phospholipids have an ester bond at the
sn-1 position of the glycerol backbone. Ether phospholipids, however, have an ether bond at this latter position. In mammals, ether phospholipids usually occur in their plasmalogen form, as characterized by an unsaturated 1-0-alkenyl (vinyl ether) group at the sn-1 position. Plasmalogens are found in myelin, heart muscle, erythrocytes and retina 60. Formation of this characteristic ether bond, requires the
obligatory participation of peroxisomes by virtue of the fact that the two enzymes dihydroxyacetonephosphate transferase (DHAPAT) and alkylglycerone phosphate synthase (AGPS) are strictly peroxisomal enzymes. The additional steps for full synthesis of plasmalogens are performed in the endoplasmic reticulum 60.
Other peroxisomal functions
Other metabolic processes in which peroxisomes play a role include: cellular redox metabolism, with pro-oxidant enzymes (FAD-linked oxidases) and the anti-oxidant enzymes catalase and Cu/Zn-superoxide dismutase61. Other functions of
peroxisomes include: the oxidation of L-pipecolic acid and D-amino acids, fatty acid chain elongations and the oxidation of polyamines, although these are all (minor) peroxisomal processes. For a detailed review see 2.
Interplay with other organelles
Peroxisomes are known to interact with different organelles 62. For example,
because peroxisomes cannot degrade fatty acids to completion, due to the lack of a respiratory chain, the products of peroxisomal β-oxidation have to be shuttled to mitochondria for full oxidation to CO2 and H2O 2. Moreover, peroxisomes and
mitochondria interplay in the lipid homeostasis, the production and scavenging of reactive oxygen species, maintenance of redox states, thermogenesis and they share similar proteins for division and fission, which will not be discussed in detail 63 64 65. An
example is the fission protein DLP1. When defective it results in both a peroxisomal and mitochondrial fission defect with devastating results on clinical phenotype 66.
There are also enzymes that are located in both mitochondria and peroxisomes such as 3-hydroxy-3-methylglutaryl-CoA lyase 67 and alpha- methylacyl-CoA racemase
(AMACR) 68. It is important to note that since the discovery of peroxisomal diseases,
concomitant mitochondrial alterations and/or dysfunction have also been reported
69 70 71.
Peroxisomal disorders
After the initial discovery of peroxisomes in 1954, Goldfischer was the first to associate disease with peroxisomal dysfunction/absence in 1973 69. Since 1973,
multiple inherited metabolic diseases of varying extent, related to peroxisomal dysfunction, were discovered. The peroxisomal disorders can be grouped into two different classes based on the underlying defect in (1) the biogenesis of peroxisomes or (2) defects in single peroxisomal enzymes (table 1).
Peroxisome biogenesis disorders
The group of peroxisome biogenesis disorders (PBDs) is comprised of two main entities, including the Zellweger spectrum disorders (ZSDs) and rhizomelic chondrodysplasia punctata (RCDP, type 1 and 5). Other PBDs include defects in the genes for peroxisomal fission, i.e. mutations in DLP1 66, MFF 72, GDAP1 33 and PEX11β 73. Details about ZSDs will be described in Chapter 2. Briefly, the
ZSD are characterized by a spectrum of disease severity ranging from the very mild Heimler syndrome 74 and relatively mild infantile Refsum disease (IRD) 75 to
neonatal adrenoleukodystrophy (NALD) 76 and the most severe phenotype, classical
Zellweger syndrome (ZS) 77. As a result of peroxisomal dysfunction of varying extent,
several biochemical markers can be measured in plasma, urine and erythrocytes, including among others elevated levels of very-long chain fatty acids (VLCFAs) and bile acid intermediates DHCA and THCA.
The pathology within the RCDP spectrum is due to defects in the plasmalogen synthesis, leading to reduced levels of plasmalogens. Clinically these patients have cataract, skeletal dysplasia (i.e. shortening of proximal long bones, rhizomelia) and calcification of cartilage (chondrodysplasia punctata) on X-ray 78. The life expectancy
is usually short 79. However, milder phenotypes are also described 80. RCDP 1 is
caused by mutations in PEX7 and is the most common form of RCDP 80. RCPD
type 5 was recently added to the RCDP spectrum and results from a mutation in
PEX5L 81.
Single peroxisomal enzyme deficiencies
Because this thesis is primarily focused on the peroxisome biogenesis disorders, the single peroxisomal enzyme deficiencies will only be described briefly. For a detailed review see 26.
X-linked adrenoleukodystrophy (X-ALD): X-ALD is the peroxisomal disease with the highest prevalence and affects both men and women 82. In males, the first disease
1
Chapter 1 Introduction
Table 1 Classification of peroxisomal disorders
Disorder Gene
Peroxisome biogenesis disorders
Dynamin-like protein 1 (DLP1) deficiency DLP1
Ganglioside-induced differentiation associated protein 1
(GDAP1) deficiency GDAP1
Mitochondrial fission factor (Mff) deficiency MFF Rhizomelic chondrodysplasia punctata type 1 (RCDP1) PEX7
Rhizomelic chondrodysplasia punctata type 5 (RCDP5) PEX5 (long isoform) Zellweger spectrum disorders (ZSDs) PEX1, 2, 3, 5, 6, 10, 11β, 12, 13, 14, 16,
19, 26
Single peroxisomal enzyme deficiencies
70-kDa peroxisomal membrane protein (PMP70)
deficiency ABCD3
α-methylacyl-CoA racemase (AMACR) deficiency AMACR
Acatalasemia CAT
Acyl-CoA oxidase 1 (ACOX1) deficiency ACOX1
Bile acid-CoA:amino acid N-acyltransferase (BAAT)
deficiency BAAT
Classic Refsum disease PHYH/PEX7
D-bifunctional protein (DBP) deficiency HSD17B4
Isolated glycolic aciduria HAO1
Primary hyperoxaluria type I AGXT
Rhizomelic chondrodysplasia punctata type 2 (RCDP2) GNPAT Rhizomelic chondrodysplasia punctata type 3 (RCDP3) AGPS Rhizomelic chondrodysplasia punctata type 4 (RCDP4) FAR1 Sterol carrier protein X (SCPx) deficiency SCP2
progressive cerebral demyelination and/or myelopathy. Female X-ALD carriers develop signs of myelopathy and/or peripheral neuropathy 83. Overall, the symptoms
are progressive with age. The disease is caused by a mutation in the ABCD1 gene
84 and characterised by accumulation of VLCFAs in tissues and plasma. Recently,
X-ALD was implemented in the newborn screening in New York, USA 85 and it
will soon be implemented in The Netherlands for male neonates. Because levels of C26:0-lysophosphatidylcholine (C26:0-lysoPC) in bloodspots are determined for this newborn screening, ZSD patients will also be diagnosed, as they also present with elevated levels of C26:0-lysoPC.
Peroxisomal acyl-CoA oxidase 1 (ACOX1) deficiency is caused by mutations in
the ACOX1 gene 86. Because ACOX1 is involved in the β-oxidation of VLCFAs,
patients present with elevated levels of VLCFAs in plasma and fibroblasts. Clinical presentations range from a fatal, early onset form with hypotonia, frequent seizures, impaired vision and hearing to a late-onset form with cerebellar abnormalities. To date multiple patients with ACOX deficiency have been reported 8788. Proper
diagnosis requires enzyme testing followed by mutation analysis.
2-Methyl-CoA racemase (AMACR) processes fatty acids with a methyl group in the (R)-configuration to the (S)-configuration, making them ready for peroxisomal
β-oxidation. The AMACR enzyme is located in both peroxisomes and mitochondria, and the two forms are produced from the same gene 8968. Patients with AMACR
deficiency accumulate the (R)-configuration of pristanic acid and bile acid intermediates 90. Clinical symptoms include, among others, liver disease, retinopathy,
peripheral neuropathy and epilepsy in old and/or young 90919293.
D-bifunctional protein (DBP) deficiency is caused by a defect in the enzyme catalysing the second and third step of the peroxisomal β-oxidation. Mutations in the
HSD17B4 gene result in DBP deficiency. The clinical phenotype is broad 94 ranging
from patients dying in the first year of life to patients surviving into adolescence, albeit with severe handicaps (Prof. Poll-The, unpublished data). Recently, several adult patients, with only minor clinical symptoms were diagnosed using whole exome sequencing 9596. Because DBP is involved in the β-oxidation of straight chain
VLCFAs as well as branched-chain FAs, patients accumulate VLCFAs, pristanic and bile acid intermediates in plasma. The enzyme activity can be measured in skin fibroblasts, differentiating DBP from ZSD.
Different mutations in the PHYH gene result in Refsum disease 97, leading to a
dysfunctional phytanoyl-CoA 2-hydroxylase, an enzyme involved in the first step of the peroxisomal α-oxidation 98. Furthermore, specific mutations in PEX7 are also
1
18 19
Chapter 1 Introduction
levels in plasma 100. Therefore the therapy for this disease is relatively simple: a
phytanic acid restricted diet. The clinical phenotype is broad ranging from retinitis pigmentosa, deafness, polyneuropathy and anosmia to liver disease 101.
Currently three different types of RCDP, caused by defects in single peroxisomal enzymes, exist. A mutation in the DHAPAT gene results in RCDP type 2 102. RCDP
type 3 is caused by mutations in the alkyl-dihydroxyacetone phosphate synthase gene 103. Specific mutations in fatty acyl-CoA reductase 1 are described to cause a
deficiency in the production of fatty acid alcohols for the plasmalogens biosynthesis
104, which is referred to as RCDP type 4 105. In general, these diseases cannot
be distinguished based on clinical phenotype and patients present with similar symptoms as the RCDP type 1 phenotype 57, except that no rhizomelia appears to
be present in RCDP type 4 despite the very low plasmalogen levels.
Other enzyme deficiencies with divergent clinical phenotypes include; primary hyperoxaluria type I 106, isolated glycolic aciduria 107, sterol carrier protein X (SCPx)
deficiency 108, 70-kDa peroxisomal membrane protein (PMP70) deficiency 45, bile
acid-CoA:amino acid N-acyltransferase (BAAT) deficiency 109 and acatalasemia 110 111, which will not be discussed in detail.
Mouse models
In order to study the pathogenic mechanism of peroxisomal dysfunction and the consequences of different PEX mutations and associated biochemical alterations,
several mouse models have been generated. Because this thesis is aimed at PBDs, mice with defects in single peroxisomal enzymes will not be discussed here. For a detailed review see 112113. The main symptoms of mice with selective inactivation
of peroxisomes in several tissues (e.g. brain and liver); Pex5-alfp 114, Pex5-albumin
115116117, Pex5-Nestin 114118, Pex5-NEX 119120, Pex5-gfap 119, Pex5-Cnp 121122123,
Pex13-Nestin 124, Pex5-AMH 125, Pex5-aP2 126, are summarized in table 2. Mouse
models for PBD, except the RCDP type 1 127, will be introduced briefly. It should be
noted that the majority of mice had a severe phenotype with mice dying soon after birth.
Mice with a defect in PEX2 (global knockout) were created in different backgrounds
(i.e. C57BL/6 and Swiss Webster) 128129. Marked embryonic lethality was reported
in the C57BL/6 background. When pups were born alive, they suffered from growth retardation, hypotonia, impaired feeding and eventually death within 24 hours. Swiss mice, however, sporadically survived for approximately 1-2 weeks.
Biochemically, the most pronounced abnormalities were increased VLCFAs, altered bile acid metabolism and decreased levels of DHA and plasmalogens. Both models resemble the human ZS phenotype.
The PEX5 mouse model (global knockout) was the first mouse model for ZSD and
also mimics the severe ZS phenotype 130. Mice were born with intra-uterine growth
retardation, were severely hypotonic, and died shortly after birth. Biochemically these mice had increased levels of VLCFAs and depletion of plasmalogens.
A mouse model with a defect in PEX10 was created using N-ethyl-N-nitrosourea
(ENU) mutagenesis 131. The majority of mice died within a few hours after birth,
but some mice did survive. These mice were severely growth retarded and had an ataxic gait. Biochemical results, obtained from E18.5 and 2 adult mice, showed significantly increased levels of the bile acid intermediates and low plasmalogens at E18.5.
Two different models were made with a global knockout of PEX11α. In the model generated by Li et al 132, all peroxisomal biomarkers in plasma were normal and
the same is true for the mouse model developed by Weng et al 133. Only a reduced
number of peroxisomes in livers of PEX11α mice were found. When stressed with
fibrates or a high fat diet, the phenotype, such as fatty liver, was more pronounced. Mice with a defect in PEX11β (global knockout) were born in a normal Mendelian ratio but displayed neonatal lethality, hypotonia and growth retardation. Only a minor increase in the hepatic VLCFAs levels and decreased brain plasmalogens were reported 134.
Mice with defective PEX13 (global knockout) presented with severe hypotonia and
growth retardation and died soon after birth. No intra-uterine death was documented. VLCFAs were elevated and plasmalogens were decreased 135.
Similar to our model (see Chapter 4), another group created a mouse model with a homozygous missense mutation in Pex1 136, which is the most common mutation in
ZSD patients 137 and is associated with a relatively mild phenotype 138 with survival
into adulthood (see Chapter 7). Mice with this defect were born in normal Mendelian ratios. Some survived into adulthood, but the majority died of a natural cause before reaching adulthood. All mice were growth retarded. Biochemical abnormalities comprised increased plasma levels of VLCFAs, DHCA and THCA, C26:0-lysoPC in bloodspots and low levels of plasmalogens in bloodspots. Overall, this model represents the milder end of the ZSD spectrum.
1
Chapter 1 Introduction
Cell type with per
oxisomal deficiency Main symptoms/pathology Biochemical abnormalities Remarks -alfp-cr e
Inactivation of hepatocytes during fetal development
Gr
owth r
etar
dation, cholestasis,
steatosis, steatorrhea and mild tremor
Not r
eported
Mitochondrial abnormalities, 80% died within 8 days
-albumin-cr
e
Hepatocytes >1week postnatal
Gr
owth r
etar
dation untill 3
months of age. Hepatomegaly
, steatosis, fibr osis and car cinogenesis C24 BA, glycogen ↓, C 24
BA, phytanic-, pristanic-acid, lactate
↑
Mitochondrial abnormalities, impair
ed de novo lipogenesis, PP AR α activation, perturbed carbohydrate metabolism -Nestin-cr e Neur ons, astr ocytes, oligodendr ocytes
Survival into adulthood. Motor and coor
dination deficits and
cognitive impairment, evolving in lethargy and death befor
e
the age of 6 months. Delays in neocortex and cer
ebellum
formation, impairment in the formation and maintenance of myelin, axonal degeneration
VLCF A ↑, plasmalogens ↓ Astr o- and micr ogliosis, accumulation of lipid dr oplets -NEX-cr e For ebrain pr ojection neur ons No obvious symptoms None -gfap-cr e Astr ocytes, pr ecursor cells of neur
ons and oligodendr
ocytes No obvious symptoms VLCF A ↑, plasmalogens ↓ Accumulation of lipid dr oplets
Overview of the main symptoms/pathology of mice with selective inactivation of per
oxisomes in several tissues
A very long-chain fatty acids
Cell type with per
oxisomal deficiency Main symptoms/pathology Biochemical abnormalities Remarks -Cnp Oligodendr ocytes
Myelin and axonal abnormalities, late-onset progr
essive neur
odegenerative
disease, peripheral neur
opathy with muscle
weakness VLCF A ↑, plasmalogens ↓
91% died within 12 months, r
eactive gliosis and
neur oinflammation, paranodal swellings -nestin-cr e Neur ons, astr ocytes, oligodendr ocytes Gr owth r etar dation, impair ed
reflex and motor behaviour development, abnormal cer
ebellar formation
Plasmalogens
↓
70% died within 5 weeks, mitchondrial dysfunction, oxidative str
ess, glyosis
-AMH-cr
e
Sertoli
Testicular degeneration and infertility
Lipid dr
oplets
White adipose tissue and non-adipogenic tissues, such as chondr
ocytes, myocytes,
neur
ons and osteocytes.
Lower body weight, incr
eased
fat mass, r
educed lipolysis,
impair
ed adr
energic tone which
impacts on muscle function, impair
ed thermogenesis of
skeletal muscle when fasted, degr
ee of insulin r
esistance
Plasmalogens
↓
Part 2
1
22 23
Chapter 1 Introduction
Outline of this thesis
This thesis focusses on translational studies in patients with a ZSD, with the aim to discover and test new treatments and to create a new mouse model to study the pathogenesis of the milder ZSD phenotype in more detail. The first part of the thesis, Chapter 1, briefly introduces peroxisomes, peroxisomal biogenesis and function, diseases associated with peroxisomal dysfunction and lastly existing PBD mouse models are described. The second part of the introduction (Chapter 2) provides insight in the history of ZSDs, different clinical phenotypes, diagnosis, clinical management and therapeutic options. In general, no treatment for ZSDs exists and management is mainly based on supportive therapy.
To accomplish the original goal of the thesis we tested several promising compounds in skin fibroblasts of patients with a mild ZSD. When immunofluorescent staining for the PTS-1 protein catalase is performed, these skin fibroblasts of mild patients with a specific mutation in PEX1, display a mixed population of cells either with
or without import competent peroxisomes, the so called “peroxisomal mosaicism”
139. These skin fibroblasts regain catalase import competent peroxisomes when
cultured at 30°C, resembling healthy control cells lines. In contrast, when cells are cultured at 40°C, all cells lose import competent peroxisomes. One compound (i.e. arginine) was able to (partially) restore peroxisomal function in skin fibroblasts of mild ZSD patients and was tested in more detail. Hence, detailed results of these experiments are described in Chapter 3, of part II laboratory studies. As described in Chapter 1, several mouse models for PBDs have been created. The majority of these models, however, represent the severe end of the ZSD spectrum, whereas only limited data is available on the first mouse model for mild ZSD patients. In Chapter 4, the results of a comprehensive characterisation of our Pex1 mouse model, a model that represents the milder end of the ZSD spectrum, is presented.
Cholic acid, marketed as Cholbam® in the United States, was recently approved by the FDA for treatment in patients with a ZSD under a ‘rare paediatric disease priority review voucher’. Until now, cholic acid therapy has not been studied in a large cohort of ZSD patients and approval was based on case reports only. In Chapter 5, we report the results of the first large clinical trial of nine months cholic acid supplementation in 19 patients with a ZSD. Briefly, our results indicate that cholic acid does suppress the formation of bile acids in the majority of patients but it can be harmful for patients suffering from severe liver disease.
ZSDs are generally associated with the severe classical ZS phenotype with patients presenting symptoms such as hypotonia, prolonged jaundice, severe cognitive impairment and death within the first year of life. In Chapter 6, part IV, we focus on extension of the clinical phenotype with some important implications for diagnostics
and general knowledge for all those involved in the care of ZSD patients. We describe the clinical phenotype of patients with a ZSD surviving into adulthood, and present age specific symptoms such as peripheral neuropathy with or without pyramidal signs. Moreover, we show that some patients with prolonged survival present an insidiously progressive disease course, despite normalization of biomarkers for peroxisomal disease measured in plasma and erythrocytes. The disease should be considered as a slowly progressive disease with a subgroup of patients surviving into adulthood and not solely as a devastating paediatric disease with death within the first years of life. In addition, recent years many patients were extensively examined during several visits at our outpatient clinic. During these visits we noted that a subgroup of patients developed adrenal insufficiency. Therefore we started a cohort study to determine the prevalence of adrenal insufficiency in (mild) ZSD. The results of this study are described in Chapter 7. Finally, all findings are discussed and future prospectives are provided in Chapter 8.
1
Chapter 1 Introduction
References
1. Gabaldón, T. Peroxisome diversity and evolution. Philos. Trans. R. Soc. Lond. B. Biol. Sci.
365, 765–73 (2010).
2. Wanders, R. J. A. & Waterham, H. R. Biochemistry of mammalian peroxisomes revisited.
Annu. Rev. Biochem. 75, 295–332 (2006).
3. De Duve, C. & Baudhuin, P. Peroxisomes (microbodies and related particles). Physiol. Rev. 46,
323–57 (1966).
4. Rhodin, J. Correlation of ultrastructural organization and function in normal and experimentally changed proximal convoluted tubule cells of the mouse kidney [Ph.D. thesis]. (Aktiebolaget, Godvil, Stockholm, Sweden, 1954).
5. Huybrechts, S. J.,Van Veldhoven, P. P.,Brees, C.,Mannaerts, G. P.,Los, G. V & Fransen, M. Peroxisome dynamics in cultured mammalian cells. Traffic 10, 1722–33 (2009).
6. Schrader, M.,Bonekamp, N. A. & Islinger, M. Fission and proliferation of peroxisomes.
Biochim. Biophys. Acta 1822, 1343–57 (2012).
7. Ezaki, J.,Kominami, E. & Ueno, T. Peroxisome degradation in mammals. IUBMB Life 63,
1001–8 (2011).
8. Smith, J. J. & Aitchison, J. D. Peroxisomes take shape. Nat. Rev. Mol. Cell Biol. 14, 803–17
(2013).
9. Fagarasanu, A.,Mast, F. D.,Knoblach, B. & Rachubinski, R. A. Molecular mechanisms of organelle inheritance: lessons from peroxisomes in yeast. Nat. Rev. Mol. Cell Biol. 11, 644–54
(2010).
10. Fujiki, Y.,Okumoto, K.,Mukai, S.,Honsho, M. & Tamura, S. Peroxisome biogenesis in mammalian cells. Front. Physiol. 5, 307 (2014).
11. Pinto, M. P.,Grou, C. P.,Fransen, M.,Sá-Miranda, C. & Azevedo, J. E. The cytosolic domain of PEX3, a protein involved in the biogenesis of peroxisomes, binds membrane lipids. Biochim. Biophys. Acta 1793, 1669–75 (2009).
12. Waterham, H. R. & Ebberink, M. S. Genetics and molecular basis of human peroxisome biogenesis disorders. Biochim. Biophys. Acta - Mol. Basis Dis. (2012).
13. Subramani, S. Targeting of proteins into the peroxisomal matrix. J. Membr. Biol. 125, 99–106
(1992).
14. Lazarow, P. B. The import receptor Pex7p and the PTS2 targeting sequence. Biochim. Biophys. Acta 1763, 1599–604 (2006).
15. Braverman, N.,Dodt, G.,Gould, S. J. & Valle, D. An isoform of pex5p, the human PTS1 receptor, is required for the import of PTS2 proteins into peroxisomes. Hum. Mol. Genet. 7,
1195–205 (1998).
16. Dodt, G.,Warren, D.,Becker, E.,Rehling, P. & Gould, S. J. Domain mapping of human PEX5 reveals functional and structural similarities to Saccharomyces cerevisiae Pex18p and Pex21p. J. Biol. Chem. 276, 41769–81 (2001).
17. Matsumura, T.,Otera, H. & Fujiki, Y. Disruption of the interaction of the longer isoform of Pex5p, Pex5pL, with Pex7p abolishes peroxisome targeting signal type 2 protein import in mammals. Study with a novel Pex5-impaired Chinese hamster ovary cell mutant. J. Biol. Chem. 275, 21715–21 (2000).
18. Dammai, V. & Subramani, S. The human peroxisomal targeting signal receptor, Pex5p, is translocated into the peroxisomal matrix and recycled to the cytosol. Cell 105, 187–96 (2001).
19. Dodt, G. Multiple PEX genes are required for proper subcellular distribution and stability of Pex5p, the PTS1 receptor: evidence that PTS1 protein import is mediated by a cycling receptor. J. Cell Biol. 135, 1763–1774 (1996).
20. Azevedo, J. E.,Costa-Rodrigues, J.,Guimarães, C. P.,Oliveira, M. E. & Sã-Miranda, C. Protein translocation across the peroxisomal membrane. Cell Biochem. Biophys. 41, 451–68 (2004).
21. Montilla-Martinez, M.,Beck, S.,Klümper, J.,Meinecke, M.,Schliebs, W.,Wagner, R. & Erdmann, R. Distinct Pores for Peroxisomal Import of PTS1 and PTS2 Proteins. Cell Rep. 13, 2126–34
22. Grou, C. P.,Carvalho, A. F.,Pinto, M. P.,Alencastre, I. S.,Rodrigues, T. A.,Freitas, M. O.,Francisco, T.,Sá-Miranda, C. & Azevedo, J. E. The peroxisomal protein import machinery--a case report of transient ubiquitination with a new flavor. Cell. Mol. Life Sci. 66, 254–62
(2009).
23. Kim, P. K.,Hailey, D. W.,Mullen, R. T. & Lippincott-Schwartz, J. Ubiquitin signals autophagic degradation of cytosolic proteins and peroxisomes. Proc. Natl. Acad. Sci. U. S. A. 105,
20567–74 (2008).
24. Manjithaya, R.,Nazarko, T. Y.,Farré, J.-C. & Subramani, S. Molecular mechanism and physiological role of pexophagy. FEBS Lett. 584, 1367–73 (2010).
25. Gouveia, A. M.,Guimarães, C. P.,Oliveira, M. E.,Reguenga, C.,Sá-Miranda, C. & Azevedo, J. E. Characterization of the peroxisomal cycling receptor Pex5p import pathway. Adv. Exp. Med. Biol. 544, 219–20 (2003).
26. Waterham, H. R.,Ferdinandusse, S. & Wanders, R. J. A. Human disorders of peroxisome metabolism and biogenesis. Biochim. Biophys. Acta 1863, 922–33 (2016).
27. Hettema, E. H.,Erdmann, R.,van der Klei, I. & Veenhuis, M. Evolving models for peroxisome biogenesis. Curr. Opin. Cell Biol. 29, 25–30 (2014).
28. Tabak, H. F.,Braakman, I. & van der Zand, A. Peroxisome formation and maintenance are dependent on the endoplasmic reticulum. Annu. Rev. Biochem. 82, 723–44 (2013).
29. Fujiki, Y.,Okumoto, K.,Mukai, S.,Honsho, M. & Tamura, S. Peroxisome biogenesis in mammalian cells. Front. Physiol. 5, 307 (2014).
30. Koch, A.,Thiemann, M.,Grabenbauer, M.,Yoon, Y.,McNiven, M. A. & Schrader, M. Dynamin-like protein 1 is involved in peroxisomal fission. J. Biol. Chem. 278, 8597–605 (2003).
31. Koch, A.,Yoon, Y.,Bonekamp, N. A.,McNiven, M. A. & Schrader, M. A role for Fis1 in both mitochondrial and peroxisomal fission in mammalian cells. Mol. Biol. Cell 16, 5077–86 (2005).
32. Gandre-Babbe, S. & van der Bliek, A. M. The novel tail-anchored membrane protein Mff controls mitochondrial and peroxisomal fission in mammalian cells. Mol. Biol. Cell 19, 2402–
12 (2008).
33. Huber, N.,Guimaraes, S.,Schrader, M.,Suter, U. & Niemann, A. Charcot-Marie-Tooth disease-associated mutants of GDAP1 dissociate its roles in peroxisomal and mitochondrial fission.
EMBO Rep. 14, 545–52 (2013).
34. Rokka, A.,Antonenkov, V. D.,Soininen, R.,Immonen, H. L.,Pirilä, P. L.,Bergmann,
U.,Sormunen, R. T.,Weckström, M.,Benz, R. & Hiltunen, J. K. Pxmp2 is a channel-forming protein in Mammalian peroxisomal membrane. PLoS One 4, e5090 (2009).
35. Visser, W. F.,van Roermund, C. W. T.,Ijlst, L.,Waterham, H. R. & Wanders, R. J. A. Metabolite transport across the peroxisomal membrane. Biochem. J. 401, 365–75 (2007).
36. Kemp, S.,Theodoulou, F. L. & Wanders, R. J. A. Mammalian peroxisomal ABC transporters: from endogenous substrates to pathology and clinical significance. Br. J. Pharmacol. 164,
1753–66 (2011).
37. Morita, M. & Imanaka, T. Peroxisomal ABC transporters: Structure, function and role in disease. Biochim. Biophys. Acta 1822, 1387–96 (2012).
38. Mosser, J.,Douar, A. M.,Sarde, C. O.,Kioschis, P.,Feil, R.,Moser, H.,Poustka, A. M.,Mandel, J. L. & Aubourg, P. Putative X-linked adrenoleukodystrophy gene shares unexpected homology with ABC transporters. Nature 361, 726–30 (1993).
39. Holzinger, A.,Kammerer, S.,Berger, J. & Roscher, A. A. cDNA cloning and mRNA expression of the human adrenoleukodystrophy related protein (ALDRP), a peroxisomal ABC transporter.
Biochem. Biophys. Res. Commun. 239, 261–4 (1997).
40. Kamijo, K.,Kamijo, T.,Ueno, I.,Osumi, T. & Hashimoto, T. Nucleotide sequence of the human 70 kDa peroxisomal membrane protein: a member of ATP-binding cassette transporters.
Biochim. Biophys. Acta 1129, 323–7 (1992).
41. Wiesinger, C.,Kunze, M.,Regelsberger, G.,Forss-Petter, S. & Berger, J. Impaired very long-chain acyl-CoA β-oxidation in human X-linked adrenoleukodystrophy fibroblasts is a direct consequence of ABCD1 transporter dysfunction. J. Biol. Chem. 288, 19269–79 (2013).
1
26 27
Chapter 1 Introduction
43. Fourcade, S.,Ruiz, M.,Camps, C.,Schlüter, A.,Houten, S. M.,Mooyer, P. A. W.,Pàmpols, T.,Dacremont, G.,Wanders, R. J. A.,Giròs, M. & Pujol, A. A key role for the peroxisomal ABCD2 transporter in fatty acid homeostasis. Am. J. Physiol. Endocrinol. Metab. 296, E211–
21 (2009).
44. Pujol, A.,Ferrer, I.,Camps, C.,Metzger, E.,Hindelang, C.,Callizot, N.,Ruiz, M.,Pàmpols, T.,Giròs, M. & Mandel, J. L. Functional overlap between ABCD1 (ALD) and ABCD2 (ALDR) transporters: a therapeutic target for X-adrenoleukodystrophy. Hum. Mol. Genet. 13, 2997–
3006 (2004).
45. Ferdinandusse, S.,Jimenez-Sanchez, G.,Koster, J.,Denis, S.,Van Roermund, C. W.,Silva-Zolezzi, I.,Moser, A. B.,Visser, W. F.,Gulluoglu, M.,Durmaz, O.,Demirkol, M.,Waterham, H. R.,Gökcay, G.,Wanders, R. J. A. & Valle, D. A novel bile acid biosynthesis defect due to a deficiency of peroxisomal ABCD3. Hum. Mol. Genet. 24, 361–70 (2015).
46. Verhoeven, N. M. & Jakobs, C. Human metabolism of phytanic acid and pristanic acid. Prog. Lipid Res. 40, 453–66 (2001).
47. Wanders, R. J. A.,van Roermund, C. W. T.,Visser, W. F.,Ferdinandusse, S.,Jansen, G. A.,van den Brink, D. M.,Gloerich, J. & Waterham, H. R. Peroxisomal fatty acid alpha- and beta-oxidation in health and disease: new insights. Adv. Exp. Med. Biol. 544, 293–302 (2003).
48. Casteels, M.,Foulon, V.,Mannaerts, G. P. & Van Veldhoven, P. P. Alpha-oxidation of 3-methyl-substituted fatty acids and its thiamine dependence. Eur. J. Biochem. 270, 1619–27 (2003).
49. Wanders, R. J. A.,Vreken, P.,Ferdinandusse, S.,Jansen, G. A.,Waterham, H. R.,van Roermund, C. W. & Van Grunsven, E. G. Peroxisomal fatty acid alpha- and beta-oxidation in humans: enzymology, peroxisomal metabolite transporters and peroxisomal diseases.
Biochem. Soc. Trans. 29, 250–67 (2001).
50. Horrocks, L. A. & Yeo, Y. K. Health benefits of docosahexaenoic acid (DHA). Pharmacol. Res.
40, 211–25 (1999).
51. Birch, E. E.,Hoffman, D. R.,Uauy, R.,Birch, D. G. & Prestidge, C. Visual acuity and the essentiality of docosahexaenoic acid and arachidonic acid in the diet of term infants. Pediatr. Res. 44, 201–9 (1998).
52. Bazinet, R. P. & Layé, S. Polyunsaturated fatty acids and their metabolites in brain function and disease. Nat. Rev. Neurosci. 15, 771–785 (2014).
53. Ferdinandusse, S.,Denis, S.,Mooijer, P. a,Zhang, Z.,Reddy, J. K.,Spector, a a & Wanders, R. J. Identification of the peroxisomal beta-oxidation enzymes involved in the biosynthesis of docosahexaenoic acid. J. Lipid Res. 42, 1987–95 (2001).
54. Ferdinandusse, S. & Houten, S. M. Peroxisomes and bile acid biosynthesis. Biochim. Biophys. Acta 1763, 1427–40 (2006).
55. Pircher, P. C.,Kitto, J. L.,Petrowski, M. L.,Tangirala, R. K.,Bischoff, E. D.,Schulman, I. G. & Westin, S. K. Farnesoid X receptor regulates bile acid-amino acid conjugation. J. Biol. Chem.
278, 27703–11 (2003).
56. Salido, E.,Pey, A. L.,Rodriguez, R. & Lorenzo, V. Primary hyperoxalurias: disorders of glyoxylate detoxification. Biochim. Biophys. Acta 1822, 1453–64 (2012).
57. Braverman, N. E. & Moser, A. B. Functions of plasmalogen lipids in health and disease.
Biochim. Biophys. Acta 1822, 1442–52 (2012).
58. Zoeller, R. A.,Lake, A. C.,Nagan, N.,Gaposchkin, D. P.,Legner, M. A. & Lieberthal, W. Plasmalogens as endogenous antioxidants: somatic cell mutants reveal the importance of the vinyl ether. Biochem. J. 338 ( Pt 3, 769–76 (1999).
59. Akoh, C. C. & Min, D. B. in Food Lipids: Chemistry, Nutrition, and Biotechnology, Third Edition, 39–55 (2008).
60. Brites, P.,Waterham, H. R. & Wanders, R. J. A. Functions and biosynthesis of plasmalogens in health and disease. Biochim. Biophys. Acta 1636, 219–31 (2004).
61. Fransen, M.,Nordgren, M.,Wang, B. & Apanasets, O. Role of peroxisomes in ROS/RNS-metabolism: implications for human disease. Biochim. Biophys. Acta 1822, 1363–73 (2012).
62. Wanders, R. J. A. Peroxisomes in human health and disease: metabolic pathways, metabolite transport, interplay with other organelles and signal transduction. Subcell. Biochem. 69,
23–44 (2013).
63. Schrader, M. & Yoon, Y. Mitochondria and peroxisomes: are the ‘big brother’ and the ‘little sister’ closer than assumed? Bioessays 29, 1105–14 (2007).
64. Lismont, C.,Nordgren, M.,Van Veldhoven, P. P. & Fransen, M. Redox interplay between mitochondria and peroxisomes. Front. cell Dev. Biol. 3, 35 (2015).
65. Demarquoy, J. & Le Borgne, F. Crosstalk between mitochondria and peroxisomes. World J. Biol. Chem. 6, 301–9 (2015).
66. Waterham, H. R.,Koster, J.,van Roermund, C. W. T.,Mooyer, P. a W.,Wanders, R. J. A. & Leonard, J. V. A lethal defect of mitochondrial and peroxisomal fission. N. Engl. J. Med. 356,
1736–41 (2007).
67. Ashmarina, L. I.,Robert, M. F.,Elsliger, M. A. & Mitchell, G. A. Characterization of the hydroxymethylglutaryl-CoA lyase precursor, a protein targeted to peroxisomes and mitochondria. Biochem. J. 315, 71–75 (1996).
68. Schmitz, W.,Albers, C.,Fingerhut, R. & Conzelmann, E. Purification and Characterization of an alpha-Methylacyl-CoA Racemase from Human Liver. Eur. J. Biochem. 231, 815–822 (1995).
69. Goldfischer, S.,Moore, C. L.,Johnson, A. B.,Spiro, A. J.,Valsamis, M. P.,Wisniewski, H. K.,Ritch, R. H.,Norton, W. T.,Rapin, I. & Gartner, L. M. Peroxisomal and Mitochondrial Defects in the Cerebro-Hepato-Renal Syndrome. Science. 182, 62–64 (1973).
70. Baumgart, E.,Vanhorebeek, I.,Grabenbauer, M.,Borgers, M.,Declercq, P. E.,Fahimi, H. D. & Baes, M. Mitochondrial alterations caused by defective peroxisomal biogenesis in a mouse model for Zellweger syndrome (PEX5 knockout mouse). Am. J. Pathol. 159, 1477–94 (2001).
71. Salpietro, V.,Phadke, R.,Saggar, A.,Hargreaves, I. P.,Yates, R.,Fokoloros, C.,Mankad, K.,Hertecant, J.,Ruggieri, M.,McCormick, D. & Kinali, M. Zellweger syndrome and secondary mitochondrial myopathy. Eur. J. Pediatr. 174, 557–63 (2015).
72. Shamseldin, H. E.,Alshammari, M.,Al-Sheddi, T.,Salih, M. A.,Alkhalidi, H.,Kentab, A.,Repetto, G. M.,Hashem, M. & Alkuraya, F. S. Genomic analysis of mitochondrial diseases in a consanguineous population reveals novel candidate disease genes. J. Med. Genet. 49, 234–
41 (2012).
73. Ebberink, M. S.,Koster, J.,Visser, G.,Spronsen, F. Van,Stolte-Dijkstra, I.,Smit, G. P. a,Fock, J. M.,Kemp, S.,Wanders, R. J. a & Waterham, H. R. A novel defect of peroxisome division due to a homozygous non-sense mutation in the PEX11β gene. J. Med. Genet. 49, 307–13
(2012).
74. Ratbi, I.,Falkenberg, K. D.,Sommen, M.,Al-Sheqaih, N.,Guaoua, S.,Vandeweyer, G.,Urquhart, J. E.,Chandler, K. E.,Williams, S. G.,Roberts, N. A.,El Alloussi, M.,Black, G. C.,Ferdinandusse, S.,Ramdi, H.,Heimler, A.,Fryer, A.,Lynch, S.-A.,Cooper, N.,Ong, K. R.,Smith, C. E.
L.,Inglehearn, C. F.,Mighell, A. J.,Elcock, C.,Poulter, J. A.,Tischkowitz, M.,Davies, S. J.,Sefiani, A.,Mironov, A. A.,Newman, W. G.,Waterham, H. R. & Van Camp, G. Heimler Syndrome Is Caused by Hypomorphic Mutations in the Peroxisome-Biogenesis Genes PEX1 and PEX6.
Am. J. Hum. Genet. 97, 535–545 (2015).
75. Poll-The, B. T.,Saudubray, J. M.,Ogier, H. a,Odièvre, M.,Scotto, J. M.,Monnens, L.,Govaerts, L. C.,Roels, F.,Cornelis, a & Schutgens, R. B. Infantile Refsum disease: an inherited peroxisomal disorder. Comparison with Zellweger syndrome and neonatal adrenoleukodystrophy. Eur. J. Pediatr. 146, 477–83 (1987).
76. Kelley, R. I.,Datta, N. S.,Dobyns, W. B.,Hajra, A. K.,Moser, A. B.,Noetzel, M. J.,Zackai, E. H. & Moser, H. W. Neonatal adrenoleukodystrophy: new cases, biochemical studies, and differentiation from Zellweger and related peroxisomal polydystrophy syndromes. Am. J. Med. Genet. 23, 869–901 (1986).
77. Bowen, P.,Lee, C. S.,Zellweger, H. & Lindenberg, R. A familial syndrome of multiple congenital defects. Bull. Johns Hopkins Hosp. 114, 402–14 (1964).
78. Braverman, N. E.,D’Agostino, M. D. & Maclean, G. E. Peroxisome biogenesis disorders: Biological, clinical and pathophysiological perspectives. Dev. Disabil. Res. Rev. 17, 187–96
(2013).
79. White, A. L.,Modaff, P.,Holland-Morris, F. & Pauli, R. M. Natural history of rhizomelic chondrodysplasia punctata. Am. J. Med. Genet. A 118A, 332–42 (2003).
1
Chapter 1 Introduction
80. Braverman, N.,Chen, L.,Lin, P.,Obie, C.,Steel, G.,Douglas, P.,Chakraborty, P. K.,Clarke, J. T. R.,Boneh, A.,Moser, A.,Moser, H. & Valle, D. Mutation analysis of PEX7 in 60 probands with rhizomelic chondrodysplasia punctata and functional correlations of genotype with phenotype.
Hum. Mutat. 20, 284–97 (2002).
81. Braverman, N. E.,Moser, A. B. & Steinberg, S. J. Rhizomelic Chondrodysplasia Punctata Type 1. 2001 Nov 16 [Updated 2012 Sep 12]. In Pagon RA, Adam MP, Ardinger HH, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2016 Available at: http://www.ncbi.nlm.nih.gov/books/NBK1270/.
82. Engelen, M.,Kemp, S.,de Visser, M.,van Geel, B. M.,Wanders, R. J. a,Aubourg, P. & Poll-The, B. T. X-linked adrenoleukodystrophy (X-ALD): clinical presentation and guidelines for diagnosis, follow-up and management. Orphanet J. Rare Dis. 7, 51 (2012).
83. Engelen, M.,Barbier, M.,Dijkstra, I. M. E.,Schür, R.,de Bie, R. M. A.,Verhamme, C.,Dijkgraaf, M. G. W.,Aubourg, P. A.,Wanders, R. J. A.,van Geel, B. M.,de Visser, M.,Poll-The, B. T. & Kemp, S. X-linked adrenoleukodystrophy in women: a cross-sectional cohort study. Brain
137, 693–706 (2014).
84. Mosser, J.,Douar, A. M.,Sarde, C. O.,Kioschis, P.,Feil, R.,Moser, H.,Poustka, A. M.,Mandel, J. L. & Aubourg, P. Putative X-linked adrenoleukodystrophy gene shares unexpected homology with ABC transporters. Nature 361, 726–30 (1993).
85. Vogel, B. H.,Bradley, S. E.,Adams, D. J.,D’Aco, K.,Erbe, R. W.,Fong, C.,Iglesias, A.,Kronn, D.,Levy, P.,Morrissey, M.,Orsini, J.,Parton, P.,Pellegrino, J.,Saavedra-Matiz, C. A.,Shur, N.,Wasserstein, M.,Raymond, G. V & Caggana, M. Newborn screening for X-linked adrenoleukodystrophy in New York State: Diagnostic protocol, surveillance protocol and treatment guidelines. Mol. Genet. Metab. 114, 599–603 (2015).
86. Poll-The, B. T.,Roels, F.,Ogier, H.,Scotto, J.,Vamecq, J.,Schutgens, R. B.,Wanders, R. J.,van Roermund, C. W.,van Wijland, M. J. & Schram, A. W. A new peroxisomal disorder with enlarged peroxisomes and a specific deficiency of acyl-CoA oxidase (pseudo-neonatal adrenoleukodystrophy). Am. J. Hum. Genet. 42, 422–34 (1988).
87. Ferdinandusse, S.,Denis, S.,Hogenhout, E. M.,Koster, J.,van Roermund, C. W. T.,IJlst, L.,Moser, A. B.,Wanders, R. J. A. & Waterham, H. R. Clinical, biochemical, and mutational spectrum of peroxisomal acyl-coenzyme A oxidase deficiency. Hum. Mutat. 28, 904–12
(2007).
88. Ferdinandusse, S.,Barker, S.,Lachlan, K.,Duran, M.,Waterham, H. R.,Wanders, R. J. A. & Hammans, S. Adult peroxisomal acyl-coenzyme A oxidase deficiency with cerebellar and brainstem atrophy. J. Neurol. Neurosurg. Psychiatry 81, 310–2 (2010).
89. Ferdinandusse, S.,Denis, S.,IJlst, L.,Dacremont, G.,Waterham, H. R. & Wanders, R. J. Subcellular localization and physiological role of alpha-methylacyl-CoA racemase. J. Lipid Res. 41, 1890–6 (2000).
90. Ferdinandusse, S.,Denis, S.,Clayton, P. T.,Graham, A.,Rees, J. E.,Allen, J. T.,McLean, B. N.,Brown, A. Y.,Vreken, P.,Waterham, H. R. & Wanders, R. J. Mutations in the gene encoding peroxisomal alpha-methylacyl-CoA racemase cause adult-onset sensory motor neuropathy.
Nat. Genet. 24, 188–91 (2000).
91. Clarke, C. E.,Alger, S.,Preece, M. A.,Burdon, M. A.,Chavda, S.,Denis, S.,Ferdinandusse, S. & Wanders, R. J. A. Tremor and deep white matter changes in alpha-methylacyl-CoA racemase deficiency. Neurology 63, 188–9 (2004).
92. Thompson, S. A.,Calvin, J.,Hogg, S.,Ferdinandusse, S.,Wanders, R. J. A. & Barker, R. A. Relapsing encephalopathy in a patient with α-methylacyl-CoA racemase deficiency. BMJ Case Rep. 2009, (2009).
93. Smith, E. H.,Gavrilov, D. K.,Oglesbee, D.,Freeman, W. D.,Vavra, M. W.,Matern, D. & Tortorelli, S. An adult onset case of alpha-methyl-acyl-CoA racemase deficiency. J. Inherit. Metab. Dis.
33 Suppl 3, S349–53 (2010).
94. Ferdinandusse, S.,Denis, S.,Mooyer, P. a W.,Dekker, C.,Duran, M.,Soorani-Lunsing, R. J.,Boltshauser, E.,Macaya, A.,Gärtner, J.,Majoie, C. B. L. M.,Barth, P. G.,Wanders, R. J. A. & Poll-The, B. T. Clinical and biochemical spectrum of D-bifunctional protein deficiency. Ann.
95. Lines, M. A.,Jobling, R.,Brady, L.,Marshall, C. R.,Scherer, S. W.,Rodriguez, A. R.,Lee, L.,Lang, A. E.,Mestre, T. A.,Wanders, R. J. A.,Ferdinandusse, S. & Tarnopolsky, M. A. Peroxisomal D-bifunctional protein deficiency: Three adults diagnosed by whole-exome sequencing.
Neurology (2014).
96. Lieber, D. S.,Hershman, S. G.,Slate, N. G.,Calvo, S. E.,Sims, K. B.,Schmahmann, J. D. & Mootha, V. K. Next generation sequencing with copy number variant detection expands the phenotypic spectrum of HSD17B4-deficiency. BMC Med. Genet. 15, 30 (2014).
97. Jansen, G. A.,Ofman, R.,Ferdinandusse, S.,Ijlst, L.,Muijsers, A. O.,Skjeldal, O. H.,Stokke, O.,Jakobs, C.,Besley, G. T.,Wraith, J. E. & Wanders, R. J. A. Refsum disease is caused by mutations in the phytanoyl-CoA hydroxylase gene. Nat. Genet. 17, 190–3 (1997).
98. Jansen, G. A.,Waterham, H. R. & Wanders, R. J. A. Molecular basis of Refsum disease: sequence variations in phytanoyl-CoA hydroxylase (PHYH) and the PTS2 receptor (PEX7).
Hum. Mutat. 23, 209–18 (2004).
99. Van den Brink, D. M.,Brites, P.,Haasjes, J.,Wierzbicki, A. S.,Mitchell, J.,Lambert-Hamill, M.,de Belleroche, J.,Jansen, G. A.,Waterham, H. R. & Wanders, R. J. A. Identification of PEX7 as the second gene involved in Refsum disease. Adv. Exp. Med. Biol. 544, 69–70 (2003).
100. Wanders, R. J. A.,Komen, J. & Ferdinandusse, S. Phytanic acid metabolism in health and disease. Biochim. Biophys. Acta 1811, 498–507 (2011).
101. Wanders, R. J. A.,Waterham, H. R. & Leroy, B. P. Refsum disease. 2006 Mar 20 [Updated 2015 Jun 11]. In Pagon RA, Adam MP, Ardinger HH, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2016 Available at: http://
www.ncbi.nlm.nih.gov/books/NBK1353/.
102. Ofman, R.,Hettema, E. H.,Hogenhout, E. M.,Caruso, U.,Muijsers, A. O. & Wanders, R. J. A. Acyl-CoA:dihydroxyacetonephosphate acyltransferase: cloning of the human cDNA and resolution of the molecular basis in rhizomelic chondrodysplasia punctata type 2. Hum. Mol. Genet. 7, 847–53 (1998).
103. de Vet, E. C.,Ijlst, L.,Oostheim, W.,Wanders, R. J. A. & van den Bosch, H. Alkyl-dihydroxyacetonephosphate synthase. Fate in peroxisome biogenesis disorders and identification of the point mutation underlying a single enzyme deficiency. J. Biol. Chem. 273,
10296–301 (1998).
104. Buchert, R.,Tawamie, H.,Smith, C.,Uebe, S.,Innes, A. M.,Al Hallak, B.,Ekici, A. B.,Sticht, H.,Schwarze, B.,Lamont, R. E.,Parboosingh, J. S.,Bernier, F. P. & Abou Jamra, R. A peroxisomal disorder of severe intellectual disability, epilepsy, and cataracts due to fatty acyl-CoA reductase 1 deficiency. Am. J. Hum. Genet. 95, 602–10 (2014).
105. Wanders, R. J. A. & Poll-The, B. T. ‘Role of peroxisomes in human lipid metabolism and its importance for neurological development’. Neurosci. Lett. S0304-3940, 00461–9 [Epub ahead
of print] (2015).
106. Danpure, C. J. & Jennings, P. R. Peroxisomal alanine:glyoxylate aminotransferase deficiency in primary hyperoxaluria type I. FEBS Lett. 201, 20–4 (1986).
107. Frishberg, Y.,Zeharia, A.,Lyakhovetsky, R.,Bargal, R. & Belostotsky, R. Mutations in HAO1 encoding glycolate oxidase cause isolated glycolic aciduria. J. Med. Genet. 51, 526–9 (2014).
108. Ferdinandusse, S.,Kostopoulos, P.,Denis, S.,Rusch, H.,Overmars, H.,Dillmann, U.,Reith, W.,Haas, D.,Wanders, R. J. A.,Duran, M. & Marziniak, M. Mutations in the gene encoding peroxisomal sterol carrier protein X (SCPx) cause leukencephalopathy with dystonia and motor neuropathy. Am. J. Hum. Genet. 78, 1046–52 (2006).
109. Hadžić, N.,Bull, L. N.,Clayton, P. T. & Knisely, A. S. Diagnosis in bile acid-CoA: amino acid N-acyltransferase deficiency. World J. Gastroenterol. 18, 3322–6 (2012).
110. Takahara, S. Progressive oral gangrene probably due to lack of catalase in the blood (acatalasaemia); report of nine cases. Lancet 2, 1101–4 (1952).
111. Góth, L. & Nagy, T. Inherited catalase deficiency: is it benign or a factor in various age related disorders? Mutat. Res. 753, 147–54 (2013).
112. Baes, M. & Van Veldhoven, P. P. Mouse models for peroxisome biogenesis defects and β-oxidation enzyme deficiencies. Biochim. Biophys. Acta 1822, 1489–500 (2012).
1
30 31
Chapter 1 Introduction
114. Krysko, O.,Hulshagen, L.,Janssen, A.,Schütz, G.,Klein, R.,De Bruycker, M.,Espeel, M.,Gressens, P. & Baes, M. Neocortical and cerebellar developmental abnormalities in conditions of selective elimination of peroxisomes from brain or from liver. J. Neurosci. Res.
85, 58–72 (2007).
115. Dirkx, R.,Vanhorebeek, I.,Martens, K.,Schad, A.,Grabenbauer, M.,Fahimi, D.,Declercq, P.,Van Veldhoven, P. P. & Baes, M. Absence of peroxisomes in mouse hepatocytes causes mitochondrial and ER abnormalities. Hepatology 41, 868–78 (2005).
116. Peeters, A.,Swinnen, J. V,Van Veldhoven, P. P. & Baes, M. Hepatosteatosis in peroxisome deficient liver despite increased β-oxidation capacity and impaired lipogenesis. Biochimie 93,
1828–38 (2011).
117. Peeters, A.,Fraisl, P.,van den Berg, S.,Ver Loren van Themaat, E.,Van Kampen, A.,Rider, M. H.,Takemori, H.,van Dijk, K. W.,Van Veldhoven, P. P.,Carmeliet, P. & Baes, M. Carbohydrate metabolism is perturbed in peroxisome-deficient hepatocytes due to mitochondrial dysfunction, AMP-activated protein kinase (AMPK) activation, and peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) suppression. J. Biol. Chem. 286, 42162–79
(2011).
118. Hulshagen, L.,Krysko, O.,Bottelbergs, A.,Huyghe, S.,Klein, R.,Van Veldhoven, P. P.,De Deyn, P. P.,D’Hooge, R.,Hartmann, D. & Baes, M. Absence of functional peroxisomes from mouse CNS causes dysmyelination and axon degeneration. J. Neurosci. 28, 4015–27 (2008).
119. Bottelbergs, A.,Verheijden, S.,Hulshagen, L.,Gutmann, D. H.,Goebbels, S.,Nave, K.-A.,Kassmann, C. & Baes, M. Axonal integrity in the absence of functional peroxisomes from projection neurons and astrocytes. Glia 58, 1532–43 (2010).
120. Goebbels, S.,Bormuth, I.,Bode, U.,Hermanson, O.,Schwab, M. H. & Nave, K.-A. Genetic targeting of principal neurons in neocortex and hippocampus of NEX-Cre mice. Genesis 44,
611–21 (2006).
121. Kassmann, C. M.,Lappe-Siefke, C.,Baes, M.,Brügger, B.,Mildner, A.,Werner, H. B.,Natt, O.,Michaelis, T.,Prinz, M.,Frahm, J. & Nave, K.-A. Axonal loss and neuroinflammation caused by peroxisome-deficient oligodendrocytes. Nat. Genet. 39, 969–76 (2007).
122. Kassmann, C. M.,Quintes, S.,Rietdorf, J.,Möbius, W.,Sereda, M. W.,Nientiedt, T.,Saher, G.,Baes, M. & Nave, K.-A. A role for myelin-associated peroxisomes in maintaining paranodal loops and axonal integrity. FEBS Lett. 585, 2205–11 (2011).
123. Ahlemeyer, B.,Neubert, I.,Kovacs, W. J. & Baumgart-Vogt, E. Differential expression of peroxisomal matrix and membrane proteins during postnatal development of mouse brain. J. Comp. Neurol. 505, 1–17 (2007).
124. Müller, C. C.,Nguyen, T. H.,Ahlemeyer, B.,Meshram, M.,Santrampurwala, N.,Cao, S.,Sharp, P.,Fietz, P. B.,Baumgart-Vogt, E. & Crane, D. I. PEX13 deficiency in mouse brain as a model of Zellweger syndrome: abnormal cerebellum formation, reactive gliosis and oxidative stress.
Dis. Model. Mech. 4, 104–19 (2011).
125. Huyghe, S.,Schmalbruch, H.,De Gendt, K.,Verhoeven, G.,Guillou, F.,Van Veldhoven, P. P. & Baes, M. Peroxisomal multifunctional protein 2 is essential for lipid homeostasis in Sertoli cells and male fertility in mice. Endocrinology 147, 2228–36 (2006).
126. Martens, K.,Bottelbergs, A.,Peeters, A.,Jacobs, F.,Espeel, M.,Carmeliet, P.,Van Veldhoven, P. P. & Baes, M. Peroxisome deficient aP2-Pex5 knockout mice display impaired white adipocyte and muscle function concomitant with reduced adrenergic tone. Mol. Genet. Metab. 107, 735–47 (2012).
127. Brites, P.,Motley, A. M.,Gressens, P.,Mooyer, P. a W.,Ploegaert, I.,Everts, V.,Evrard,
P.,Carmeliet, P.,Dewerchin, M.,Schoonjans, L.,Duran, M.,Waterham, H. R.,Wanders, R. J. A. & Baes, M. Impaired neuronal migration and endochondral ossification in Pex7 knockout mice: a model for rhizomelic chondrodysplasia punctata. Hum. Mol. Genet. 12, 2255–67 (2003).
128. Faust, P. L. Abnormal cerebellar histogenesis in PEX2 Zellweger mice reflects multiple neuronal defects induced by peroxisome deficiency. J. Comp. Neurol. 461, 394–413 (2003).
129. Faust, P. L. & Hatten, M. E. Targeted deletion of the PEX2 peroxisome assembly gene in mice provides a model for Zellweger syndrome, a human neuronal migration disorder. J. Cell Biol.
139, 1293–305 (1997).
130. Baes, M.,Gressens, P.,Baumgart, E.,Carmeliet, P.,Casteels, M.,Fransen, M.,Evrard, P.,Fahimi, D.,Declercq, P. E.,Collen, D.,van Veldhoven, P. P. & Mannaerts, G. P. A mouse model for Zellweger syndrome. Nat. Genet. 17, 49–57 (1997).
131. Hanson, M. G.,Fregoso, V. L.,Vrana, J. D.,Tucker, C. L. & Niswander, L. A. Peripheral nervous system defects in a mouse model for peroxisomal biogenesis disorders. Dev. Biol. 395, 84–95
(2014).
132. Li, X.,Baumgart, E.,Dong, G.-X.,Morrell, J. C.,Jimenez-Sanchez, G.,Valle, D.,Smith, K. D. & Gould, S. J. PEX11alpha is required for peroxisome proliferation in response to 4-phenylbutyrate but is dispensable for peroxisome proliferator-activated receptor alpha-mediated peroxisome proliferation. Mol. Cell. Biol. 22, 8226–40 (2002).
133. Weng, H.,Ji, X.,Naito, Y.,Endo, K.,Ma, X.,Takahashi, R.,Shen, C.,Hirokawa, G.,Fukushima, Y. & Iwai, N. Pex11α deficiency impairs peroxisome elongation and division and contributes to nonalcoholic fatty liver in mice. Am. J. Physiol. Endocrinol. Metab. 304, E187–96 (2013).
134. Li, X.,Baumgart, E.,Morrell, J. C.,Valle, D.,Gould, S. J. & Jimenez-sanchez, G. PEX11 beta deficiency is lethal and impairs neuronal migration but does not abrogate peroxisome function. Mol Cell Biol 22, 4358–4365 (2002).
135. Maxwell, M.,Bjorkman, J.,Nguyen, T.,Finnie, J.,Paterson, C.,Tonks, I.,Barbara, C.,Kay, G. F.,Crane, D. I.,Sharp, P. & Paton, B. C. Pex13 inactivation in the mouse disrupts peroxisome biogenesis and leads to a Zellweger syndrome phenotype. Mol Cell Biol 23, 5947–5957
(2003).
136. Hiebler, S.,Masuda, T.,Hacia, J. G.,Moser, A. B.,Faust, P. L.,Liu, A.,Chowdhury, N.,Huang, N.,Lauer, A.,Bennett, J.,Watkins, P. a,Zack, D. J.,Braverman, N. E.,Raymond, G. V & Steinberg, S. J. The Pex1-G844D mouse: a model for mild human Zellweger spectrum disorder. Mol. Genet. Metab. 111, 522–32 (2014).
137. Ebberink, M. S.,Mooijer, P. a W.,Gootjes, J.,Koster, J.,Wanders, R. J. A. & Waterham, H. R. Genetic classification and mutational spectrum of more than 600 patients with a Zellweger syndrome spectrum disorder. Hum. Mutat. 32, 59–69 (2011).
138. Rosewich, H.,Ohlenbusch, a & Gärtner, J. Genetic and clinical aspects of Zellweger spectrum patients with PEX1 mutations. J. Med. Genet. 42, e58 (2005).
139. Imamura, A.,Tamura, S.,Shimozawa, N.,Suzuki, Y.,Zhang, Z.,Tsukamoto, T.,Orii, T.,Kondo, N.,Osumi, T. & Fujiki, Y. Temperature-sensitive mutation in PEX1 moderates the phenotypes of peroxisome deficiency disorders. Hum. Mol. Genet. 7, 2089–94 (1998).
Chapter 2
Zellweger spectrum disorders:
Clinical overview and management approach
Kevin Berendse 1,2 *, Femke CC Klouwer 1,2 *, Sacha Ferdinandusse 2,
Ronald JA Wanders 2, Marc Engelen 1, Bwee Tien Poll-The 1
* Equal contributors
1 Department of Paediatric Neurology, Emma Children’s Hospital/Academic Medical Centre,
University of Amsterdam, Amsterdam, The Netherlands.
2 Laboratory Genetic Metabolic Diseases, Academic Medical Centre, University of
