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Familial hypercholesterolemia. The determination of phenotype
Jansen, A.C.M.
Publication date
2003
Link to publication
Citation for published version (APA):
Jansen, A. C. M. (2003). Familial hypercholesterolemia. The determination of phenotype.
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geneticc variation
AA study in 2000 familial hypercholesterolemia
heterozygotes s
Angeliquee CM Jansen
1, MD; Emily S van Aalst-Cohen
1, MD; Michael WT
Tanck
2,, PhD; Marcel R Fontecha
3, BS; Suzanne Cheng
3, PhD; Joep C
Defesche
1,, PhD, and John JP Kastelein
1, MD, PhD
Departmentss of 'Vascular Medicine and 2Clinical Epidemiology and Biostatistics, Academic Medicall Center, University of Amsterdam, Amsterdam, the Netherlands.
Departmentt of Human Genetics, Roche Molecular Systems, Inc., Alameda, California, USA.
Abstract t
Background dFamiliall hypercholesterolemia (FH) is a common hereditary disorder, characterized by elevated low-density-lipoprotein(LDL)-cholesteroll and by premature cardiovascular disease (CVD). Geneticc variation outside the LDL-receptor gene is presumed to play an important role in thee clinical phenotype of this disorder, in terms of onset and severity of CVD. However, studiess that simultaneously examine polymorphisms in numerous genes do not exist for FH patients. .
Methodss and results
Wee genotyped 2092 FH patients for 65 polymorphisms in 36 candidate genes. During 98.6333 person-years, 692 (33.1 %) patients had at least one cardiovascular event. Multivariate Coxx survival analysis revealed that the G20210A polymorphism in the prothrombin gene wass most strongly associated with a significantly increased CVD risk (GA versus GG; p< 0.0001).. In addition, three other polymorphisms were also associated with increased CVD risk;; Met235Thr in the angiotensinogen gene, Thr347Ser in the apolipoprotein A4 gene andd Gly460Trp in the alpha-adducin gene, whereas conversely, the Ser311Cys substitution inn the paraoxonase-2 gene and the C1100T variant in the apolipoprotein C3 gene related too decreased CVD risk (p<0.05).
Conclusions s
Inn the largest cohort of FH patients studied to date, we identified six polymorphisms in candidatee genes that were related to CVD risk. Our results constitute a step forward in the unravellingg of the hereditary propensity towards CVD in FH and might lead to better risk stratificationn and hence to more tailored therapy in terms of CVD prevention.
Introduction n
Familiall hypercholesterolemia (FH) is a common, hereditary disease, classically characterized byy elevated levels of plasma low-density lipoprotein cholesterol (LDL-C) and premature cardiovascularr disease (CVD).1 Characteristically, the mean age of onset of CVD is between 400 and 45 years in male FH patients and in female FH patients 10 years later.12 Nevertheless, thee phenotypic expression of this disorder, in terms of onset and severity of atherosclerotic vascularr disease, varies to a very large extent.3
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phenotypicc differences. Previous studies have mostly focused on classical CVD risk factors andd the functional variety among LDL-receptor mutations.46 While both indeed do influence thee occurrence of CVD, they can only partially explain the large differences.
Geneticc differences affect susceptibility to disease and whilst premature atherosclerosis cann be linked in rare cases to single-gene disorders, most individuals do not carry such DNA defects.. The 'common disorder, common variant' theory predicts that the largest part of thee variation in susceptibility to prevalent disease in humans is caused by variants that occurr in high frequency in multiple genes.7
Suchh genetic variation must also play an important role in the development of CVD in FH. Thiss is substantiated by the fact that clustering of CVD occurs in FH kindreds.8 In FH, so far, onlyy small case-control studies have been carried out, studying the role of one or only severall polymorphisms. However, it is well known that large studies yield more conservative resultss than smaller studies, prone to over-estimate the risks.9 Unfortunately, large-scale associationn studies involving significant numbers of polymorphisms are lacking in FH. Our objective,, therefore, was to investigate the contribution to CVD risk of polymorphisms in a substantiall number of candidate genes in a large cohort of patients with heterozygous FH.
Methods s
Design n
Thee present investigation was a retrospective, multicenter, cohort study. The central DNA andd Biobank at the Academic Medical Centre contains DNA samples and demographics of moree than 9300 severely hypercholesterolemic patients collected from Lipid Clinics throughoutt the Netherlands. We randomly selected a cohort of 4000 hypercholesterolemic patientss (from 27 different hospitals) out of this database.
Dataa collection
Phenotypicall data, FH diagnostic criteria (see below), risk factors, laboratory parameters
andd CVD endpoints, were acquired by reviewing the patients' records by 13 data collectors. Too ensure data completeness, additional information was sought from general practitioners, patients,, and hospitals that patients had visited formerly. To obtain consistent datasets, qualityy guidelines were implemented. All data collectors underwent extensive training; handbookss with clinical definitions were used and interobserver studies were carried out. Dataa collectors were blinded for DNA genotyping results. The Ethics Institutional Review Boardd of each participating hospital approved the protocol and written informed consent wass obtained from all patients (except deceased patients).
FHH diagnostic criteria
Wee used a combination of established diagnostic criteria to identify patients with FH.u-, a 1 2 Withh regard to the Simon Broome report2, we did not distinguish between definite and possiblee FH, but applied more stringent cut-off LDL-C levels. Male and female FH patients of 188 years and older were included if they met the following criteria: (I) the presence of a documentedd LDL-receptor mutation, or (II) an LDL-C level above the 95th percentile for genderr and age, in combination with (a) the presence of tendon xanthomas in the patient orr in a first-degree relative, or (b) an LDL-C level above the 95th percentile for age and genderr in a first-degree relative, or (c) proven CAD in the patient or in a first-degree relative underr the age of 60 years. Only one index case per family was included.
Classicall risk factors
Malee gender, age, smoking, body mass index and the presence of hypertension and diabetes mellituss were considered classical risk factors. The lifetime consumption of cigarettes was definedd by start and stop dates. Hypertension was defined when the diagnosis had been madee and when anti-hypertensive medication was prescribed, or if three consecutive measurementss of blood pressure were >140 mmHg systolic or > 90 mmHg diastolic. Diabetes mellituss was defined when the diagnosis had been made and medication (insulin or oral anti-diabetics)) was prescribed, or by a fasting plasma glucose of > 6.9 mmol/L.
Laboratoryy parameters
Lipidd levels, as stated in the medical record, were determined in fasting patients not using lipid-loweringg medication for at least 6 weeks. Total cholesterol (TC), high-density lipoprotein cholesteroll (HDL-C) and triglycerides were measured by standard methods. LDL-C was calculatedd with the Friedewaid formula.
Cardiovascularr disease endpoints
Thee occurrence of CVD was the primary outcome of our study and was diagnosed by the presencee of at least one of the following: (I) myocardial infarction, proven by at least two
off the following: (a) classical symptoms (>15 minutes), (b) specific EKG abnormalities, (c) elevatedd cardiac enzymes (> 2x upper limit of normal); (II) percutaneous coronary intervention orr other invasive procedures; (III) coronary artery bypass grafting; (IV) angina pectoris, diagnosedd as classical symptoms in combination with at least one unequivocal result of one off the following; (a) exercise test, (b) nuclear scintigram, (c) dobutamine stress ultrasound, (d)) a more than 70% stenosis on a coronary angiogram; (V) ischemic stroke, demonstrated byy CT- or MRI scan (VI) documented transient ischemic attack; (VII) peripheral arterial bypass graft;; (VIII) peripheral percutaneous transluminal angioplasty or other percutaneous invasive
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withh at least one unequivocal result of one of the following: (a) ankle/arm index<0.9 or (b) aa stenosis (>50%) on an angiogram or duplex scan.
Iff information on CVD did not strictly fulfill the above mentioned criteria the case was presentedd to an independent adjudication committee.
Selectionn of DNA polymorphisms
Wee genotyped 65 polymorphisms in 36 candidate genes that were associated with CVD by theirr contribution to lipid metabolism, blood pressure regulation, coagulation and hemostasis, homocysteinee metabolism, endothelial function, cell adhesion, inflammation or plaque stability. .
Geneticc analyses
Genomicc DNA was extracted from peripheral blood leukocytes by standard procedures. Genotypingg was performed using multiplex PCR- and hybridization-based assays, essentially ass previously described.'3 Samples were blinded for genotyping.
Thee accuracy of genotyping in 500 randomly selected DNA samples was assessed at by re-analysiss of several polymorphisms in different genes (CETP, MTHFR, LPL). Less than 0.5% off discordant results were found.
Statisticall analysis
Differencess between subgroups were tested with chi-square statistics or independent sample t-testt (for triglycerides (skewed distribution) on logtransformed data). To adjust for the effectss of age and gender we used multiple linear or logistic regression.
Coxx proportional hazard regression analysis with forward selection was used to model the associationn of all genetic polymorphisms simultaneously and the occurrence of CVD as a dependentt variable. Follow-up started at birth and ended for each individual at the date of thee first occurrence of established CVD. Patients without CVD were censored at the date of thee last Lipid Clinic visit or at the date of death attributable to other causes. First, each
polymorphismm was assessed individually with the use of an additive, dominant or recessive
geneticc model, respectively. The genetic model with the maximum log-likelihood was selected ass "best fitting" genetic model and entered into the multivariate model. Since polymorphisms mightt express their untoward effects via for example hypertension, diabetes rmellitus, obesity orr dyslipidemia we decided not to introduce these factors as covariables in our models. Instead,, we only added covariates that are independent of the polymorphisms: gender and smokingg (time-dependent). For smoking we implemented a linearly decreasing risk effect forr the three years after cessation.14 To enable comparison of our results with those from earlierr studies, we additionally performed the same Cox regression model with adjustments forr multiple risk factors. The detected hazard ratios were identical and are not shown in the resultss section. A loglikelihood ratio test was used to detect pairwise linkage disequilibrium. Statisticall analyses were performed using SPSS software {version 10.0, Chicago, Illinois). Hazardd ratios with a p-value of less than 0.05 were considered to be suggestively associated; thosee with p-values less than 0.001 were considered statistically significant.
Results s
Uponn reviewing 4000 medical records and application of our diagnostic criteria, 2400 patients weree diagnosed with FH. Among the remaining 1600 patients, the vast majority had other dyslipidemias,, whereas 23 (0.6%) patients were unwilling to participate. Complete genotypes weree obtained in 2092 patients (87,2%). The 308 remaining patients did not differ in terms off CVD or any other characteristic. In our ongoing DNA diagnostic program, the LDL-receptor defectt has been identified in 52.8 % of these patients.
Clinicall characteristics of the 2092 patients are described in table 1. During 98.633 person-years,, 692 (33.1 %) patients had at least one cardiovascular event, including three individuals whoo died from their first documented CVD event. Mean age of onset of CVD was 48.4 years.. Patients with CVD were older, more often males and smokers and had a higher prevalencee of hypertension and diabetes mellitus. More obesity and higher TC levels were alsoo observed among CVD patients, but were not significant after adjustment for age and gender.. LDL-C levels did not differ between CVD and non-CVD patients. HDL-C levels were lowerr (1.14 0.32 vs. 1.24 0.36 mmol/L; p<0.001) and median triglyceride levels higher (1.766 vs. 1.48 mmol/L; p<0.001) in patients with CVD.
Thee 36 genes and 65 polymorphisms examined in the study are presented in table 2. For threee polymorphisms in the CETP gene (Asp442Gly, G to A at +1 and an inserted T at +3 in intronn 14) only homozygous wild-type subjects were found and these were excluded from furtherr analysis.
Multivariatee Cox survival analysis with the 62 polymorphisms simultaneously, adjusted for genderr and smoking, revealed that the G20210A polymorphism in the prothrombin gene
exhibitedd a strong association with a significantly increased risk of CVD (GA versus GG; p< 0.0001)) (table 3). In addition, five other polymorphisms were identified to be associated withh CVD; Met235Thr in the angiotensinogen gene, Thr347Ser in the apolipoprotein (apo) A44 gene and Gly460Trp in the alpha-adducin gene, all with increased risk, and conversely, Ser3111 Cys in the paraoxonase-2 gene and C1100T in the apoC3 gene with decreased risk (p<0.05).. Strong linkage disequilibrium was observed between the polymorphisms C1100T inn apoC3 and Thr347Ser in apoA4 (D'=-0.928).
Thee genotyptc distributions of the polymorphisms are given in table 4.
Tablee 1 . Clinical characteristics of 2092 FH patients w i t h and w i t h o u t ca
Patientt number (%) Malee sex (%)
Agee at first Lipid Clinic visit (years) Agee at tast Lipid Clinic visit (years)
Smoking,, ever (%) Hypertensionn (%) Diabetess mellitus (%) Bodyy mass index (kg/m2)
Totall cholesterol (mmol/L) LDLL cholesterol (mmol/L) HDLL cholesterol (mmol/L) Triglyceridess (mmol/L)
Valuess are given as mean levels aree given as median w i t h the inte
CVDD + 6922 (33.1%) 61.3 3 50.55 ( 11.3) 56.66 ( 11.4) 82.9 9 17.3 3 10.4 4 25.77 ) 9.655 ) 7.411 ) 1.144 ) 1.766 [1.28-2.38] standard deviation, C V D --14000 (66.9%) 42.5 5 42.11 ( 12.6) 46.55 ( 12.8) 70.4 4 6.3 3 3.4 4 24.88 ( 3.6) 9.400 ( 1.87) 7.300 ( 1.82) 1.244 ) 1,488 [1.02-2.09; rdiovascularr c pp value << 0.001 << 0.001 << 0.001 << 0.001 << 0.001 << 0.001 << 0.001 0.02 2 0.3 3 << 0.001 << 0.001 isease e pp value adjusted forage forage andd gender na a na a na a << 0.001 << 0.001 << 0.001 0.1 1 0.05 5 0.4 4 << 0.001 0.001 1
exceptt where given as percentages. Triglycerides rquartilee range between brackets. CVD+
present;; CVD-, cardiovascular disease absent; na, not c densityy lipoprotein.
indicatess card applicable;; LDL, low-density lipop
ovascularr disease rotein;; HDL,
high-Tablee 2. The 65 polymorphisms examined in the Gene e Lipidd metabolism Lipoprotein(a) ) Apolipoproteinn A4 Apolipoproteinn B Apolipoproteinn C3 Apolipoproteinn E [^-adrenergicc receptor Cholesteryll ester transferr protein Hepaticc lipase Loww density lipoprotein receptor r
Lipoproteinn lipase
Paraoxonase e
Paraoxonase-2 2 Peroxisomee proliferator-activatedd receptor gamma2
Polymorphism m C93T T G121A A Thr3475er r Gln360His s Thr71lle e C(-641)A A C(482)T T T{-455)C C C1100T T C3175G(Sstl) ) T3206G G Cys112Arg g Arg158Cys s Trp64Arg g C(-631)A A C(-629)A A He405Val l Asp442Gly y G(+1)A A (+3)TT ins in intron 14 TaqlB B C(480)T T Ncol+/-- in exon 18 T(-93)G G Asp9Asn n Asn291Ser r Ser447Term m Met55Leu u Gln192Arg g Ser31Kys s Proo 12 Ata
Bloodd pressure regulation (part 1)
Dipeptidyl l carboxypeptidasee 1 (== Angiotensin-converting enzyme) )
Angiotensinogen n
Angiotensinn II receptor type 1 Alpha-adducin n
Atriall natriuretic peptide precursorr A Aluu element l/D inn intron 16 Met235Thr r A1166C C Gly460Trp Gly460Trp G664AA (Val7Met) T2238C(Scal) ) study y Gene e Polymorphism m
Bloodd pressure regulation (part 11)
B2-adrenergicc receptor
Epitheliall sodium channel
G-proteinn B3 subunit
Coagulationn and hemostasis
Coagulationn factor II (Prothrombin) ) Coagulationn factor V Coagulationn factor VII
B-fibrinogen n Glycoproteinn la Glycoproteinn Ilia Plasminogen-activatorr inhibitor typee 1 Homocysteinee metabolism
Cystathionee beta synthase
Methylenetetrahydrofolate e reductase e
Endotheliall function
Nitricc oxide synthase type 3
Argg 16Gly Gln27Glu u Trp493Arg g A!a663Thr r C825TT (splice variant) G20210A A Arg506Gln n Arg353Gln n (-323)) 10bp del/ins G(-455)A G(-455)A G873A A Leu33Pro o (-675)) 5G/4G G11053T T Combination n lle278Thrr and 68-bpp insertion C677T T A(-922)G G C(-690)T T G894TT (Glu298Asp)
Celll adhesion, inflammation and plaque stability
E-selectinn (endothelial leukocyte adhesionn molecute-1; ELAM) Intercellularr adhesion molecule-1 Tumorr necrosis factor alfa
Tumorr necrosis factor betaa (lymphotoxin alpha) Metall loproteinase 3 (Stromelysin-I) ) Ser128Arg g Leu554Phe e Gly214Arg g G(-376)A A G(-308)A G(-308)A G(-244)A G(-244)A G{-238)A A Thr26Asn n (-1171)5A/6A A
Tablee 3. Multivariate Cox regression of Gene e Prothrombin n Angiotensinogen n Apolipoproteinn A4 Paraoxonase-2 2 Apolipoproteinn C3 Alpha-adducin n Polymorphism m G20210A A Met235Thr r Thr347Ser r Ser311 ICys C1100T T Gly460Trp p polymorphismss associated w i t h Bestt fitting geneticc model Dominant t Dominant t Recessive e Recessive e Recessive e Dominant t Hazard d Ratio o 2.47 7 1.23 3 1.40 0 0.66 6 0.67 7 1.17 7 cardiovascularr disease 95%% CI 1 . 5 8 - 3 . 8 8 8 1.04-- 1.45 1.011 - 1.95 0.455 - 0.97 0.488 - 0.94 1.002-- 1.38 P P << 0.0001 0.013 3 0.044 4 0.035 5 0.020 0 0.047 7
Tablee 4. Distributions of polymorphisms associé Genee and polymorphism
Prothrombin n Angiotensinogen n Apolipoproteinn A4 Paraoxonase-2 2 Apolipoproteinn C3 Alpha-adducin n G20210A A G/G G G/A A A/A A M e t 2 3 5 t h r r M e t / M e t t Met/Thr r Thr/Thr r Thr347Ser r Thr/Thr r Thr/Ser r Ser/Ser r Ser311Cys s Ser/Ser r Ser/Cys s Cys/Cys s C1100T T c/c c C/T T T/T T Gly460Trp p Gly/Gly y Gly/Trp p Trp/Trp p
tedd w i t h cardiovascular disease
CVDD + percent t 97.1 1 2.9 9 0 0 34.3 3 48.2 2 17.5 5 66.8 8 27.6 6 5.6 6 58.6 6 36.9 9 4.4 4 56.0 0 38.2 2 5.8 8 60.5 5 34.2 2 5.3 3 C V D --percent t 98.4 4 1.6 6 0 0 39.1 1 46.4 4 14.5 5 67.2 2 28.7 7 4.1 1 57.4 4 35.5 5 7.1 1 55.6 6 35.8 8 8.6 6 64.0 0 30.5 5 5.5 5 79 9
Discussion n
Wee investigated the contribution of a significant number of polymorphisms in a large number off candidate genes to CVD risk in FH patients. Strikingly, the G20210A polymorphism of thee prothrombin gene was most strongly related to a significantly increased CVD risk. In addition,, five other polymorphisms were associated with CVD: three with increased risk; Met235Thrr in the angiotensinogen gene, Thr347Ser in the apoA4 gene and Gly460Trp in thee alpha-adducin gene, and in contrast, the Ser311 Cys substitution in the paraoxonase-2 genee and the C11 DOT variant in the apoC3 gene with decreased risk.
Ourr results are in line with earlier findings. The prothrombin mutation G20210A leads to increasedd plasma levels of prothrombin and an excessive risk of venous thrombosis.^ Many studiess have focused on the role of this mutation in arterial disease, mostly with negative results.16177 In contrast, two large studies showed a pronounced effect of this polymorphism onn CVD events in dyslipidemic patients.'319 This finding supports the strong association betweenn G20210A carriership and CVD risk in our FH patients who suffer from severe dyslipidemiaa from birth onwards.
Recently,, the M235T polymorphism of the angiotensinogen gene was associated with increasedd levels of angiotensinogen and a corresponding increase in the risk of hypertension, ass assessed in 45.267 individuals.20 Again, in our FH patients, the combined effect of elevated angiotensinogenn and LDL-C levels might explain the occurrence of CVD.
Wee identified two common variants of the gene cluster ApoA1-C3-A4-A5 to be significantly associatedd with CVD risk (Thr347Ser in apoA4 and C1100T in apoC3). Apolipoproteins play aa central role in lipid metabolism and this cluster of apolipoprotein genes has been identified ass a locus with significant effects on triglyceride levels.2122 Only very recently, the first prospectivee study on genetic variants in this gene cluster and CVD risk in the general populationn was reported.23 Remarkably, in this large study, exactly the same t w o polymorphismss were associated with an increase and decrease in risk, respectively. The functionalityy of either of these two polymorphisms, however, is uncertain, since our results mightt reflect the strong linkage disequilibrium across this gene cluster.
Paraoxonase,, an HDL-associated enzyme, may protect LDL-cholesterol against oxidation. Ourr results are in concordance with the findings of an earlier FH study, and homozygotes forr Ser311 Cys of paraoxonase-2 seem to be protected against CVD.24
Finally,, the Gly460Trp polymorphism of the a-adducin gene, associated with CVD in our cohort,, is a candidate gene for essential hypertension. In a prospective study of healthy individuals,, the 460Trp allele was associated with CVD, albeit only in a subgroup of hypertensivee patients."
Thee strengths of the present study lie in several areas. Firstly, the application of stringent criteriaa ensured a diagnosis of FH. In addition, the use of definitions of CVD and the independent adjudicationn committee led to appropriate definition of patients with and without CVD. Secondly,, by recruiting patients from all over the country, and by using our patient registration database,, we minimized selection on large families and genetically isolated communities. Moreover,, by choosing a cohort design and deriving our 'cases' and 'controls' from a common population,, we reduced the chance of population stratification and spurious associations. Thirdly,, the large size of the cohort provided sufficient power to detect small relative risks.
c;.-.,-,%% + u ^ ^{t^r+ ,^-t — „ ^ i , , „ „ , . „ u ; . - ™ % ;n -. ^ ; „ „ i „ „ „ „ „ „ ; „ u + u ~ ; ^ - f i , , ^ ~ ^ „ , J u . , ^ ~ !
.™,,-mU;,-~-s,-J KK n_c UICCHCI.L u i a p u i y i i i u i p i i o t i t 111 a .™,,-mU;,-~-s,-J i n y i c y c n c 11 n y i IL U C II I I IL»CI iv_cu uy (juiyiiiur|jiii:>iM:>
inn other genes, it was important to simultaneously assess the effects of multiple polymorphismss in many genes.
Fourthly,, our data collection process is unusual for retrospective studies. To obtain consistent datasets,, quality guidelines were implemented. A pilot study was performed to reconsider andd adjust all elements of the study design. Standardized history and physical examination wass documented in a tested case record form; handbooks with data collection guidelines weree used and interobserver studies were performed. Data collection was centrally monitored,, double data entry into the central database was applied, and a consistency checkk of the final data set was performed. In addition, by replicating 500 DNA samples, the accuracyy of genotyping could be confirmed.
Lastly,, we applied more stringent criteria for statistical significance to avoid problems of 'repetitivee testing', which often occurs in studies of multiple polymorphisms. Importantly, a cohortt study design enabled us to determine hazard ratios or relative risks. Many association studiess have had case-control designs with odds ratios as the outcome parameter. Whereas oddss ratios mimic relative risks remarkably well when the outcome of interest is rare, this is nott the case for CVD in FH (a prevalence of 33.1 % in our FH cohort), where odds ratios mightt exaggerate the actual risk.
Severall limitations of our study should also be mentioned. Firstly, in this retrospective study, thee primary source of data was the medical record. Medical records are primarily intended for patientt care and not for research purposes. Secondly, no standardized information was available onn life-style factors, such as dietary habits and physical activity. As a result, the interaction betweenn these environmental factors and genetic variants could not be ascertained. Finally,, our study included patients visiting a Lipid Clinic. In theory, patients with the most detrimentall genetic profiles might have died before referral. Therefore, genetic polymorphismss associated with more severe CVD or early death could have been missed, leadingg to an underestimation of the risk.
Inn conclusion, in the largest cohort of FH patients studied to date, we identified six polymorphismss in candidate genes related to CVD risk. Considering the limitations of
associationn studies, we suggest our results should be replicated, also in prospective studies off large and well-defined FH populations, in which genetic and environmental modifiers shouldd be carefully controlled. The long-term implications of our genetic studies, however, aree intriguing. Genotyping individuals for sets of polymorphisms could be helpful in improving cardiovascularr risk assessment of the individual FH patient. In addition, genetic markers mightt be used to institute individually tailored drug therapy. In this regard, the short-term clinicall implications of the present study might include clinical trials in which FH patients, stratifiedd according to genotype, are randomized to anti-platelet drugs {prothrombin gene
v u ii l ö i I L J ^( L i i i L i M j | j L i n , l i j i v c u i u y J ^ | J V J I y i F i u i f j i K J i i u i i i u i i y i u Lv. H j i i l ^ y *w Fi u n y VA u y v j u ^ n 1^ v^i
PPARa-agonists,, that act via modulation of apoC3 and apoA1 genes (ApoA1-C3-A4-A5 genee cluster).
Overall,, our results constitute a basis for further research and form a step forward in the unravelingg of the underlying mechanisms of CVD in FH.
Acknowledgments s
Thiss study was supported by a grant of the Netherlands Heart Foundation (98/165). J.J.P. Kasteleinn is an established investigator of the Netherlands Heart Foundation (grant 2000D039).. We are indebted to RMS personnel whoo supported this study. We acknowledge thee members of the independent adjudication committee: dr. R.J.G. Peters, cardiologist, prof.. dr. J. Stam, neurologist and prof. dr. D. Legemate, vascular surgeon. We thank all the patientss and the specialists of the participating Lipid Clinics.
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