Njajou, O.T.

HFE gene mutations increase the risk of coronary heart disease in women (Article)

2010-09-01T00:00:00Z

he purpose of the present study is to examine HFE gene mutations in relation to newly diagnosed (incident) coronary heart disease (CHD). In a population-based follow-up study of 7,983 individuals aged 55 years and older, we compared the risk of incident CHD between HFE carriers and non-carriers, overall and stratified by sex and smoking status. HFE mutations were significantly associated with an increased risk of incident CHD in women but not in men (hazard ratio [HR] for women = 1.7, 95% confidence interval [CI] 1.2-2.4 versus HR for men = 0.9, 95% CI 0.7-1.2). This increased CHD risk associated with HFE mutations in women was statistically significant in never smokers (HR = 1.8, 95% CI 1.1-2.8) and current smokers (HR = 3.1, 95% CI 1.4-7.1), but not in former smokers (HR = 1.3, 95% CI 0.7-2.4). HFE mutations are associated with increased risk of incident CHD in women.

HFE variants, APOE and Alzheimer's disease: Findings from the population-based Rotterdam Study (Article)

2009-02-01T00:00:00Z

Iron is a reactive oxygen species and has been implicated in the pathogenesis of Alzheimer's disease (AD). In a population-based cohort study, including 268 incident AD patients and 2079 control individuals, we investigated the influence of the HFE C282Y and H63D variants and the apolipoprotein E4 (APOEε4) allele on the incidence, and age at onset of AD. There was no significant difference in the frequency of HFE variants in AD patients compared to controls. There was no significant effect modification by the APOEε4 allele. The mean age at onset was earlier in H63D homozygotes compared to non-carriers of this variant, in men (76.9 ± 3.2 compared to 82.2 ± 1.7) and women (82.1 ± 3.9 compared to 84.5 ± 1.7). In addition, in APOEε4 carriers, the mean age at onset of AD was earlier in men homozygous for the H63D variant (73.2 ± 2.1 versus 78.7 ± 1.6, p = 0.05). Our results suggest that HFE variants are not strong determinants of AD in the general population but may modify the age of onset.

The H63D variant in the HFE gene predisposes to arthralgia, chondrocalcinosis and osteoarthritis (Article)

2007-11-01T00:00:00Z

Objectives: To investigate the relation between the HFE C282Y and H63D variants with arthralgia and joint pathology in the population-based Rotterdam Study. Methods: From a cohort of 7983 people aged 55 years and over, 2095 randomly drawn subjects were genotyped for C282Y and H63D variants. We compared the frequency of arthralgia, and the presence of chondrocalcinosis, osteophytes, joint space narrowing and radiographic osteoarthritis in hand, hip and knee joints, and Heberden's nodes in carriers of HFE variants with that in non-carriers. Results: Overall, there was a significantly higher frequency of arthralgia (odds ratio 1.6; 95% CI 1.0 to 2.6), oligoarthralgia (2.3; 1.2 to 4.4) and Heberden's nodes (2.0; 1.1 to 3.8) in H63D homozygotes compared with non-carriers. In subjects aged 65 years or younger, H63D homozygotes had significantly more often polyarthralgia (3.1; 1.3 to 7.4), chondrocalcinosis in hip or knee joints (4.7; 1.2 to 18.5), and more hand joints with osteophytes (6.1±1.0 vs 4.4±0.3), space narrowing (2.8±0.5 vs 1.0±0.1), radiographic osteoarthritis (4.4±0.7 vs 2.0±0.2) and Heberden's nodes (3.1; 1.3 to 12.8) than non-carriers. We found no relation of arthralgia or joint pathology to C282Y, but compound heterozygotes had a significantly higher frequency of arthralgia (2.9; 1.0 to 9.3), chondrocalcinosis in hip joints (6.5; 1.8 to 22.3), and an increased number of osteophytes in knee (6.9±1.2, n = 5 vs 2.4±0.1) joints at a later age (>65 years). Conclusions: The HFE H63D variant may explain, at least in part, the prevalence of arthralgia in multiple joints sites, chondrocalcinosis, and hand osteoarthritis in the general population.

Familial clustering of multiple sclerosis in a Dutch genetic isolate (Article)

2007-01-01T00:00:00Z

Multiple sclerosis (MS) is a complex disease with a substantial, yet poorly identified, genetic influence. We estimated the pattern of familial aggregation of MS in a recent genetically isolated population in the Netherlands. Forty-eight MS patients were identified. Their relationship was evaluated by tracing extended pedigrees, making use of municipal and church records. Of the 48 MS patients, 24 could be linked to a common ancestor in 14 generations. However, multiple relationships exist between patients and, to take these into account, we calculated inbreeding and kinship coefficients. We found that MS patients from the isolate were significantly more often related to each other and significantly more often inbred than a non-MS control group, drawn from the same isolate. There was no clustering of Type I diabetes and autoimmune thyroid diseases in families of MS patients from this isolate. Finally, HLA typing was performed. Although there was a trend towards a higher prevalence of the HLA DRB1*15 allele in patients compared to controls, differences did not reach significance. This study suggests familial aggregation in the genetically isolated population. The high level of inbreeding makes this population valuable for finding novel genes involved in MS.

Angiotensin-converting enzyme gene insertion/deletion polymorphism and breast cancer risk. (Article)

2005-09-01T00:00:00Z

BACKGROUND: The renin-angiotensin system plays an important role in homeostasis and lately, its main effector, angiotensin II, has been attributed with angiogenic and growth factor actions in the breast tissue. Previous studies have shown that the insertion/deletion (I/D) polymorphism in the angiotensin-converting enzyme (ACE) gene accounts for the variability of ACE plasma concentrations. The use of ACE inhibitors and the ACE I/D polymorphism may be linked to breast cancer risk. In this study, we evaluate the relationship of the ACE I/D polymorphism with breast cancer risk in Caucasian postmenopausal women. METHODS: The ACE I/D polymorphism was genotyped in 4,117 women participants in the Rotterdam Study. Baseline information was obtained through a questionnaire. We conducted a logistic regression and survival analysis to assess the risk of breast cancer by the ACE genotype. RESULTS: The DD carriers showed a significantly increased risk of developing breast cancer when compared with the II carriers (odds ratio, 1.86; 95% confidence interval, 1.06-3.27; P = 0.03). This association remained after adjusting for other risk factors, including body mass index, age at menarche, age at menopause, hormone replacement therapy, and hypertension. Our survival analysis showed that the cancer-free survival was significantly reduced in DD compared with II carriers (hazard ratio, 1.80; 95% confidence interval, 1.07-3.01; P = 0.03). CONCLUSIONS: Our results suggest that the ACE I/D polymorphism plays an important role in breast cancer risk and disease-free survival in Caucasian postmenopausal women.

The -514 C->T hepatic lipase promoter region polymorphism and plasma lipids: a meta-analysis. (Article)

2004-08-01T00:00:00Z

Investigations of the -514 C-->T single nucleotide polymorphism (SNP) in the hepatic lipase (HL) gene promoter region (LIPC) have yielded contradictory results regarding its association with changes in plasma lipids. The current study is a meta-analysis of 25 publications on this SNP, comprising over 24,000 individuals, and its relationship with total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol (HDL), triglycerides, and HL activity. Significant decreases were observed in HL activity for both the CT and TT genotypes compared with the CC genotype [weighted mean difference (WMD), -5.83 mmol/liter.h (95% confidence interval, -8.48, -3.17) and -11.05 mmol/liter.h (95% confidence interval, -14.74, -7.36), respectively]. Moreover, significant increases in HDL were found; the CT to CC comparison showed an increase in WMD of 0.04 mmol/liter (95% confidence interval, 0.02, 0.05) mmol/liter, and the increase in the TT vs. CC difference was WMD of 0.09 mmol/liter (95% confidence interval, 0.07, 0.12). These changes appear to be stepwise, implying an allele dosage effect. All P values for these associations were less than 0.001. This meta-analysis demonstrates the importance of the -514C-->T SNP in determining HL activity and plasma HDL concentration and helps quantify the role that hepatic lipase plays in the metabolism of HDL.

Does Bilirubin protect against hemochromatosis gene (HFE) related mortality? (Article)

2004-01-01T00:00:00Z

Serum bilirubin is an important antioxidant that is found at increased levels in hereditary hemochromatosis patients. We hypothesized that increased levels of serum bilirubin may play a protective role against oxidative stress induced by iron overload in carriers of mutations in the hereditary hemochromatosis gene (HFE). We studied the relation between serum total bilirubin, serum iron levels, the HFE C282Y and H63D mutations, and mortality. The study was conducted in 2,332 randomly selected subjects from the Rotterdam Study, a population-based follow-up study of people aged 55 years or over. Serum bilirubin levels were significantly correlated with serum iron (Pearson's correlation coefficient (r) = 0.4, P < 0.001), transferrin saturation (r = 0.4, P < 0.001), and serum ferritin (r = 0.2, P < 0.05). Carriers of the HFE mutations had higher levels of bilirubin compared to wild-type homozygotes. The relation was the strongest in H63D heterozygotes or homozygotes and C282Y heterozygotes. High levels of serum bilirubin were associated with a 2.8 (95% CI 0.9-8.8) fold reduction in mortality in H63D homozygotes and a 2.2 (1.0-4.7) fold reduction in mortality in C282Y heterozygotes. Taken together, our data suggest that the high levels of the antioxidant bilirubin may counteract the adverse effect of oxidative stress induced by iron overload. This may explain in part the reduced penetrance of the HFE mutations.

A population-based study of the effect of the HFE C282Y and H63D mutations on iron metabolism (Article)

2003-03-01T00:00:00Z

The C282Y and H63D mutations in the HFE gene are important causes of hemochromatosis. In the elderly, these mutations might be associated with increased morbidity because of the lifelong accumulation of iron. In a population-based sample of the elderly, we determined the value of genotyping for HFE mutations to screen for subclinical hemochromatosis. HFE genotype frequencies were determined in a random group of 2095 subjects (55 years and over). In this random group, we selected within the six genotype groups a total of 342 individuals and measured their serum transferrin saturation, iron and ferritin levels. We also estimated the heritability and parameters needed to evaluate screening, including the sensitivity, specificity, positive and negative predictive values (PPV, NPV) of HFE genotypes. Iron parameters were significantly increased in subjects homozygous, heterozygous or compound heterozygous. The effect of the mutations was more pronounced in men than in women. For the H63D mutation, an allele dose effect was observed. The HFE gene explained about 5% of the variability in serum iron indices. The PPV for hemochromatosis for the C282Y homozygous was 100% in men and 67% in women. The NPV of the wild-type allele was 97% for both men and women. The sensitivity of both mutations was 70% for men and 52% for women and the specificity was 62% for men and 64% for women. Our study shows that the HFE C282Y and H63D are determinants of iron parameters in the elderly and will be effective in detecting individuals at high risk of hemochromatosis. However, when screening based on these two mutations, some individuals with subclinical hemochromatosis will be missed.

Mutations in the hemochromatosis gene (HFE) and stroke (Article)

2002-10-01T00:00:00Z

BACKGROUND AND PURPOSE: Increased serum iron is found to be a risk factor for stroke. Carriers of HFE C282Y and H63D mutations have elevated serum iron levels and may have an increased risk for stroke. We studied the association between HFE gene mutations, carotid atherosclerosis, and stroke. METHODS: We compared the frequency of the HFE C282Y and H63D gene mutations in 202 prevalent and incident cases of stroke with that of 2730 controls from a population-based study, the Rotterdam Study. The influence of HFE mutations on the relationship between hypertension, smoking, and stroke was studied by use of a logistic regression model. In the analyses of hypertension, we used noncarriers and nonhypertensives as reference; in the analysis of smoking, we used noncarriers and those who never smoked as the reference group. Furthermore, we studied the mean intima-media thickness of the common carotid artery in relation to hypertension, smoking, and the HFE genotype in subjects without stroke. RESULTS: The percentage of both C282Y and H63D carriers in cases (43.7%, n=87) did not differ significantly (P=0.09) from that of controls (37.6%, n=986). The odds ratio for stroke for HFE carriers who also suffered from hypertension was 3.0 (95% CI, 1.9 to 4.6), and for HFE carriers who were also smokers, the odds ratio for stroke was 2.6 (95% CI, 1.4 to 5.0). The mean+/-SD intima-media thickness of the carotid artery was 0.77+/-0.14 mm for noncarriers without a history of hypertension or smoking compared with 0.81+/-0.17 mm for HFE carriers who smoked (P<0.004) and 0.84+/-0.20 mm for HFE carriers who were hypertensive (P<0.001). CONCLUSIONS: Mutations in the HFE gene were not significantly related to stroke or atherosclerosis in the carotid artery. The HFE gene may modify the relationship between smoking and stroke.

A genetic epidemiologic study of hemochromatosis (Doctoral Thesis)

2002-06-26T00:00:00Z

The goal of genetic epidemiology is to study the genetic etiology of diseases. There were t\vo main aims for the present thesis. The first aim was to study the effects of the hemochromatosis gene (HFE) mutations on serum iron levels and disease associated conditions. Secondly, we aimed at identifYing other genes involved in hemochromatosis. Numerous studies have been carried out on the genetics and epidemiology of hemochromatosis. Still there is a lot of controversies in the literature as to what the contributions of HFE gene mutations are to liver diseases, diabetes mellitus, and vascular pathology. Most controversies are due to differences in study designs, casedefinition of hemochromatosis, ethnic composition of populations studied, risk modifiers, and genetic heterogeneity. In order to translate the results of genetic research into public health policies, population-based studies are necessary to evaluate the impact of the gene on risk of disease, mortality and quality of life. In this thesis, we have used a population-based cohort study of elderly individuals, the Rotterdam Study, to quantifY the effect of HFE mutations on several disorders. Further, a genomic screen was carried out in a family with an autosomal dominant form of hereditary hemochromatosis from a genetically isolated community in the south-west of The Netherlands. This chapter focuses on the main findings of this thesis and their relevance. Chapter 5.2 discusses the findings of population-based studies of HFE and the genome screen. Some methodological issues as well as suggestions for future research are embedded. In chapter 5.3, future perspectives and final remarks are given.

The role of hemochromatosis C282Y and H63D gene mutations in type 2diabetes: findings from the Rotterdam Study and meta-analysis (Letter To Editor)

2002-01-01T00:00:00Z

Letter

A mutation in SLC11A3 gene is associated with autosomal dominant hemochromatosis (Article)

2001-07-20T00:00:00Z

Hereditary hemochromatosis (HH) is a very common disorder characterized by iron overload and multi-organ damage. Several genes involved in iron metabolism have been implicated in the pathology of HH (refs. 1-4). We report that a mutation in the gene encoding Solute Carrier family 11, member A3 (SLC11A3), also known as ferroportin, is associated with autosomal dominant hemochromatosis.