Morbidity, risk of cancer and mortality in 3645 HFE mutations carriers.

BACKGROUND & AIMS: Mutations in the HFE gene can lead to hereditary haemochromatosis (HH) and have been suggested to increase the risk of extra-hepatic diseases, especially breast and colorectal cancer. Here we investigated long-term outcomes of Swedish patients with HFE mutations. METHODS: We identified 3645 patients with a homozygous p.C282Y (62%) or a compound heterozygous p.C282Y/p.H63D (38%) mutation from eight centres in Sweden between 1997 and 2017. These were matched 1:10 by age, sex and county of residence to reference individuals from the general population. We ascertained incident outcomes until the end of 2017 by linkage to national registers. Studied outcomes were HH, cirrhosis, hepatocellular carcinoma (HCC), breast cancer (in women), colorectal cancer, type 1 and 2 diabetes, hypothyroidism, Parkinson's disease and mortality. Cox proportional hazards regression was used to estimate hazard ratios for these outcomes. RESULTS: Median age at diagnosis was 52 years, 44% were females. During a mean follow-up of 7.9 years, we found an increased risk for HCC, HH, cirrhosis, type 2 diabetes, osteoarthritis and death. Excess mortality was only seen in men. No increased risk was seen for colorectal or breast cancer. Liver-related outcomes were rare, with a cumulative incidence of <1%. CONCLUSIONS: Individuals found to be HFE mutation carriers in a university hospital setting had an increased risk for mortality in men, along with increased risks of cirrhosis, HCC, diabetes type 2, and osteoarthritis. In general, the absolute risk for adverse outcomes was low and no increased risk for colon or breast cancer was observed.

The p.H63D allele of the HFE gene protects against low iron stores in Sri Lanka.

In hereditary hemochromatosis, iron overload is associated with homozygosity for the p.C282Y mutation. A second mutation, p.H63D, occurs at significant frequencies in Europe, North Africa, the Middle East and Asia. Early studies in Sri Lanka indicated that the variant had arisen independently, suggesting that it had been the subject of selective pressure. However, its role in iron absorption is unclear. In a survey of 7526 Sri Lankan secondary school students, we determined hemoglobin genotype and measured red cell indices, serum ferritin, transferrin receptor, iron zinc protoporphyrin and hepcidin. These variables were compared according to the presence or absence of the p.H63D variant in a subset of 1313 students for whom DNA samples were available. Students were classified as having low red cell indices if they had an MCV <80 fl and/or MCH <27 pg. Hetero and/or homozygosity for the p.H63D variant was more common in students with normal than low red cell indices (16.4% and 11.9% respectively; p = 0.019). Iron biomarkers and red cell indices were greater in children with the p.H63D variant than in normal and this was statistically significant for MCV (p = 0.046). Our findings suggest that selective pressure by mild iron deficiency contributes to the high frequencies of the p.H63D variant.

The role of HFE genotype in macrophage phenotype.

BACKGROUND: Iron regulation is essential for cellular energy production. Loss of cellular iron homeostasis has critical implications for both normal function and disease progression. The H63D variant of the HFE gene is the most common gene variant in Caucasians. The resulting mutant protein alters cellular iron homeostasis and is associated with a number of neurological diseases and cancer. In the brain, microglial and infiltrating macrophages are critical to maintaining iron homeostasis and modulating inflammation associated with the pathogenic process in multiple diseases. This study addresses whether HFE genotype affects macrophage function and the implications of these findings for disease processes. METHODS: Bone marrow macrophages were isolated from wildtype and H67D HFE knock-in mice. The H67D gene variant in mice is the human equivalent of the H63D variant. Upon differentiation, the macrophages were used to analyze iron regulatory proteins, cellular iron release, migration, phagocytosis, and cytokine expression. RESULTS: The results of this study demonstrate that the H67D HFE genotype significantly impacts a number of critical macrophage functions. Specifically, fundamental activities such as proliferation in response to iron exposure, L-ferritin expression in response to iron loading, secretion of BMP6 and cytokines, and migration and phagocytic activity were all found to be impacted by genotype. Furthermore, we demonstrated that exposure to apo-Tf (iron-poor transferrin) can increase the release of iron from macrophages. In normal conditions, 70% of circulating transferrin is unsaturated. Therefore, the ability of apo-Tf to induce iron release could be a major regulatory mechanism for iron release from macrophages. CONCLUSIONS: These studies demonstrate that the HFE genotype impacts fundamental components of macrophage phenotype that could alter their role in degenerative and reparative processes in neurodegenerative disorders.

The risk of new-onset cancer associated with HFE C282Y and H63D mutations: evidence from 87,028 participants.

To investigate the association between mutation of HFE (the principal pathogenic gene in hereditary haemochromatosis) and risk of cancer, we conducted a meta-analysis of all available case-control or cohort studies relating to two missense mutations, C282Y and H63D mutations. Eligible studies were identified by searching databases including PubMed, Embase and the ISI Web of Knowledge. Overall and subgroup analyses were performed and odds ratios (ORs) combined with 95% confidence intervals (CIs) were applied to evaluate the association between C282Y mutation, H63D mutation and cancer risk. Sensitivity and cumulative analyses were used to evaluate the stability of the results. A total of 36 eligible studies were included, comprising 13,680 cases and 73,348 controls. C282Y was significantly associated with elevated cancer risk in a recessive genetic model (OR: 1.991, 95% CI: 1.448-2.737). On subgroup analysis stratified by cancer type, statistically significantly increased cancer risks were found for breast cancer, colorectal cancer and hepatocellular carcinoma in a recessive model. When stratified by territory, a significantly increased risk of cancer was found in Oceanic populations in a recessive model and in Asian populations in an allele model and dominant model. H63D mutation did not significantly increase overall cancer risk in any genetic model. However, when, stratified by territory, an increased cancer risk was found in the Asian population in an allele and dominant. C282Y but not H63D mutation was related to elevated cancer risk. Further large-scale studies considering gene-environment interactions and functional research should be conducted to further investigate this association.

Statins accelerate disease progression and shorten survival in SOD1(G93A) mice.

INTRODUCTION: HMG-CoA reductase inhibitors (statins) and H63D HFE polymorphism may modify amyotrophic lateral sclerosis (ALS). We hypothesized that statins worsen phenotype in ALS mice, dependent on HFE genotype. METHODS: Mice harboring SOD1(G93A) heterozygous for H67D Hfe (homologous to human H63D HFE) were administered simvastatin and/or coenzyme Q10, and were allowed to reach end stage. Disease progression was measured by grip strength. A separate group of animals was administered simvastatin and euthanized at the symptomatic 120-day time-point. Mitochondria from gastrocnemius muscle and lumbar spine were analyzed. RESULTS: Simvastatin and H67D Hfe accelerated disease progression. Simvastatin decreased survival. Coenzyme Q10 did not rescue statin-induced effects. Statins did not alter mitochondrial protein levels. CONCLUSIONS: Statins and Hfe genotype alter disease course in the ALS mouse model. Because the H63D HFE polymorphism is present in 30% of patients with ALS, studying disease progression in patients who receive statins, stratified for HFE genotype, may guide therapy. Muscle Nerve, 2016 Muscle Nerve 54: 284-291, 2016.

Association of HFE gene C282Y and H63D mutations with liver cirrhosis in the Lithuanian population.

BACKGROUND AND OBJECTIVE: Liver cirrhosis is the end-stage disease of chronic liver injury. Due to differences in the natural course of chronic liver diseases, identification of genetic factors that influence individual outcomes is warranted. HFE-linked hereditary hemochromatosis (HH) predisposes disease progression to cirrhosis; however, the role of heterozygous C282Y or H63D mutations in the development of cirrhosis in the presence of other etiological factors is still debated. The aim of this study was to determine the association between heterozygous C282Y and H63D mutations and non-HH liver cirrhosis in Lithuanian population. MATERIALS AND METHODS: The patient cohort consisted of 209 individuals. Diagnosis of cirrhosis was confirmed by clinical, laboratory parameters, liver biopsy, and radiological imaging. Control samples were obtained from 1005 randomly selected unrelated healthy individuals. HFE gene mutations were determined using the PCR-RFLP method. RESULTS: The most common causes of cirrhosis were hepatitis C (33.9%), hepatitis B (13.6%), and alcohol (25.8%). C282Y allele was associated with the presence of cirrhosis (OR=2.07; P=0.005); this was also observed under recessive model for C282Y (OR=2.06, P=0.008). The prevalence of C282Y allele was higher in cirrhotic men than in controls (7.0% vs. 2.8%, P=0.002). The carriage of H63D risk allele (OR=1.54; P=0.02), heterozygous C282Y/wt and homozygous H63D/H63D genotypes were associated with liver cirrhosis in males (OR=2.48, P=0.008, and OR=4.13, P=0.005, respectively). CONCLUSIONS: Heterozygous C282Y mutation of the HFE gene was associated with liver cirrhosis in the Lithuanian population. In gender-related analysis, heterozygous C282Y and homozygous H63D mutations were linked to liver cirrhosis in men, not in women.

[The comparison of three molecular genetic techniques for identifying major mutations in gene HFE related to development of inherent hemochromatosis.]

The three main mutations in gene HFE (C282Y, H63D, S65C) are the cause of development of 97% of cases of inherent hemochromatosis. It is known that about 85% of patients with inherent hemochromatosis are either homo-zygotic agents of mutation C282Y or carry compound-heterozygote C282Y/H63D. Therefore, the molecular genetic study intended for detection of these three mutations in gene HFE takes important place in diagnostic of inherent hemochromatosis. The study was organized to develop methods for detection of mutations C282Y, H63D, S65C on the basis of two molecular genetic methods - polymerase chain reaction in real-time and pyrosequenation. As reference method was used published method by Moyses C.B. et al. (2008). These methods were applied to analyzing 129 DNA samples. There were no discordant results. Among analyzed clinical DNA samples, mutant alleles of gene HFE were detected in 42 samples (32.5%)ю The mutation C282Y is detected in heterozygotic condition in 4 samples (3.1%); mutation H63D was detected in heterozygotic condition in 31 samples (24%) and in homo-zygotic condition in 4 samples (4%). The mutation S65C encountered in heterozygotic condition in one sample (0.8%) and in one sample compound-heterozygote H63D/S65C was detected (0.8%). The comparative characteristic of these three methods was made according the following parameters: time, number of analysis stages and convenience of interpretation of results. The main merit of method based on polymerase chain reaction in real-time is time of analysis implementation. The main merit of method based on pyrosequenation is automatic identification of genotype.

H63D HFE genotype accelerates disease progression in animal models of amyotrophic lateral sclerosis.

H63D HFE is associated with iron dyshomeostasis and oxidative stress; each of which plays an important role in amyotrophic lateral sclerosis (ALS) pathogenesis. To examine the role of H63D HFE in ALS, we generated a double transgenic mouse line (SOD1/H67D) carrying the H67D HFE (homologue of human H63D) and SOD1(G93A) mutations. We found double transgenic mice have shorter survival and accelerated disease progression. We examined parameters in the lumbar spinal cord of double transgenic mice at 90days (presymptomatic), 110days (symptomatic) and end-stage. Transferrin receptor and L-ferritin expression, both indicators of iron status, were altered in double transgenic and SOD1 mice starting at 90days, indicating loss of iron homeostasis in these mice. However, double transgenic mice had higher L-ferritin expression than SOD1 mice. Double transgenic mice exhibited increased Iba-1 immunoreactivity and caspase-3 levels, indicating increased microglial activation which would be consistent with the higher L-ferritin levels. Although both SOD1 and double transgenic mice had increased GFAP expression, the magnitude of the increase was higher in double transgenic mice at 110days, suggesting increased gliosis in these mice. Increased hemeoxygenase-1 and decreased nuclear factor E2-related factor 2 levels in double transgenic mice strongly suggest the accelerated disease process could be associated with increased oxidative stress. There was no evidence of TAR-DNA-binding protein 43 mislocalization to the cytoplasm in double transgenic mice; however, there was evidence suggesting neurofilament disruption, which has been reported in ALS. Our findings indicate H63D HFE modifies ALS pathophysiology via pathways involving oxidative stress, gliosis and disruption of cellular functions.

Ancestral association between HLA and HFE H63D and C282Y gene mutations from northwest Colombia.

A significant association between HFE gene mutations and the HLA-A*03-B*07 and HLA-A*29-B*44 haplotypes has been reported in the Spanish population. It has been proposed that these mutations are probably connected with Celtic and North African ancestry, respectively. We aimed to find the possible ancestral association between HLA alleles and haplotypes associated with the HFE gene (C282Y and H63D) mutations in 214 subjects from Antioquia, Colombia. These were 18 individuals with presumed hereditary hemochromatosis ("HH") and 196 controls. The HLA-B*07 allele was in linkage disequilibrium (LD) with C282Y, while HLA-A*23, A*29, HLA-B*44, and B*49 were in LD with H63D. Altogether, our results show that, although the H63D mutation is more common in the Antioquia population, it is not associated with any particular HLA haplotype, whereas the C282Y mutation is associated with HLA-A*03-B*07, this supporting a northern Spaniard ancestry.

Analysis of HFE genes C282Y, H63D, and S65D in patients with hyperferritinemia from northeastern Brazil.

BACKGROUND: Hereditary hemochromatosis (HH) is a genetic disease caused by the high absorption and deposition of iron in several organs. This accumulation results in several clinical complications such as cirrhosis, arthritis, cardiopathies, diabetes, sexual disorders, and skin darkening. The H63D and C282Y mutations are well defined in the HH etiology. The objective of this article is identification of the H63D and C282Y mutations in the HFE protein gene and the frequency assessment of these mutations in patients with persistent increase of serum ferritin in patients from Natal City from state of Rio Grande do Norte, located in northeastern Brazil. RESULTS: Of the 299 patients studied for C282Y and H63D, 48.49% showed absence of mutation and 51.51% showed some sort of mutation: heterozygous C282Y mutation in 4.35% patients, homozygous C282Y mutation in 2.67% patients, heterozygous H63D mutation in 31.44% patients, homozygous H63D mutation in 8.03% patients, and heterozygous for the mutation in both genes (C282Y/H63D) in 5.02% patients. The S65C mutation was studied in 112 patients and heterozygous mutation (S65D/WT) in 2.67% of patients and double mutation (H63D/S65C) in 1.78% of patients were observed. CONCLUSION: Due to the high prevalence of hemochromatosis, its genetic diagnosis has become a challenge, especially in the high-risk group.

Hereditary hemochromatosis caused by a C282Y/H63D mutation in the HFE gene: A case report.

Hereditary hemochromatosis (HH) is a disease characterized by disordered iron metabolism. It often involves mutations of the HFE gene, which encodes the homeostatic iron regulator protein (HFE), as well as mutations affecting hepcidin antimicrobial peptide, hemojuvelin, or transferrin receptor 2. Historically, HH has been observed primarily in European and European diaspora populations, while classical HH is rare in Asian populations, including in China. In this article, we report a rare case of HH in a Chinese man that could be attributed to a heterozygous C282Y/H63D HFE mutation. Based on clinical examination, liver biopsy, and genetic testing results, the patient was diagnosed with HH. Clinical signs and symptoms and serum iron-related test results were recorded for a period of two years after the patient began treatment. Over this observation period, the patient was subjected to 25 phlebotomies (accounting for a total blood loss of 10.2 L). His serum ferritin levels decreased from 1550 µg/L to 454 µg/L, his serum iron concentration decreased from 40 µmol/L to 24.6 µmol/L, and his transferrin saturation decreased from 97.5% to 55.1%. Early diagnosis is essential for patients with HH to obtain good outcomes. Regular phlebotomy after diagnosis can improve HH symptoms and delay HH disease progression.

A Rare Case of Heterozygous C282Y Mutation Causing Hereditary Hemochromatosis With Acute Pancreatitis.

Hereditary hemochromatosis (HH) is the most common autosomal recessive genetic disorder globally for Caucasians. HH is known as an iron metabolism disorder where there is an increase in iron absorption in the body. HH is not localized but a systemic disease; the manifestations of HH include cirrhosis, diabetes mellitus, cardiomyopathy, and pancreatitis. This case is about a 53-year-old female with a past medical history of heterozygous hereditary hemochromatosis who presents to the emergency department with abdominal pain, nausea, and vomiting and was found to have acute pancreatitis. This case report helps signify the importance of identifying and treating symptomatic heterozygous carriers of the HH gene mutation.

Clinical characteristics of HFE C282Y/H63D compound heterozygotes identified in a specialty practice: key differences from HFE C282Y homozygotes.

BACKGROUND: Patients with p.C282Y homozygous (p.C282Y) HFE mutations are more likely to develop hemochromatosis (HC) than p.C282Y/p.H63D compound heterozygotes (p.C282Y/H63D). RESEARCH DESIGN AND METHODS: We conducted a retrospective chart review of 90 p.C282Y and 31 p.C282Y/H63D patients at a referral practice to illustrate the differences in the natural history of the disease in these two HC cohorts. RESULTS: Over a median follow-up of 17 years, p.C282Y had higher mean serum ferritin (1105 mg/dL vs. 534 mg/dL, p = 0.001) and transferrin saturations (75.3% vs. 49.5%, p = 0.001) at diagnosis. p.C282Y underwent more therapeutic phlebotomies (TP) till de-ironing (mean 24 vs. 10), had higher mean mobilized iron stores (4759 mg vs. 1932 mg), and required more annual maintenance TP (1.9/year vs. 1.1/year, p = 0.039). p.C282Y/H63D were more likely to have obesity (45.2% vs. 20.2%, p = 0.007) at diagnosis, with a non-significant trend toward consuming more alcohol. There was no significant difference in the development of HC-related complications between the two cohorts. CONCLUSIONS: p.C282Y have a higher mobilizable iron and require more TP. p.C282Y/H63D likely require additional insults such as obesity or alcohol use to develop elevated ferritin. De-ironing may mitigate the risk of developing HC-related complications.

H63D HFE polymorphisms are associated with increased disease duration and decreased muscle superoxide dismutase-1 expression in amyotrophic lateral sclerosis patients.

INTRODUCTION: H63D HFE polymorphisms increase the risk of neurodegenerative disorders and, specifically, may increase amyotrophic lateral sclerosis (ALS) risk. Investigating the physiological alterations induced by H63D polymorphisms in ALS patients may elucidate mechanisms by which this genotype alters disease. METHODS: Clinical measures and muscle biopsies were available from patients previously diagnosed with ALS who underwent HFE genotyping. Clinical outcomes and SOD1 protein expression were analyzed using standard statistical analyses. RESULTS: ALS patients harboring H63D HFE (n = 16) had 28.1 months longer average disease duration and 39.3% lower muscle SOD1 protein than ALS patients with wild-type HFE (n = 22). CONCLUSIONS: Combined with previous reports suggesting the H63D polymorphism is associated with ALS, these results support a model wherein the H63D polymorphism is involved in ALS by means of pathways involving SOD1 but may limit cellular damage in individuals who develop disease. The association between HFE genotype and disease duration has important implications for clinical care and treatment trials.

HFE hemochromatosis in African Americans: Prevalence estimates of iron overload and iron overload-related disease.

BACKGROUND: Little is known about the prevalence of HFE (homeostatic iron regulator) hemochromatosis in African Americans (AA). METHODS: We defined AA as self-identified AA, blacks, or non-Hispanic blacks. We defined hemochromatosis-associated HFE genotypes as p.C282Y/p.C282Y and p.C282Y/p.H63D. We compiled prevalences of these genotypes in AA using published population and cohort data and numbers of men and women ≥18 y‬ in 2018 U.S. Census estimates. We defined iron overload (IO) and IO-related disease by genotype as previously reported in population and cohort studies of hemochromatosis in whites of European ancestry. We used these definitions to estimate prevalences and numbers of AA with IO and IO-related disease associated with hemochromatosis-associated HFE genotypes. RESULTS: There were ∼16,287,599 men and ∼17,644,898 women. HFE genotypes and their respective prevalences were: p.C282Y/p.C282Y, 0.00017 (6/34,905) [95% confidence interval 0.000034, 0.00031] and p.C282Y/p.H63D, 0.0012 (41/33,596) [0.000084, 0.0016]. IO prevalences were: men 0.000076 [0.000072, 0.000081] and women 0.0000061 [0.0000050, 0.0000073]. IO-related disease prevalences were: men 0.000063 [0.000059, 0.000067] and women 0.0000021 [0.0000014, 0.0000027]. There were ∼1021 [961, 1091] men and ∼36 [25, 48] women with IO-related disease. CONCLUSIONS: We conclude that ∼1/25,061 AA >18 y have a hemochromatosis-associated HFE genotype and IO and that ∼1/32,103 AA >18 y have a hemochromatosis-associated HFE genotype and IO-related disease.

A Rare Case of Hereditary Hemochromatosis Presenting With Porphyria Cutanea Tarda.

Hereditary hemochromatosis is an autosomal recessive condition with incomplete penetrance that is most commonly caused by a mutation in the HFE gene. Hereditary hemochromatosis can remain asymptomatic in some patients until triggered by certain events. Porphyria cutanea tarda is a condition that can lead to iron overload due to defective synthesis of heme and can cause the onset of adult-onset hereditary hemochromatosis. Herein, we present a case where a 77-year-old man presented with painful blisters on the sun-exposed areas of his hands and was diagnosed with porphyria cutanea tarda. Further testing for mutations in the HFE gene given elevated ferritin was performed and returned positive, which confirmed the diagnosis of adult-onset hereditary hemochromatosis. The patient received serial therapeutic phlebotomy for iron overload and adopted lifestyle modifications such as avoiding sun exposure of upper extremities. The patient's blisters and laboratory iron panel parameters improved with continued phlebotomy. Therapeutic phlebotomy has been demonstrated to be an effective first-line therapy in patients with dual diagnosis. Our case highlights that cutaneous symptoms due to porphyria cutanea tarda may be the first presenting symptom in patients with underlying hemochromatosis.

Association between Polymorphisms of Hemochromatosis (HFE), Blood Lead (Pb) Levels, and DNA Oxidative Damage in Battery Workers.

Occupational exposure to lead (Pb) continues to be a serious public health concern and may pose an elevated risk of genetic oxidative damage. In Brazil, car battery manufacturing and recycling factories represent a great source of Pb contamination, and there are no guidelines on how to properly protect workers from exposure or to dispose the process wastes. Previous studies have shown that Pb body burden is associated with genetic polymorphisms, which consequently may influence the toxicity of the metal. The aim of this study was to assess the impact of Pb exposure on DNA oxidative damage, as well as the modulation of hemochromatosis (HFE) polymorphisms on Pb body burden, and the toxicity of Pb, through the analysis of 8-hydroxy-2'-deoxyguanosine (8-OHdG), in subjects occupationally exposed to the metal. Male Pb-exposed workers (n = 236) from car battery manufacturing and recycling factories in Brazil participated in the study. Blood and plasma lead levels (BLL and PLL, respectively) were determined by ICP-MS and urinary 8-OHdG levels were measured by LC-MS/MS, and genotyping of HFE SNPs (rs1799945, C → G; and 1800562, G → A) was performed by TaqMan assays. Our data showed that carriers of at least one variant allele for HFE rs1799945 (CG + GG) tended to have higher PLL than those with the non-variant genotype (ß = 0.34; p = 0.043); further, PLL was significantly correlated with the levels of urinary 8-OHdG (ß = 0.19; p = 0.0060), while workers that carry the variant genotype for HFE rs1800562 (A-allele) showed a prominent increase in 8-OHdG, as a function of PLL (ß = 0.78; p = 0.046). Taken together, our data suggest that HFE polymorphisms may modulate the Pb body burden and, consequently, the oxidative DNA damage induced by the metal.

The HFE p.H63D (p.His63Asp) Polymorphism Is a Modifier of ALS Outcome in Italian and French Patients with SOD1 Mutations.

Background: Data from published studies about the effect of HFE polymorphisms on ALS risk, phenotype, and survival are still inconclusive. We aimed at evaluating whether the p.H63D polymorphism is a modifier of phenotype and survival in SOD1-mutated patients. Methods: We included 183 SOD1-mutated ALS patients. Mutations were classified as severe or mild according to the median survival of the study population. Patients were screened for the HFE p.H63D polymorphism. Survival was calculated using the Kaplan-Meier modeling, and differences were measured by the log-rank test. Multivariable analysis was performed with the Cox proportional hazards model (stepwise backward). Results: SOD1 severe mutation carriers show more frequent familial history for ALS and shorter survival compared to mild mutation carriers. Carriers and non-carriers of the p.H63D polymorphism did not differ in terms of sex ratio, frequency of positive familial history, age at onset, and bulbar/spinal ratio. In univariate and in Cox multivariable analysis using sex, age at onset, site of onset, family history, country of origin, and mutation severity as covariates, p.H63D carriers had a longer survival (p = 0.034 and p = 0.004). Conclusions: We found that SOD1-mutated ALS patients carrying the p.H63D HFE polymorphism have a longer survival compared to non-carriers, independently of sex, age and site of onset, family history, nation of origin, and severity of mutations, suggesting a possible role as disease progression modifier for the p.H63D HFE polymorphism in SOD1-ALS.

Lack of association between C282Y and H63D polymorphisms in the hemochromatosis gene and risk of multiple sclerosis: A meta-analysis.

Increasing evidence supports the potential role of iron metabolism in multiple sclerosis (MS). Previous studies examining the association between polymorphisms of the hemochromatosis gene (HFE) and susceptibility to MS have yielded inconsistent results. In the present study, a meta-analysis of 7 studies was performed conducted in populations of Caucasian origin using the Comprehensive Meta-analysis 3.0 software. The strength of association between the C282Y and H63D polymorphisms in HFE and MS risk was estimated by odds ratios with 95% confidence intervals. Cochran's Q statistic and I2 tests were applied to quantify heterogeneity between studies. An Egger's test was used to estimate publication bias. The C282Y and H63D polymorphisms had no significant association with increased MS risk (all P≥0.05) in the following genetic comparison models: Dominant model (YY + CY vs. CC or DD + HD vs. HH) and allele contrast (Y vs. C or D vs. H). No apparent publication bias or significant heterogeneity was found between studies. These results suggest that the HFE polymorphisms C282Y and H63D are not associated with susceptibility to MS in populations of Caucasian origin. Further studies should be performed in a larger series of MS patients to evaluate the contribution of HFE and other genetic variants associated with iron regulation in the development and progression of MS.

Evidence That HFE H63D Variant Is a Potential Disease Modifier in Cluster Headache.

Cluster headache (CH) is a primary headache disorder with a complex genetic background. Several studies indicate a potential link between iron homeostasis and the pathophysiology of primary headaches. The HFE gene encodes for a protein involved in iron metabolism, while genetic variants in HFE have been associated with hereditary hemochromatosis (HH), an iron overload disorder. The objective of the current study was to examine the association of the more common HFE H63D variant, with the susceptibility to develop CH and diverse clinical phenotypes in a population of Southeastern European Caucasian (SEC) origin. Genomic DNA samples from 128 CH patients and 294 neurologically healthy controls were genotyped for the HFE rs1799945 (H63D) variant. H63D genotypic and allelic frequency distribution did not differ significantly between patients and controls (p > 0.05). Subgroup analysis revealed a significantly more frequent occurrence of the variant G allele in chronic compared to episodic CH patients, indicative for a possible correlation of the HFE gene with the susceptibility for disease chronification. Although homozygosity for the less prevalent H63D variant G allele was minimal in the CH cohort, the results of the present study are in accordance with previous studies in CH and migraine patients, suggesting that HFE H63D variant modifies the disease clinical characteristics. Hence, despite the absence of a per se association with CH susceptibility in the current SEC cohort, variability in HFE gene may be potentially regarded as a disease modifier genetic factor in CH.