Insulin resistance-associated hepatic iron overload.

BACKGROUND & AIMS: Hepatic iron overload has been reported in various metabolic conditions, including the insulin-resistance syndrome (IRS) and nonalcoholic steatohepatitis (NASH). The aim of this study was to show that such hepatic iron overload is part of a unique and unrecognized entity. METHODS: A total of 161 non-C282Y-homozygous patients with unexplained hepatic iron overload were included. We determined the age; sex; presence of IRS (1 or more of the following: body mass index of >25, diabetes, or hyperlipidemia); serum iron tests and liver iron concentration (LIC; reference value, <36 micromol/g); liver function test results; C282Y and H63D HFE mutations; and liver histological status. RESULTS: Patients were predominantly male and middle-aged. Most (94%) had IRS. Transferrin saturation was increased in 35% (median, 42%; range, 13%-94%). LIC ranged from 38 to 332 micromol/g (median, 90 micromol/g), and LIC/age ratio ranged from 0.5 to 4.8 (median, 1.8). Allelic frequencies of both HFE mutations were significantly increased compared with values in normal controls (C282Y, 20% vs. 9%; H63D, 30% vs. 17%), only because of a higher prevalence of compound heterozygotes. Patients with no HFE mutations had similar degrees of iron overload as those with other genotypes, except for compound heterozygotes, who had slightly more iron burden. Steatosis was present in 25% of patients and NASH in 27%. Portal fibrosis (grades 0-3) was present in 62% of patients (grade 2 or 3 in 12%) in association with steatosis, inflammation, and increased age. Sex ratio, IRS, transferrin saturation, and LIC did not vary with liver damage. Serum ferritin concentration, liver function test results, and fibrosis grade were more elevated in patients with steatosis and NASH than in others, but LIC and allelic frequencies of HFE mutations were similar. CONCLUSIONS: This study shows that patients with unexplained hepatic iron overload are characterized by a mild to moderate iron burden and the nearly constant association of an IRS irrespective of liver damage.     

HFE mutations,hepatic iron,and fibrosis: ethnic-specific association of NASH with C282Y but not with fibrotic severity

There is conflicting evidence regarding inheritance of hemochromatosis gene (HFE) mutations and influence of hepatic iron deposition as cofactors for development of fibrosis in patients with nonalcoholic steatohepatitis (NASH). We studied hepatic iron content (Perls' stain grade), frequency of HFE mutations, and serum iron indices in 93 patients with NASH from a multiethnic background; 59 (63%) were of Anglo-Celtic origin. Data on C282Y mutations were available for all 93 patients and on H63D for 69 patients. Respective controls were 206 (for C282Y, 141 [69%] of whom were Anglo-Celtic) and 180 (for H63D) blood donors. Hyperferritinemia was present in 38 patients (40%) with NASH, but transferrin saturation was increased (>55%) in only 5 (5%). Liver biopsy specimens showed advanced fibrosis in 31 (33%) (cirrhosis in 20%). Altogether, 9 biopsy specimens (10%) showed increased iron: 7 (8%) with grade 2 and 2 (2%) with grade 3 iron staining. Only 1 biopsy specimen with increased iron showed advanced fibrosis. The frequency of C282Y heterozygosity was increased in Anglo-Celtic patients with NASH compared with ethnic blood donor controls (22% vs. 9.2%; P =.035); there were no C282Y homozygotes in the NASH cohort. Although there was a trend toward higher serum ferritin levels among C282Y heterozygotes with NASH, there were no differences in histologic grades of steatosis, inflammation, or fibrosis between individuals with and without C282Y. The frequencies of compound C282Y/H63D heterozygotes (n = 1) or H63D heterozygotes (n = 10) were not increased in NASH. Multivariate analysis identified female sex, diabetes mellitus, and more severe liver inflammation but not HFE mutations, serum ferritin, iron saturation, or hepatic iron staining as independent predictors of hepatic fibrosis. In conclusion, hepatic iron is not a factor linked to hepatic fibrogenesis in patients with NASH. HFE mutations do not confer an additional risk of hepatic fibrosis in this disorder.     

Interaction of iron,insulin resistance,and nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) has emerged as a ubiquitous liver disorder with occasional serious overtones. Although diabetes and obesity were initially held culpable, insulin resistance (IR) is now considered the fundamental operative mechanism. IR is probably the "first step" in nonalcoholic steatohepatitis (NASH). Oxidative stress may be the elusive "second" of possibly multiple steps in the progression of steatosis to fibrosing steatohepatitis. Because hepatic iron promotes oxidative stress, it was mooted as a contributory cofactor in NASH. This proposal was strengthened by an association with hepatic fibrosis. Subsequent studies have shown neither a significant increase in hepatic iron nor an association between hepatic iron and any of the histologic determinants in NASH. Likewise, the increased prevalence of hemochromatosis gene (HFE) mutations in some studies appears to be largely irrelevant to the development of hepatic fibrosis. Excess hepatic iron may occur in insulin resistance-associated iron overload (IRHIO), characterized by hyperferritinemia with normal to mild increases in transferrin saturation. Although patients with IRHIO have a high prevalence of IR-related metabolic disorders, the relationship of IRHIO to NASH is unclear. A recent study showed improvement in insulin sensitivity with the use of venesection in patients with NAFLD, but this approach cannot be implemented without extensive review.     

Relative contribution of iron burden, HFE mutations, and insulin resistance to fibrosis in nonalcoholic fatty liver

The mechanism(s) determining the progression from fatty liver to steatohepatitis is currently unknown. Our goal was to define the relative impact of iron overload, genetic mutations of HFE, and insulin resistance on the severity of liver fibrosis in a population of subjects with nonalcoholic fatty liver disease (NAFLD) who had low prevalence of obesity and no overt symptoms of diabetes. In a cohort of 263 prospectively enrolled patients with NAFLD, 7.4% of patients had signs of peripheral iron overload and 9% had signs of hepatic iron overload, but 21.1% had hyperferritinemia. The prevalence of C282Y and H63D HFE mutations was similar to the general population and mutations were not associated with iron overload. Although subjects were on average only moderately overweight, insulin sensitivity, measured both in the fasting state and in response to oral glucose, was lower. Univariate analysis demonstrated that the presence of severe fibrosis was independently associated with older age, female sex, overweight, aspartate/alanine aminotransferase ratio, serum ferritin level, fasting glucose and insulin levels, decreased insulin sensitivity, and with histologic features (degree of necroinflammation and steatosis). After adjustment for body mass index (BMI), age, sex, and degree of steatosis, ferritin levels (odds ratio [OR] = 1.77; 95% CI = 1.21- 2.58; P =.0032) and the oral glucose insulin sensitivity (OR = 0.53; CI = 0.33-0.87; P =.0113) were independent predictors of severe fibrosis. In conclusion, the current study indicates that insulin resistance is a major, independent risk factor for advanced fibrosis in patients with NAFLD. Increased ferritin levels are markers of severe histologic damage, but not of iron overload. Iron burden and HFE mutations do not contribute significantly to hepatic fibrosis in the majority of patients with NAFLD.     

Serum Ferritin Is a Clinical Biomarker in Japanese Patients with Nonalcoholic Steatohepatitis (NASH) Independent of HFE Gene Mutation

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver injury. The spectrum of NAFLD is broad, extending from simple steatosis through nonalcoholic steatohepatitis (NASH). Iron is regarded as a putative element that interacts with oxygen radicals, and high rates of hyperferritinemia and increased hepatic iron stores have been demonstrated in NASH. We investigated serum ferritin concentrations, HFE gene mutations, and insulin resistance in Japanese NASH patients and the diagnostic utility of serum ferritin concentrations as a means of distinguishing NASH. Serum ferritin concentrations were measured in 86 patients with histopathologically verified NAFLD (24 with steatosis and 62 with NASH) and 20 control subjects, they were tested for HFE gene mutations and their insulin resistance was measured. The serum ferritin concentration was significantly higher in the NASH patients than in the patients with simple steatosis (P = 0.006). There was no significant difference between the groups in HFE gene mutation (C282Y, H63D, and S65C), and the serum ferritin level was related with insulin resistance. The area under the ROC curve was 0.732 for distinguishing NASH from simple steatosis (P = 0.005; 95% CI, 0.596–0.856). In conclusion high serum ferritin concentrations are a distinguishing feature of Japanese NASH patients independent of HFE gene mutations.     

Nonalcoholic steatohepatitis in Asian Indians is neither associated with iron overload nor with HFE gene mutations

AIM: The pathogenesis of occurrence of liver inflammation and fibrosis in patients with nonalcoholic steatohepatitis (NASH) is not completely understood. Other than insulin resistance, iron abnormalities have been thought to be one of the triggering factors. Therefore, our aim was to study the role of iron abnormalities and HFE gene mutations in patients with NASH. METHODS: Thirty-one patients of NASH diagnosed on the basis of clinical examination biochemistry, ultrasonography and liver biopsy (n = 14) were included in the study. Serum iron parameters (n = 23) (iron, ferritin, total iron-binding capacity and transferrin saturation), Perls' iron staining on liver biopsies (n = 14) and HFE gene mutations (C282Y and H63D) (n = 16) were studied in these patients. The association between iron staining, necroinflammatory activity and fibrosis stage on liver biopsies was also determined. RESULTS: Elevated serum iron, ferritin and transferrin saturation above 55% were observed in 4.3% of patients. On histology, 71% of the patients had negative iron staining, 21.4% had 1+ staining, 7.2% had 2+ staining and none had 3+ or 4+ staining. There was no association between the degree of iron staining and necroinflammatory activity (P=0.55) and fibrosis stage (P= 0.09) on histology. None of the patients had C282Y HFE gene mutation and four patients (25%) were found to be heterozygotes for H63D gene mutation. CONCLUSION: Our study does not favor iron overload and HFE gene mutations as major factors in the pathogenesis of NASH in Asian Indians.     

Revaluation of clinical and histological criteria for diagnosis of dysrnetabolic iron overload syndrome

AIM: To re-evaluate the diagnostic criteria of insulin resistance hepatic iron overload based on clinical,biochemical and histopathological findings.METHODS: We studied 81 patients with hepatic iron overload not explained by known genetic and acquired causes.The metabolic syndrome (MS) was defined according to ATPⅢ criteria.Iron overload was assessed by liver biopsy.Liver histology was evaluated by Ishak's score and iron accumulation by Deugnier's score; steatosis was diagnosed when present in ≥ 5% of hepatocytes.RESULTS: According to transferrin saturation levels,we observed significant differences in the amount of hepatic iron overload and iron distribution,as well as the number of metabolic abnormalities.Using Receiving Operating Curve analysis,we found that the presence of two components of the MS differentiated two groups with a statistically significant different hepatic iron overload (P ＜ 0.0001).Patients with ≥ 2 metabolic alterations and steatosis had lower amount of hepatic iron,lower transferrin saturation and higher sinusoidal iron than patients with ＜ 2 MS components and absence of steatosis.CONCLUSION: In our patients,the presence of ≥2 alterations of the MS and hepatic steatosis was associated with a moderate form of iron overload with a prevalent sinusoidal distribution and a normal transferrin saturation,suggesting the existence of a peculiar pathogenetic mechanism of iron accumulation.These patients may have the typical dysmetabolic iron overload syndrome.By contrast,patients with transferrin saturation ≥ 60% had more severe iron overload,few or no metabolic abnormalities and a hemochromatosis-like pattern of iron overload.     

Revaluation of clinical and histological criteria for diagnosis of dysmetabolic iron overload syndrome

AIM： To re-evaluate the diagnostic criteria of insulin resistance hepatic iron overload based on clinical, biochemical and histopathological findings. METHODS： We studied 81 patients with hepatic iron overload not explained by known genetic and acquired causes. The metabolic syndrome （MS） was defined according to ATPⅢ criteria. Iron overload was assessed by liver biopsy. Liver histology was evaluated by Ishak＇s score and iron accumulation by Deugnier＇s score; steatosis was diagnosed when present in ≥ 5% of hepatooltes. RESULTS： According to transferrin saturation levels, we observed significant differences in the amount of hepatic iron overload and iron distribution, as well as the number of metabolic abnormalities. Using Receiving Operating Curve analysis, we found that the presence of two components of the MS differentiated two groups with a statistically significant different hepatic iron overload （P 〈 0.0001）. Patients with ≥2 metabolic alterations and steatosis had lower amount of hepatic iron, lower transferrin saturation and higher sinusoidal iron than patients with 〈 2 MS components and absence of steatosis. CONCLUSION： In our patients, the presence of ≥ 2 alterations of the MS and hepatic steatosis was associated with a moderate form of iron overload with a prevalent sinusoidal distribution and a normal transferrin saturation, suggesting the existence of a peculiar pathogenetic mechanism of iron accumulation. These patients may have the typical dysmetabolic iron overload syndrome. By contrast, patients with transferrin saturation ≥ 60% had more severe iron overload, few or no metabolic abnormalities and a hemochromatosis-like pattern of iron overload.     

Non-alcoholic steatohepatitis and iron: increased prevalence of mutations of the HFE gene in non-alcoholic steatohepatitis.

BACKGROUND/AIMS: Non-alcoholic steatohepatitis (NASH) is increasingly recognized, and its pathogenesis is believed to involve increased oxidative stress. Elevated levels of serum ferritin and positive liver iron stains are often observed in patients with NASH, and the pathogenesis of liver injury due to iron is also thought to involve oxidative stress. The aim of this study was to determine whether there is an association of NASH and mutations in the HFE gene associated with hereditary hemochromatosis (HHC). METHODS: Clinical, laboratory, and histopathological data on all 57 subjects with a final diagnosis of NASH seen between August 1990 and August 1997 at our Liver Center were analyzed. Thirty-six Caucasian subjects (23 men) with NASH underwent mutational analyses of HFE gene mutations performed. The prevalence of HFE gene mutations was compared to that in 348 Caucasian normal controls. Data were analyzed by both parameteric and non-parametric methods with similar results. RESULTS: One subject (2.8%) with NASH was homozygous for the C282Y mutation and six (16.7%) were heterozygous, compared with 0%, and 11.2%, respectively, of controls. Two (5.6%) subjects with NASH were homozygous for the H63D mutation and 16 (44.4%) were heterozygous, whereas 2.9% and 26.4%, respectively, of controls had these genotypes. The prevalence of heterozygosity (61.1%) for either mutation was significantly higher in subjects with NASH than in controls (38%) (p = 0.008), and the prevalence of homozygosity or heterozygosity combined in NASH subjects (69.4%) was significantly higher than for controls (40.5%, p = 0.001). Sex (63-67% male) and age at diagnosis of NASH did not differ between those with or without HFE mutations, but men with NASH were significantly more likely than women to have the H63D mutation (15/23 vs. 3/13, p<0.05) Levels of serum ferritin, iron, transferrin saturation levels, and the degree of hepatic iron staining were significantly higher (p<0.05) in subjects with NASH who carried an HFE mutation than in those without. Differences in hepatic iron concentrations or hepatic iron indices between NASH subjects with and without HFE mutations were not significant. Those with C282Y mutations had significantly more hepatic fibrosis than those without (p<0.05). Those with HFE mutations had significantly higher levels of serum ALT (90+/-11 [mean +/- SE]) than those without (55+/-6; p = 0.02). CONCLUSION: The prevalences of the HFE gene mutations associated with hereditary hemochromatosis are increased among North American subjects with NASH.     

Mild iron overload in patients carrying the HFE S65C gene mutation: a retrospective study in patients with suspected iron overload and healthy controls

BACKGROUND AND AIMS: The role of the HFE S65C mutation in the development of hepatic iron overload is unknown. The aim of the present study was: (A) to determine the HFE S65C frequency in a Northern European population; and (B) to evaluate whether the presence of the HFE S65C mutation would result in a significant hepatic iron overload. PATIENTS AND METHODS: Biochemical iron parameters and HFE mutation analysis (for the C282Y, H63D, and S65C mutations) were analysed in 250 healthy control subjects and collected retrospectively in 296 patients with suspected iron overload (elevated serum ferritin and/or transferrin saturation). The frequency of patients having at least mild iron overload, and mean serum ferritin and transferrin saturation values were calculated for each HFE genotype. For patients carrying the S65C mutation, clinical data, liver biopsy results, and amount of blood removed at phlebotomy were determined. RESULTS: The HFE S65C mutation was found in 14 patients and eight controls. In controls, the S65C allele frequency was 1.6%. The S65C allele frequency was enriched in non-C282Y non-H63D chromosomes from patients (4.9%) compared with controls (1.9%) (p<0.05). Serum ferritin was significantly increased in controls carrying the S65C mutation compared with those without HFE mutations. Fifty per cent of controls and relatives having the S65C mutation had elevated serum ferritin levels or transferrin saturation. The number of iron overloaded patients was significantly higher among those having HFE S65C compared with those without any HFE mutation. Half of patients carrying the S65C mutation (7/14) had evidence of mild or moderate hepatic iron overload but no signs of extensive fibrosis in liver biopsies. Screening of relatives revealed one S65C homozygote who had no signs of iron overload. Compound heterozygosity with S65C and C282Y or H63D did not significantly increase the risk of iron overload compared with S65C heterozygosity alone. CONCLUSIONS: The HFE S65C mutation may lead to mild to moderate hepatic iron overload but neither clinically manifest haemochromatosis nor iron associated extensive liver fibrosis was encountered in any of the patients carrying this mutation.     

Genetic and metabolic factors are associated with increased hepatic iron stores in a selected population of p.Cys282Tyr heterozygotes

Heterozygosity for p.Cys282YTyr is not ordinarily associated with a hemochromatosis phenotype, unless associated in the compound heterozygous state with other HFE mutations. The aims of the study were to identify factors responsible for iron overload in patients who were only heterozygous for p.Cys282Tyr at first genetic testing. Since 2001, twelve p.Cys282Tyr heterozygous patients with iron overload, defined by increased transferrin saturation, serum ferritin and hepatic iron stores, were identified. Four patients showed rare nonsense or missense HFE mutations in the compound heterozygous state with p.Cys282Tyr. One mutation (p.Gln233X) was never described before. The other 8 patients did not carry any other causal mutations in iron-related genes, but showed a very high prevalence of hepatic steatosis and steato-hepatitis, and metabolic alterations. Serum ferritin levels did not differ between the two groups, but transferrin saturation, hepatic iron amount and distribution significantly did. These last indices should be then strongly considered to decide for additional genetic characterization in p.Cys282Tyr heterozygotes. Our results also highlights the influence of metabolic alterations on serum iron indices and pattern of hepatic iron accumulation.     

Dysmetabolic hyperferritinemia is associated with normal transferrin saturation,mild hepatic iron overload,and elevated hepcidin

Hyperferritinemia is common in individuals with the metabolic syndrome (dysmetabolic hyperferritinemia), but its pathophysiology and the degree to which it reflects tissue iron overload remains unclear. We conducted a cross-sectional study evaluating ten cases with dysmetabolic hyperferritinemia for liver iron overload and compared their serum iron indices and urine hepcidin levels to healthy controls. Seven out of ten cases had mild hepatic iron overload by magnetic resonance imaging (MRI) (median, 75 μmol/g dry weight). Cases had higher serum ferritin than controls (median, 672 μg/L vs. 105 μg/L, p < 0.001), but the median transferrin saturation was not significantly different (38% vs. 36%, p = 0.5). Urinary hepcidin was elevated in dysmetabolic hyperferritinemia (median; 1,584 ng/mg of creatinine vs. 799 ng/mg of creatinine, p = 0.05). Dysmetabolic hyperferritinemia is characterized by hyperferritinemia with normal transferrin saturation, elevated hepcidin levels, and mild liver iron overload in a subset of patients.     

Alterations in lipid, carbohydrate and iron metabolism in patients with non-alcoholic steatohepatitis (NASH) and metabolic syndrome

Background

NASH (non-alcoholic steatohepatitis) is considered the hepatic manifestation of the metabolic syndrome (MS). We aimed to analyze lipid, carbohydrate, and iron metabolism in NASH.

Patients, methods

37 patients with MS (17 M/20 F, 51 +/− 15 years), elevated transaminases; 25 patients had histologically proven NASH (NAS score ≥ 5), 12 patients had toxic background (nonNASH). 37 age, sex, BMI-matched healthy controls.Lipid variables, LDL-subfractions, iron, ferritin, transferrin (T), transferrin saturation (TS), and hepcidin (H) were measured in patients/controls. Oral glucose tolerance tests were performed.

Results

NASH patients with steatosis gr. 2 and 3 (> 33% hepatic fat) had higher sd-LDL (mg/dl) concentrations than patients with steatosis gr. 1 (< 33%) (p = 0.002), nonNASH patients (p = 0.03) and controls (p = 0.001). Sd absolute (mg/dl) correlated directly with the steatosis grade only in patients with NASH and steatosis > 33% (p = 0.04).NASH-patients showed higher insulin, C-peptide and IRI values than nonNASH patients (p = 0.034; 0.032; 0.04).H was increased in patients versus controls (p < 0.001). H correlated with ferritin in MS-patients (p = 0.01), correlated directly with sd-LDL (mg/dl) (p = 0.017) and IRI (p < 0.001) and indirectly with HDL (p = 0.05) in NASH. No associations between hepatic inflammation/iron content on liver biopsy and variables of lipid metabolism were found but hepcidin correlated with hepatic inflammation in all patients and with NAS scores in NASH.

Conclusions

NASH-patients show insulin resistance and increased sd-LDL subfractions, suggesting an atherogenic profile. The correlation of H with sd-LDL and IRI, without relation to hepatic iron content suggests a putative link between inflammation, carbohydrate and lipid metabolism in NASH.     

Frequency of primary iron overload and HFE gene mutations （C282Y, H63D and S65C） in chronic liver disease patients in north India

AIM:To identify the frequency of iron overload and study the three mutations in the HFE gene (C282Y,H63D,and S65C) in patients with chronic liver disorders (CLD) and controls. METHODS:To identify patients with iron overload (transferrin saturation > 45% in females and > 50% in males and serum ferritin > 1000 ng/mL) we evaluated 236 patients with CLD,including 59 with non-alcoholic steatohepatitis (NASH),22 with alcoholic liver disease (ALD),19 of cirrhosis due to viruses (HBV,HCV),and 136 with cryptogenic cirrhosis. Mutations of the HFE gene were analyzed by PCR-RE. hundred controls were screened for iron status and the mutations. RESULTS:Seventeen patients with CLD showed evidence of iron overload. Fifteen cases of iron overload had cryptogenic cirrhosis and two had ALD. None of the controls showed iron overload. We did not find any individual with 282Y or 65C either in the cases or in the controls. The prevalence of H63D heterozygosity was 12% in normal individuals,14.8% in 236 patients (16.9% in NASH,13.6% in ALD,26.3% in viral and 12.5% in cryptogenic cirrhosis) and the overall prevalence was 13.98%. Only two of the 17 patients with primary iron overload were heterozygous for H63D. One patient with NASH and one normal individual who were homozygous for H63D showed no iron overload.CONCLUSION:Primary iron overload in Indians is nonHFE type,which is different from that in Europeans and further molecular studies are required to determine the defect in various iron regulatory genes.     

Iron status and HFE genotype in erythrocyte pyruvate kinase deficiency: study of Italian cases

We evaluated the iron status and searched for mutations C282Y and H63D in the hereditary hemochromatosis gene (HFE) in 34 pyruvate kinase (PK)-deficient patients from 29 unrelated families. Nine had received multiple transfusions. Thirteen of the 25 nontransfused patients displayed increased serum ferritin concentration, in the absence of conditions known to raise this parameter. HFE genotype was abnormal in 9 of 34 patients. The allele frequency was 1.8% for mutation 845G--> (C282Y) and 16.1% for mutation 187C-->G (H63D). Nontransfused subjects with abnormal genotype had serum ferritin and transferrin saturation values significantly higher than those with wild-type genotype. Of the 12 adult nontransfused patients with increased iron status parameters, 1 was C282Y homozygous, 1 compound heterozygous for C282Y and H63D, 3 H63D heterozygous, and 7 had a normal HFE genotype. Serum ferritin and transferrin saturation were not related to hemoglobin, reticulocytes, and bilirubin concentration. At multivariate analysis serum ferritin was independently associated with age and gender, but not with splenectomy and HFE genotypes. The retrospective evaluation of the iron status profile of 10 patients (3 with abnormal and 7 with wild-type HFE genotype) with at least 10 years follow-up showed that overt iron accumulation requiring iron chelation had occurred only in the 3 patients (2 of whom were splenectomized) with the mutated HFE gene.     

The effect of HFE genotypes on measurements of iron overload in patients attending a health appraisal clinic

BACKGROUND: The gene that causes most cases of hereditary hemochromatosis is designated HFE. Three mutations exist at this locus at a relatively high gene frequency. OBJECTIVE: To determine the gene frequency of the three HFE mutations and to relate genotypes to various clinical and laboratory variables. DESIGN: Observational study. SETTING: Health appraisal clinic. PATIENTS: 10,198 adults who registered for health appraisal and consented to DNA examination for hemochromatosis. Consenting patients were slightly older and had attained a slightly higher educational level than nonconsenting patients. MEASUREMENTS: Extensive medical history and laboratory tests, including complete blood count, transferrin saturation, and other chemistries; serum ferritin levels; and HFE genotype. RESULTS: In white participants, the gene frequencies were 0.063 for the C282Y mutation, 0.152 for the H63D mutation, and 0.016 for the S65C mutation. Gene frequencies were lower in other ethnic groups. In participants with HFE mutations, the average serum transferrin saturation and ferritin levels were slightly increased, as were mean hemoglobin levels and mean corpuscular volume. A transferrin saturation of 50% had a sensitivity of only 0.52 (95% CI, 0.345 to 0.686) and a specificity of 0.908 (CI, 0.902 to 0.914) for detection of homozygosity. A ferritin level of 200 microg/L in women and 250 microg/L in men had a sensitivity of 0.70 (CI, 0.540 to 0.854) and a specificity of 0.803 (CI, 0.796 to 0.811). The prevalence of iron deficiency anemia was lower in women who carried HFE mutations. CONCLUSIONS: Screening for transferrin saturation and ferritin levels does not detect all homozygotes for the major hemochromatosis mutation. Heterozygotes for HFE mutations had a lower prevalence of iron deficiency anemia.     

Clinical characteristics of type 2 diabetes in patients with mutations of HFE

Genetic hemochromatosis (GH) is associated with two mutations of the HFE gene (Cys282Tyr and His63Asp). Heterozygosity for GH is associated with a mild increase in iron metabolism parameters, and increased iron stores are associated with abnormal glucose tolerance and decreased insulin sensitivity in the general population. We have previously shown that the frequency of the two HFE mutations is not increased in patients with type 2 diabetes. However, to assess whether the presence of HFE mutations modulates the clinical presentation of type 2 diabetes, we studied the clinical characteristics and iron metabolism indexes according to the presence of the two mutations in 266 patients with type 2 diabetes. The Cys282Tyr mutation and the His63Asp mutation were present in 9. 8% and 26% of the patients, respectively. Serum iron, transferrin saturation and ferritin concentrations were significantly increased in patients expressing either HFE mutations, compared to those without any mutation. There was no difference in the clinical characteristics in the two groups except that obesity was significantly less frequent in the patients with at least one mutation than in those without any mutation (27.6% vs 42.8%, p=0.02). This finding suggests that, in the absence of obesity, HFE mutations, through the insulin resistance associated with the increase in iron stores, may contribute to the onset of type 2 diabetes.     

Alpha 1-antitrypsin mutations in NAFLD: high prevalence and association with altered iron metabolism but not with liver damage

Hyperferritinemia, a common feature of nonalcoholic fatty liver disease (NAFLD), has been associated with steatohepatitis and fibrosis. Heterozygosity for alpha 1-antitrypsin (AAT) mutations is a cofactor of liver damage, and AAT influences inflammation and iron metabolism. This study evaluated the prevalence of the common AAT PiS/PiZ mutants in 353 patients with NAFLD, 195 of whom had hyperferritinemia, versus 114 matched controls and their influence on iron metabolism and the severity of liver damage in the 212 patients submitted to biopsy. PiS and PiZ alleles were searched for by restriction analysis. Thirty-eight patients (10.8%) carried non-MM genotypes versus 4/114 (3.5%) controls (P = .02). Patients carrying AAT mutations had higher ferritin (573 [454-966] vs. 348 [201-648]; P = .001) with similar transferrin saturation. The difference was more evident in males (P < .0001) and significant in patients not carrying HFE genotypes associated with iron overload (P = .015). The prevalence of non-MM genotypes was higher in patients with hyperferritinemia than in those without (28/195, 14% vs. 10/158, 6%, P = .016), and AAT mutations were associated with higher prevalence of sinusoidal siderosis (17/27, 63% vs. 70/180, 39%; P = .02), and sinusoidal/total iron score (46.3 +/- 38% vs. 25.1 +/- 35%, P = .01). Although ferritin was independently associated with fibrosis (P = .047), AAT mutations favoring sinusoidal iron deposition did not affect liver damage. In conclusion, AAT mutations are associated with hyperferritinemia and sinusoidal iron accumulation, but not with more severe liver damage in NAFLD.     

HFE C282Y mutations are associated with advanced hepatic fibrosis in Caucasians with nonalcoholic steatohepatitis

Previous studies examining the relationship between HFE mutations and severity of nonalcoholic steatohepatitis (NASH) have been limited by small sample size or ascertainment bias. The aim of this study was to examine the relationship between HFE mutations and histological severity in a large North American multicenter cohort with NASH. Data from 126 NASH patients were collected from 6 North American centers. Liver biopsy and genotyping for the C282Y and H63D HFE mutations were performed in all subjects. Serum transferrin-iron saturation and ferritin levels as well as hepatic iron content were recorded whenever available. Univariate and multivariate logistic regression analyses were performed to identify factors associated with advanced hepatic fibrosis. The prevalence of heterozygous C282Y and H63D HFE mutations was 14.3% and 21.4%, respectively, in the overall cohort. Among Caucasians, C282Y heterozygotes were more likely to have bridging fibrosis or cirrhosis (44% versus 21% [P = 0.05]) and stainable hepatic iron (50% versus 16% [P = 0.011]) compared with patients with other genotypes. Diabetes mellitus was the only independent predictor of advanced hepatic fibrosis (OR 4.37, 95% CI 1.41-13.54 [P = 0.010]) using multiple logistic regression analysis adjusting for age, sex, ethnicity, body mass index, and HFE genotype status. CONCLUSION: The HFE C282Y heterozygous mutation is associated with advanced fibrosis among Caucasians with NASH. Additional studies are warranted to examine the possible mechanisms for this relationship.