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Objective: We evaluated the associations of self-reported diabetes with serum ferritin concentration, transferrin saturation (TfSat), and HFE C282Y and H63D mutations in six racial/ethnic groups recruited at five field centers in the Hemochromatosis and Iron Overload Screening (HEIRS) study. Research Design and Methods: Analyses were conducted on 97,470 participants. Participants who reported a previous diagnosis of diabetes and/or hemochromatosis or iron overload were compared with participants who did not report a previous diagnosis. Results: The overall prevalence of diabetes was 13.8%; the highest prevalence was in Pacific Islanders (20.1%). Of all participants with diabetes, 2.0% reported that they also had hemochromatosis or iron overload. The mean serum ferritin concentration was significantly greater in women with diabetes in all racial/ethnic groups and in Native-American men with diabetes than in those without diabetes. The mean serum ferritin concentration was significantly lower in Asian men with diabetes than in those without diabetes. Mean TfSat was lower in participants with diabetes from all racial/ethnic groups except Native-American women than in those without diabetes. There was no significant association of diabetes with HFE genotype. The mean serum ferritin concentration was greater (P < 0.0001) in women with diabetes than in those without diabetes for HFE genotypes except C282Y/C282Y and C282Y/H63D. Log serum ferritin concentration was significantly associated with diabetes in a logistic regression analysis after adjusting for age, sex, racial/ethnic group, HFE genotype, and field center. Conclusions: Serum ferritin concentration is associated with diabetes, even at levels below those typically associated with hemochromatosis or iron overload. [ABSTRACT FROM AUTHOR]

Background: Iron overload and hemochromatosis are common, treatable conditions. HFE genotypes, levels of serum ferritin, transferrin saturation values, and self-reported medical history were studied in a multiethnic primary care population. Methods: Participants were recruited from primary care practices and blood-drawing laboratories. Blood samples were tested for transferrin saturation, serum ferritin, and C282Y and H63D mutations of the HFE gene. Before genetic screening, participants were asked whether they had a history of medical conditions related to iron overload. Results: Of the 99,711 participants, 299 were homozygous for the C282Y mutation. The estimated prevalence of C282Y homozygotes was higher in non-Hispanic whites (0.44 percent) than in Native Americans (0.11 percent), Hispanics (0.027 percent), blacks (0.014 percent), Pacific Islanders (0.012 percent), or Asians (0.000039 percent). Among participants who were homozygous for the C282Y mutation but in whom iron overload had not been diagnosed (227 participants), serum ferritin levels were greater than 300 mug per liter in 78 of 89 men (88 percent) and greater than 200 microg per liter in 79 of 138 women (57 percent). Pacific Islanders and Asians had the highest geometric mean levels of serum ferritin and mean transferrin saturation despite having the lowest prevalence of C282Y homozygotes. There were 364 participants in whom iron overload had not been diagnosed (29 C282Y homozygotes) who had a serum ferritin level greater than 1000 microg per liter. Among men, C282Y homozygotes and compound heterozygotes were more likely to report a history of liver disease than were participants without HFE mutations. Conclusions: The C282Y mutation is most common in whites, and most C282Y homozygotes have elevations in serum ferritin levels and transferrin saturation. The C282Y mutation does not account for high mean serum ferritin levels and transferrin saturation values in nonwhites. [ABSTRACT FROM AUTHOR]

Background: In hemochromatosis, causes of abdominal pain and its associations with cirrhosis are poorly understood., Methods: We retrospectively compared characteristics of referred hemochromatosis probands with HFE p.C282Y homozygosity with/without biopsy-proven cirrhosis: sex, age, diabetes, heavy alcohol consumption, abdominal pain/tenderness, hepatomegaly, splenomegaly, non-alcoholic fatty liver disease, chronic viral hepatitis, ascites, transferrin saturation (TS), serum ferritin (SF), and iron removed by phlebotomy (QFe). We performed logistic regression on cirrhosis using characteristics identified in univariate comparisons. We performed computerized and manual searches to identify hemochromatosis case series and compiled prevalence data on cirrhosis and abdominal pain and causes of abdominal pain., Results: Of 219 probands, 57.1% were men. Mean age was 48±13 y. In 22 probands with cirrhosis, proportions of men, mean age, prevalences of heavy alcohol consumption, abdominal pain, abdominal tenderness, hepatomegaly, splenomegaly, and chronic viral hepatitis, and median TS, SF, and QFe were significantly greater than in probands without cirrhosis. Regression analysis revealed three associations with cirrhosis: abdominal pain (p = 0.0292; odds ratio 9.8 (95% CI: 1.2, 76.9)); chronic viral hepatitis (p = 0.0153; 11.5 (95% CI: 1.6, 83.3)); and QFe (p = 0.0009; 1.2 (95% CI: 1.1, 1.3)). Of eight probands with abdominal pain, five had cirrhosis and four had diabetes. One proband each with abdominal pain had heavy alcohol consumption, chronic viral hepatitis B, hepatic sarcoidosis, hepatocellular carcinoma, and chronic cholecystitis, cholelithiasis, and sigmoid diverticulitis. Abdominal pain was alleviated after phlebotomy alone in four probands. In 12 previous reports (1935-2011), there was a negative correlation of cirrhosis prevalence and publication year (p = 0.0033). In 11 previous reports (1935-1996), a positive association of abdominal pain prevalence and publication year was not significant (p = 0.0802)., Conclusions: Abdominal pain, chronic viral hepatitis, and QFe are significantly associated with cirrhosis in referred hemochromatosis probands with HFE p.C282Y homozygosity. Iron-related and non-iron-related factors contribute to the occurrence of abdominal pain., Competing Interests: The authors have declared that no competing interests exist.

Glyceronephosphate O-acyltransferase (GNPAT) p.D519G (rs11558492) was identified as a genetic modifier correlated with more severe iron overload in hemochromatosis through whole-exome sequencing of HFE p.C282Y homozygotes with extreme iron phenotypes. We studied the prevalence of p.D519G in HFE p.C282Y/p.H63D compound heterozygotes, a genotype associated with iron overload in some patients. Cases were Australian participants with elevated serum ferritin (SF) levels ≥300μg/L (males) and ≥200μg/L (females); subjects whose SF levels were below these cut-offs were designated as controls. Samples were genotyped for GNPAT p.D519G. We compared the allele frequency of the present subjects, with/without elevated SF, to p.D519G frequency in public datasets. GNPAT p.D519G was more prevalent in our cohort of p.C282Y/p.H63D compound heterozygotes with elevated SF (37%) than European public datasets: 1000G 21%, gnomAD 20% and ESP 21%. We conclude that GNPAT p.D519G is associated with elevated SF in Australian HFE p.C282Y/p.H63D compound heterozygotes., Competing Interests: Declaration of competing interest The authors declare no competing interests., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: Few cross-sectional studies report iron deficiency (ID) prevalence in women of different race/ethnicity and ages in US or Canada., Materials and Methods: We evaluated screening observations on women who participated between 2001-2003 in a cross-sectional, primary care-based sample of adults ages ≥25 y whose observations were complete: race/ethnicity; age; transferrin saturation; serum ferritin; and HFE p.C282Y and p.H63D alleles. We defined ID using a stringent criterion: combined transferrin saturation <10% and serum ferritin <33.7 pmol/L (<15 μg/L). We compared ID prevalence in women of different race/ethnicity subgrouped by age and determined associations of p.C282Y and p.H63D to ID overall, and to ID in women ages 25-44 y with or without self-reported pregnancy., Results: These 62,685 women included 27,079 whites, 17,272 blacks, 8,566 Hispanics, 7,615 Asians, 449 Pacific Islanders, 441 Native Americans, and 1,263 participants of other race/ethnicity. Proportions of women with ID were higher in Hispanics and blacks than whites and Asians. Prevalence of ID was significantly greater in women ages 25-54 y of all race/ethnicity groups than women ages ≥55 y of corresponding race/ethnicity. In women ages ≥55 y, ID prevalence did not differ significantly across race/ethnicity. p.C282Y and p.H63D prevalence did not differ significantly in women with or without ID, regardless of race/ethnicity, age subgroup, or pregnancy., Conclusions: ID prevalence was greater in Hispanic and black than white and Asian women ages 25-54 y. p.C282Y and p.H63D prevalence did not differ significantly in women with or without ID, regardless of race/ethnicity, age subgroup, or pregnancy., Competing Interests: The authors have declared that no competing interests exist.

Introduction and Aim: We sought to identify independent risk factors for cirrhosis in HFE p.C282Y homozygotes in a cross-sectional study., Material and Methods: We evaluated 368 p.C282Y homozygotes who underwent liver biopsy and compared characteristics of those with and without cirrhosis. We performed multivariable logistic regression on cirrhosis with: age; sex; race/ethnicity; diabetes; blood pints/units donated voluntarily; erythrocyte pints/units received; iron supplement use; alcohol intake, g/d; body mass index, kg/m2; swollen/tender 2nd/3rd metacarpophalangeal joints; elevated alanine aminotransferase; elevated aspartate aminotransferase; steatosis/fatty liver; iron removed by phlebotomy, g; and GNPAT p.D519G positivity., Results: Mean age of 368 participants (73.6% men) was 47 ± 13 (standard deviation) y. Cirrhosis was diagnosed in 86 participants (23.4%). Participants with cirrhosis had significantly greater mean age, proportion of men, diabetes prevalence, mean daily alcohol intake, prevalence of swollen/ tender 2nd/3rd metacarpophalangeal joints, mean serum ferritin, elevated alanine aminotransferase, elevated aspartate aminotransferase, and mean iron removed; and significantly fewer mean blood pints/units donated. GNPAT p.D519G positivity was detected in 82 of 188 participants (43.6%). In a multivariable model for cirrhosis, there were four significant positive associations: age (10-y intervals) (odds ratio 2.2 [95% confidence interval 1.5, 3.3]); diabetes (3.3; [1.1, 9.7]); alcohol intake (14 g alcohol drinks/d) (1.5 [1.2, 1.8]); and iron removed, g (1.3 [1.2, 1.4]). There was no statistical evidence of two-way interactions between these variables., Conclusion: In conclusion, cirrhosis in HFE p.C282Y homozygotes is significantly associated with age, diabetes, daily alcohol intake, and iron removed by phlebotomy, taking into account the effect of other variables.

Background: GNPAT p.D519G positivity is significantly increased in HFE p.C282Y homozygotes with markedly increased iron stores. We sought to determine associations of p.D519G and iron-related variables with iron stores in p.C282Y homozygotes., Methods: We defined markedly increased iron stores as serum ferritin >2247pmol/L (>1000μg/L) and either hepatic iron >236μmol/g dry weight or iron >10g by induction phlebotomy (men and women). We defined normal or mildly elevated iron stores as serum ferritin <674.1pmol/L (<300μg/L) or either age≥40y with iron ≤2.5g iron by induction phlebotomy or age≥50y with ≤3.0g iron by induction phlebotomy (men only). We compared participant subgroups using univariate methods. Using multivariable logistic regression, we evaluated associations of markedly increased iron stores with these variables: age; iron supplement use (dichotomous); whole blood units donated; erythrocyte units received as transfusion; daily alcohol consumption, g; and p.D519G positivity (heterozygosity or homozygosity)., Results: The mean age of 56 participants (94.6% men) was 55±10 (SD) y; 41 had markedly increased iron stores. Prevalences of swollen/tender 2nd/3rd metacarpophalangeal joints and elevated aspartate or alanine aminotransferase were significantly greater in participants with markedly increased iron stores. Only participants with markedly increased iron stores had cirrhosis. In multivariable analyses, p.D519G positivity was the only exposure variable significantly associated with markedly increased iron stores (odds ratio 9.9, 95% CI [1.6, 60.3], p=0.0126)., Conclusions: GNPAT p.D519G is strongly associated with markedly increased iron stores in p.C282Y homozygotes after correction for age, iron-related variables, and alcohol consumption., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Both familial and sporadic porphyria cutanea tarda (PCT) are iron dependent diseases. Symptoms of PCT resolve when iron stores are depleted by phlebotomy, and a sequence variant of HFE (C282Y, c.843G>A, rs1800562) that enhances iron aborption by reducing hepcidin expression is a risk factor for PCT. Recently, a polymorphic variant (D519G, c.1556A>G, rs11558492) of glyceronephosphate O-acyltransferase (GNPAT) was shown to be enriched in male patients with type I hereditary hemochromatosis (HFE C282Y homozygotes) who presented with a high iron phenotype, suggesting that GNPAT D519G, like HFE C282Y, is a modifier of iron homeostasis that favors iron absorption. To challenge this hypothesis, we investigated the frequency of GNPAT D519G in patients with both familial and sporadic PCT. Patients were screened for GNPAT D519G and allelic variants of HFE (both C282Y and H63D). Nucleotide sequencing of uroporphyrinogen decarboxylase (URO-D) identified mutant alleles. Patients with low erythrocyte URO-D activity or a damaging URO-D variant were classified as familial PCT (fPCT) and those with wild-type URO-D were classified as sporadic PCT (sPCT). GNPAT D519G was significantly enriched in the fPCT patient population (p = 0.0014) but not in the sPCT population (p = 0.4477). Both HFE C282Y and H63D (c.187C>G, rs1799945) were enriched in both PCT patient populations (p<0.0001) but showed no greater association with fPCT than with sPCT., Conclusion: GNPAT D519G is a risk factor for fPCT, but not for sPCT., Competing Interests: The authors have declared that no competing interests exist.

Unlabelled: To identify polymorphisms associated with variability of iron overload severity in HFE-associated hemochromatosis, we performed exome sequencing of DNA from 35 male HFE C282Y homozygotes with either markedly increased iron stores (n = 22; cases) or with normal or mildly increased iron stores (n = 13; controls). The 35 participants, residents of the United States, Canada, and Australia, reported no or light alcohol consumption. Sequencing data included 82,068 single-nucleotide variants, and 10,337 genes were tested for a difference between cases and controls. A variant in the GNPAT gene showed the most significant association with severe iron overload (P = 3 × 10(-6) ; P = 0.033 by the likelihood ratio test after correction for multiple comparisons). Sixteen of twenty-two participants with severe iron overload had glyceronephosphate O-acyltransferase (GNPAT) polymorphism p.D519G (rs11558492; 15 heterozygotes, one homozygote). No control participant had this polymorphism. To examine functional consequences of GNPAT deficiency, we performed small interfering RNA-based knockdown of GNPAT in the human liver-derived cell line, HepG2/C3A. This knockdown resulted in a >17-fold decrease in expression of the messenger RNA encoding the iron-regulatory hormone, hepcidin., Conclusion: GNPAT p.D519G is associated with a high-iron phenotype in HFE C282Y homozygotes and may participate in hepcidin regulation., (© 2015 by the American Association for the Study of Liver Diseases.)

We sought to examine the relationship between elevated transferrin saturation (TS) and measures of health status (telomere length and patient-reported health-related quality of life) to assess whether elevated TS is associated with negative patient outcomes beyond increased risk for morbidity and mortality, using a cross-sectional analysis of the Hemochromatosis and Iron Overload Screening Study supplemented with assays for leukocyte telomere length in adults ≥25 years old (n = 669). Among individuals with elevated TS (≥45 % for women and ≥50 % for men), who also had a usual source of care, only 5.2 % reported ever being told by a doctor that they had an elevated iron condition. In a fully adjusted general linear regression model controlling for demographic characteristics as well as health conditions associated with iron overload, elevated TS versus non-elevated TS was associated with worse general health status (60.4 vs. 63.8, P < 0.05), mental health status (76.5 vs. 82.2, P < 0.0001) and shorter telomere length (241.4 vs. 261.3, P < 0.05). Increased surveillance of elevated TS may be in order as elevated TS is associated with decreased health status and very few patients with elevated TS are aware of their condition.

Background & Aims: Celiac disease is an increasingly recognized disorder in Caucasian populations of European origin. Little is known about its prevalence in non-Caucasians. Although it is thought to be a cause of iron-deficiency anemia, little is known about the extent to which celiac disease contributes to iron deficiency in Caucasians, and especially non-Caucasians. We analyzed samples collected from participants in the Hemochromatosis and Iron Overload Screening study to identify individuals with iron deficiency and to assess the frequency of celiac disease., Methods: We analyzed serum samples from white men (≥25 y) and women (≥50 y) who participated in the Hemochromatosis and Iron Overload Screening study; cases were defined as individuals with iron deficiency (serum ferritin level, ≤12 μg/L) and controls were those without (serum ferritin level, >100 μg/L in men and >50 μg/L in women). All samples also were analyzed for human recombinant tissue transglutaminase immunoglobulin A; positive results were confirmed by an assay for endomysial antibodies. Patients with positive results from both celiac disease tests were presumed to have untreated celiac disease, and those with a positive result from only 1 test were excluded from analysis. We analyzed HLA genotypes and frequencies of celiac disease between Caucasians and non-Caucasians with iron deficiency., Results: Celiac disease occurred in 14 of 567 cases (2.5%) and in only 1 of 1136 controls (0.1%; Fisher exact test, P = 1.92 × 10(-6)). Celiac disease was more common in Caucasian cases (14 of 363; 4%) than non-Caucasian cases (0 of 204; P = .003). Only 1 Caucasian control and no non-Caucasian controls had celiac disease. The odds of celiac disease in individuals with iron deficiency was 28-fold (95% confidence interval, 3.7-212.8) that of controls; 13 of 14 cases with celiac disease carried the DQ2.5 variant of the HLA genotype., Conclusions: Celiac disease is associated with iron deficiency in Caucasians. Celiac disease is rare among non-Caucasians-even among individuals with features of celiac disease, such as iron deficiency. Celiac disease also is rare among individuals without iron deficiency. Men and postmenopausal women with iron deficiency should be tested for celiac disease., (Copyright © 2013 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Background: Many patients referred for an elevated serum ferritin level <1000 µg⁄L are advised that they likely have iron overload and hemochromatosis., Aims: To determine the prevalence of HFE mutations in the hemochromatosis gene for 11 serum ferritin concentration intervals from 200 µg⁄L to 1000 µg⁄L in Caucasian participants in a primary care, population-based study., Methods: The Hemochromatosis and Iron Overload Screening study screened 99,711 participants for serum ferritin levels, transferrin saturation and genetic testing for the C282Y and H63D mutations of the HFE gene. This analysis was confined to 17,160 male and 27,465 female Caucasian participants because the HFE C282Y mutation is rare in other races. Post-test likelihood was calculated for prediction of C282Y homozygosity from a ferritin interval. A subgroup analysis was performed in participants with both an elevated serum ferritin level and transferrin saturation., Results: There were 3359 male and 2416 female participants with an elevated serum ferritin level (200 µg⁄L to 1000 µg⁄L for women, 300 µg⁄L to 1000 µg⁄L for men). There were 69 male (2.1%) and 87 female (3.6%) C282Y homozygotes, and the probability of being a homozygote increased as the ferritin level increased. Post-test likelihood values were 0.3% to 16% in men and 0.3% to 30.4% in women., Conclusions: Iron loading HFE mutations are unlikely to be the most common cause of an elevated serum ferritin level in patients with mild hyperferritinemia. Patients should be advised that there are many causes of an elevated serum ferritin level including iron overload.

Elevated body iron stores are associated with morbidity and mortality due to oxidative stress. Hereditary hemochromatosis, a common condition caused by HFE gene mutations, can lead to excess iron storage and disease but clinical penetrance of HFE gene mutations is low and many people with elevated iron stores lack HFE mutations. We analyzed data from the Hemochromatosis and Iron Overload Screening Study to assess the relationship among HFE genotype (individuals with either homozygous or compound heterozygous status for C282Y and/or H63D HFE mutations were defined as genotype positive, or G+), elevated iron phenotype (individuals exceeding gender-specific transferrin saturation and serum ferritin threshold levels were considered phenotype positive, or P+), and leukocyte telomere length, a marker of biological aging and cumulative oxidative stress. In unadjusted analyses in comparison to individuals who were G-P-, G+P- were not significantly different (OR 0.74; 95% CI 0.26-2.04), while the G+P+ (OR 2.03; 95% CI 1.15-3.56), and G-P+ (OR 2.24; 95% CI 1.5-3.29) had increased risk of short telomeres (<=25th percentile) rather than long telomeres (>=75th percentile). In analyses adjusting for age, gender, and race/ethnicity, the effect of individuals with elevated iron phenotypes having short telomeres persisted with G+P+ individuals (OR 1.94; 95% CI 1.02-3.72), and G-P+ individuals (OR 2.17; 95% CI 1.39-3.39) being significantly different from the G-P- group. In conclusion, elevated iron phenotype, but not HFE genotype, was associated with shortened telomeres. Further studies will be needed to determine whether telomere length provides a marker for morbidities specifically associated with iron overload., (Copyright © 2013 Wiley Periodicals, Inc.)

Background: Many hospitalized Medical Service patients are at risk for venous thromboembolism in the months after discharge. We conducted a multicenter randomized controlled trial to test whether a hospital staff member's thromboprophylaxis alert to an Attending Physician before discharge will increase the rate of extended out-of-hospital prophylaxis and, in turn, reduce the incidence of symptomatic venous thromboembolism at 90 days., Methods: From April 2009 to January 2010, we enrolled hospitalized Medical Service patients using the point score system developed by Kucher et al to identify those at high risk for venous thromboembolism who were not ordered to receive thromboprophylaxis after discharge. There were 2513 eligible patients from 18 study sites randomized by computer in a 1:1 ratio to the alert group or the control group., Results: Patients in the alert group were more than twice as likely to receive thromboprophylaxis at discharge as controls (22.0% vs 9.7%, P <.0001). Based on an intention-to-treat analysis, symptomatic venous thromboembolism at 90 days (99.9% follow-up) occurred in 4.5% of patients in the alert group, compared with 4.0% of controls (hazard ratio 1.12; 95% confidence interval, 0.74-1.69). The rate of major bleeding at 30 days in the alert group was similar to that of the control group (1.2% vs 1.2%, hazard ratio 0.94; 95% confidence interval, 0.44-2.01)., Conclusions: Alerting providers to extend thromboprophylaxis after hospital discharge in Medical Service patients increased the rate of prophylaxis but did not decrease the rate of symptomatic venous thromboembolism., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Cysteamine, a coenzyme A metabolite, induces duodenal ulcers in rodents. Our recent studies showed that ulcer formation was aggravated by iron overload and diminished in iron deficiency. We hypothesized that cysteamine is selectively taken up in the duodenal mucosa, where iron absorption primarily occurs, and is transported by a carrier-mediated process. Here we report that cysteamine administration in rats leads to cysteamine accumulation in the proximal duodenum, where the highest concentration of iron in the gastrointestinal tract is found. In vitro, iron loading of intestinal epithelial cells (IEC-6) accelerated reactive oxygen species (ROS) production and increased [(14)C]cysteamine uptake. [(14)C]Cysteamine uptake by isolated gastrointestinal mucosal cells and by IEC-6 was pH-dependent and inhibited by unlabeled cysteamine. The uptake of [(14)C]cysteamine by IEC-6 was Na(+)-independent, saturable, inhibited by structural analogs, H(2)-histamine receptor antagonists, and organic cation transporter (OCT) inhibitors. OCT1 mRNA was markedly expressed in the rat duodenum and in IEC-6, and transfection of IEC-6 with OCT1 siRNA decreased OCT1 mRNA expression and inhibited [(14)C]cysteamine uptake. Cysteamine-induced duodenal ulcers were decreased in OCT1/2 knockout mice. These studies provide new insights into the mechanism of cysteamine absorption and demonstrate that intracellular iron plays a critical role in cysteamine uptake and in experimental duodenal ulcerogenesis., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Unlabelled: Hemochromatosis is considered by many to be an uncommon disorder, although the prevalence of HFE (High Iron) 282 Cys → Tyr (C282Y) homozygosity is relatively high in Caucasians. Liver disease is one of the most consistent findings in advanced iron overload resulting from hemochromatosis. Liver clinics are often thought to be ideal venues for diagnosis of hemochromatosis, but diagnosis rates are often low. The Hemochromatosis and Iron Overload Screening (HEIRS) Study screened 99,711 primary care participants in North America for iron overload using serum ferritin and transferrin saturation measurements and HFE genotyping. In this HEIRS substudy, serum hepatic transaminases activities (e.g., alanine aminotransferase [ALT] and aspartate aminotransferase [AST]) were compared between 162 C282Y homozygotes and 1,367 nonhomozygotes with serum ferritin levels >300 μg/L in men and >200 μg/L in women and transferrin saturation >45% in women and 50% in men. The probability of being a C282Y homozygote was determined for AST and ALT ranges. Mean ALT and AST activities were significantly lower in C282Y homozygotes than nonhomozygotes. The probability of being a C282Y homozygote increased as the ALT and AST activities decreased., Conclusion: Patients with hyperferritinemia are more likely to be C282Y homozygotes if they have normal liver transaminase activities. This paradox could explain the low yields of hemochromatosis screening reported by some liver clinics., (Copyright © 2012 American Association for the Study of Liver Diseases.)

The BMP/SMAD signalling pathway plays an important role in iron homeostasis, regulating hepcidin expression in response to body iron levels. However, the role of this pathway in the reduction in hepcidin associated with increased erythropoiesis (and secondary iron loading) is unclear. To investigate this, we established a mouse model of chronic stimulated erythropoiesis with secondary iron loading using the haemolytic agent phenylhydrazine. We then examined the expression of components of the BMP6/SMAD signalling pathway in these animals. We also examined this pathway in the Hbb(th3/+) mouse, a model of the iron loading anaemia β-thalassaemia intermedia. Increasing doses of phenylhydrazine led to a progressive increase in both liver iron levels and Bmp6 mRNA expression, but, in contrast, hepatic Hamp expression declined. The increase in Bmp6 expression was not associated with a corresponding change in the phosphorylation of hepatic SMAD1/5/8, indicating that stimulated erythropoiesis decreases the ability of BMP6 to alter SMAD phosphorylation. Increased erythropoiesis also reduces the capacity of phosphorylated SMAD (pSMAD) to induce hepcidin, as Hamp levels declined despite no changes in pSMAD1/5/8. Similar results were seen in Hbb(th3/+) mice. Thus the erythroid signal probably affects some components of BMP/SMAD signalling, but also may exert some independent effects., (© 2012 Blackwell Publishing Ltd.)

The existence of multiple inherited disorders of iron metabolism suggests genetic contributions to iron deficiency. We previously performed a genome-wide association study of iron-related single nucleotide polymorphisms (SNPs) using DNA from white men aged ≥ 25 y and women ≥ 50 y in the Hemochromatosis and Iron Overload Screening (HEIRS) Study with serum ferritin (SF) ≤ 12 µg/L (cases) and controls (SF >100 µg/L in men, SF >50 µg/L in women). We report a follow-up study of white, African-American, Hispanic, and Asian HEIRS participants, analyzed for association between SNPs and eight iron-related outcomes. Three chromosomal regions showed association across multiple populations, including SNPs in the TF and TMPRSS6 genes, and on chromosome 18q21. A novel SNP rs1421312 in TMPRSS6 was associated with serum iron in whites (p = 3.7 × 10(-6)) and replicated in African Americans (p = 0.0012).Twenty SNPs in the TF gene region were associated with total iron-binding capacity in whites (p<4.4 × 10(-5)); six SNPs replicated in other ethnicities (p<0.01). SNP rs10904850 in the CUBN gene on 10p13 was associated with serum iron in African Americans (P = 1.0 × 10(-5)). These results confirm known associations with iron measures and give unique evidence of their role in different ethnicities, suggesting origins in a common founder.

Iron overload is associated with significant morbidity and mortality yet is easily treated. The objective of this study was to create a tool that could be easily adapted to clinical practice that indicates the likelihood of a patient having undetected iron overload. We used the National Health and Nutrition Examination Survey (NHANES) 1999-2002 for US adults aged 20 years and older to build a model (unweighted n=8,779). We chose potential variables for inclusion that could be gathered by self-report or measured without laboratory data and were suggested by past literature on hemochromatosis and iron overload. We computed logistic regressions to create the scores by initially evaluating the variables' relationship with elevated ferritin and elevated transferrin saturation and then using odds ratios to correspond to scores. The resulting score on the IRon Overload ScreeNing Tool (IRON) was then validated with data on 13,844 adults in the NHANES III, 1988-94. Predictors in the final tool were age, gender, previous diagnoses of liver condition, osteoporosis or thyroid disease. The IRON score yielded an area under the curve (AUC) in the NHANES 1999-02 of 0.720 and an AUC of 0.685 in the NHANES III validation sample. The IRON score is a tool to assist in identification of patients with iron overload that has several qualities that make it attractive for use in clinical practice with an undifferentiated patient population including brevity, easily collected information and predictive ability comparable to other tools that help in directing screening., (Copyright © 2011 Wiley-Liss, Inc.)

The existence of multiple inherited disorders of iron metabolism in man, rodents and other vertebrates suggests genetic contributions to iron deficiency. To identify new genomic locations associated with iron deficiency, a genome-wide association study (GWAS) was performed using DNA collected from white men aged≥25 y and women≥50 y in the Hemochromatosis and Iron Overload Screening (HEIRS) Study with serum ferritin (SF)≤12 µg/L (cases) and iron replete controls (SF>100 µg/L in men, SF>50 µg/L in women). Regression analysis was used to examine the association between case-control status (336 cases, 343 controls) and quantitative serum iron measures and 331,060 single nucleotide polymorphism (SNP) genotypes, with replication analyses performed in a sample of 71 cases and 161 controls from a population of white male and female veterans screened at a US Veterans Affairs (VA) medical center. Five SNPs identified in the GWAS met genome-wide statistical significance for association with at least one iron measure, rs2698530 on chr. 2p14; rs3811647 on chr. 3q22, a known SNP in the transferrin (TF) gene region; rs1800562 on chr. 6p22, the C282Y mutation in the HFE gene; rs7787204 on chr. 7p21; and rs987710 on chr. 22q11 (GWAS observed P<1.51×10(-7) for all). An association between total iron binding capacity and SNP rs3811647 in the TF gene (GWAS observed P=7.0×10(-9), corrected P=0.012) was replicated within the VA samples (observed P=0.012). Associations with the C282Y mutation in the HFE gene also were replicated. The joint analysis of the HEIRS and VA samples revealed strong associations between rs2698530 on chr. 2p14 and iron status outcomes. These results confirm a previously-described TF polymorphism and implicate one potential new locus as a target for gene identification.

Unlabelled: Hereditary hemochromatosis (HH) is characterized by increased intestinal iron absorption that may result in iron overload. Although phlebotomy is widely practiced, it is poorly tolerated or contraindicated in patients with anemias, severe heart disease, or poor venous access, and compliance can vary. The once-daily, oral iron chelator, deferasirox (Exjade) may provide an alternative treatment option. Patients with HH carrying the HFE gene who were homozygous for the Cys282Tyr mutation, serum ferritin levels of 300-2000 ng/mL, transferrin saturation ≥ 45%, and no known history of cirrhosis were enrolled in this dose-escalation study to characterize the safety and efficacy of deferasirox, comprising a core and an extension phase (each 24 weeks). Forty-nine patients were enrolled and received starting deferasirox doses of 5 (n = 11), 10 (n = 15), or 15 (n = 23) mg/kg/day. Adverse events were generally dose-dependent, the most common being diarrhea, headache, and nausea (n = 18, n = 10, and n = 8 in the core and n = 1, n = 1, and n = 0 in the extension, respectively). More patients in the 15 mg/kg/day than in the 5 or 10 mg/kg/day cohorts experienced increases in alanine aminotransferase and serum creatinine levels during the 48-week treatment period; six patients had alanine aminotransferase > 3 × baseline and greater than the upper limit of normal range, and eight patients had serum creatinine > 33% above baseline and greater than upper limit of normal on two consecutive occasions. After receiving deferasirox for 48 weeks, median serum ferritin levels decreased by 63.5%, 74.8%, and 74.1% in the 5, 10, and 15 mg/kg/day cohorts, respectively. In all cohorts, median serum ferritin decreased to < 250 ng/mL., Conclusion: Deferasirox doses of 5, 10, and 15 mg/kg/day can reduce iron burden in patients with HH. Based on the safety and efficacy results, starting deferasirox at 10 mg/kg/day appears to be most appropriate for further study in this patient population.

Heritability is the proportion of observed variation in a trait among individuals in a population that is attributable to hereditary factors. The Hemochromatosis and Iron Overload Screening family study estimated heritability of serum iron measures. Probands were HFE C282Y homozygotes or non-C282Y homozygotes with elevated transferrin saturation (TS > 50%, men; TS > 45%, women) and serum ferritin concentration (SF > 300 microg/L, men; SF > 200 microg/L, women). Heritability (h(2)) was estimated by variance component analysis of TS, natural logarithm (ln) of SF, and unsaturated iron-binding capacity (UIBC). Participants (N = 942) were 77% Caucasians, 10% Asians, 8% Hispanics, and 5% other race/ethnicities. Average age (SD) was 49 (16) years; 57% were female. For HFE C282Y homozygote probands and their family members, excluding variation due to HFE C282Y and H63D genotype and measured demographic and environmental factors, the residual h(2) (SE) was 0.21 (0.07) for TS, 0.37 (0.08) for ln SF, and 0.34 (0.08) for UIBC (all P < 0.0004 for comparisons with zero). For the non-C282Y homozygote proband group, residual h(2) was significant with a value of 0.64 (0.26) for ln SF (P = 0.0096). In conclusion, serum iron measures have significant heritability components, after excluding known genetic and nongenetic sources of variation.

Background: The HEmochromatosis and IRon Overload Screening (HEIRS) Study provided data on a racially, ethnically and geographically diverse cohort of participants in North America screened from primary care populations., Methods: A total of 101,168 participants were screened by testing for HFE C282Y and H63D mutations, and measuring serum ferritin concentration and transferrin saturation. In the present review, lessons from the HEIRS Study are highlighted in the context of the principles of screening for a medical disease as previously outlined by the World Health Organization., Results: Genetic testing is well accepted, with minimal risk of discrimination. Transferrin saturation has high biological variability and relatively low sensitivity to detect HFE C282Y homozygotes, which limits its role as a screening test. Symptoms attributable to HFE C282Y homozygosity are no more common in individuals identified by population screening than in control subjects., Conclusions: Generalized population screening in a primary care population as performed in the HEIRS Study is not recommended. There may be a role for focused screening in Caucasian men, with some debate regarding genotyping followed by phenotyping, or phenotyping followed by genotyping.

An HPLC method with coulometric detection is presented for the quantitation of cysteamine, cystamine, thialysine, glutathione, glutathione disulfide and an oxidized metabolite of thialysine [S-(2-aminoethyl)-L-cysteine ketimine decarboxylated dimer (AECK-DD)]. The advantage of coulometric detection is that derivatization is unnecessary if the analyte is redox sensitive. The method was used to quantitate several sulfur-containing compounds in plasma and brain following gavage feeding of cysteamine to rats. Cysteamine, cystamine, thialysine and AECK-DD were detected in the brains of these animals. Interestingly, cysteamine treatment resulted in greatly elevated levels of cerebral methionine, despite the fact that cysteamine is not a precursor of methionine.

Cysteamine induces perforating duodenal ulcers in rats within 24-48 h. This reducing aminothiol generates hydrogen peroxide in the presence of transition metals (e.g., ferric iron), producing oxidative stress, which may contribute to organ-specific tissue damage. Since most intestinal iron absorption takes place in the proximal duodenum, we hypothesized that cysteamine may disrupt regulation of mucosal iron transport, and iron may facilitate cysteamine-induced duodenal ulceration. We show here that cysteamine-induced ulceration was aggravated by pretreatment of rats with Fe(3+) or Fe(2+) compounds, which elevated iron concentration in the duodenal mucosa. In contrast, feeding rats an iron-deficient diet was associated with a 4.6-fold decrease in ulcer formation, accompanied by a 34% decrease (P < 0.05) in the duodenal mucosal iron concentration. Administration of deferoxamine inhibited ulceration by 65%. We also observed that the antiulcer effect of H2 receptor antagonist cimetidine included a 35% decrease in iron concentration in the duodenal mucosa. Cysteamine-induced duodenal ulcers were also decreased in iron-deficient Belgrade rats (P < 0.05). In normal rats, cysteamine administration increased the iron concentration in the proximal duodenal mucosa by 33% in the preulcerogenic stage but at the same time decreased serum iron (P < 0.05). Cysteamine also enhanced activation of mucosal iron regulatory protein 1 and increased the expression of divalent metal transporter 1 mRNA and protein. Transferrin receptor 1 protein expression was also increased, although mucosal ferroportin and ferritin remained almost unchanged. These results indicate an expansion of the intracellular labile iron pool in the duodenal mucosa, increasing its susceptibility to oxidative stress, and suggest a role for iron in the pathogenesis of organ-specific tissue injury such as duodenal ulcers.

Heme carrier protein 1 (HCP1) has been identified as a possible heme carrier by in vitro analysis. To determine the association of mutations within the HCP1 gene with iron phenotypes, we examined the entire coding region of the HCP1 gene in 788 US and Canadian participants selected from the Hemochromatosis and Iron Overload Screening (HEIRS) Study using denaturing high-performance liquid chromatography. We sequenced the exon and flanking intronic regions if variants were detected. We tested 298 non-C282Y homozygotes from four racial/ethnic backgrounds (White, Black, Asian, and Hispanic) selected because they had high serum ferritin (SF) and transferrin saturations (TS). As controls, we chose 300 other random participants of the same racial/ethnic backgrounds from the same geographic locations. From the 333 HEIRS Study C282Y homozygotes, we selected 75 based on high SF and TS, 75 based on low SF and TS; and 75 were selected randomly as controls. Thirty-five of the randomly selected C282Y homozygotes were also included in the high and the low SF and TS groups due to numerical limitations. We identified eight different HCP1 genetic variants; each occurred in a heterozygous state. Except one, each was found in a single HEIRS Study participant. Thus, HCP1 variants are infrequent in the populations that we tested. Five HEIRS Study participants had non-synonymous, coding region HCP1 variants. Each of these five had TS above the 84th gender- and ethnic/racial group-specific percentile (TS percentiles: 84.7, 91.3, 97.9, 99.5, and 99.9).

Background: Previous studies have suggested a positive association of coronary heart disease risk and both serum ferritin concentrations and C282Y heterozygosity. Relationships between serum lipids, C282Y homozygosity, and serum ferritin have not been well established., Methods and Results: The Hemochromatosis and Iron Overload Screening study screened 101 168 participants in primary care from 5 field centers in the United States and Canada with serum ferritin, transferrin saturation, and HFE genotyping for C282Y and H63D mutations. Serum lipids were measured in a subset of 176 C282Y homozygotes (63 male, 113 female whites) without a prior diagnosis of, family history, or treatment for hemochromatosis and a matched sample of participants with normal transferrin saturation and serum ferritin without C282Y or H63D mutations (wild-type, 123 male, 189 female whites). The proportion of subjects who reported using prescription cholesterol-lowering medications was approximately 3 times higher in HFE wild-type subjects than C282Y homozygotes among men (22% versus 7%; P=0.02) and, in women, 2 times higher (16% versus 8%; P=0.07). After excluding subjects taking cholesterol medications, C282Y homozygotes had significantly lower mean total and low-density lipoprotein cholesterol concentrations than wild-type subjects, with larger genotypic differences for low-density lipoprotein in men (-0.62 mmol/L; 95% CI, -0.93 to -0.33) than in women (-0.28 mmol/L; 95%, CI -0.52 to -0.08)., Conclusions: Total mean serum cholesterol and low-density lipoprotein levels were lower in C282Y homozygotes than in HFE wild-type participants. Further studies are required to determine whether this is related to iron overload, HFE alleles, or other factors on C282Y-positive chromosome 6p haplotypes.

Hemochromatosis comprises a group of inherited disorders resulting from mutations of genes involved in regulating iron metabolism. The multicenter, multi-ethnic Hemochromatosis and Iron Overload Screening (HEIRS) Study screened approximately 100,000 participants in the US and Canada, testing for HFE mutations, serum ferritin and transferrin saturation. As in other studies, HFE C282Y homozygosity was common in Caucasians but rare in other ethnic groups, and there was a marked heterogeneity of disease expression in C282Y homozygotes. Nevertheless, this genotype was often associated with elevations of serum ferritin and transferrin saturation and with iron stores of more than four grams in men but not in women. If liver biopsy was performed, in some cases because of evidence of hepatic dysfunction, fibrosis or cirrhosis was often found. Combined elevations of serum ferritin and transferrin saturation were observed in non-C282Y homozygotes of all ethnic groups, most prominently Asians, but not often with iron stores of more than four grams. Future studies to discover modifier genes that affect phenotypic expression in C282Y hemochromatosis should help identify patients who are at greatest risk of developing iron overload and who may benefit from continued monitoring of iron status to detect progressive iron loading.

Background: Patients with hemochromatosis may suffer organ damage from iron overload, often with serious clinical consequences., Objective: To assess prevalences of self-reported symptoms and clinical signs and conditions in persons homozygous for the hemochromatosis gene (HFE) mutation (C282Y) identified by screening., Methods: Participants were adults 25 years of age or older enrolled in the Hemochromatosis and Iron Overload Screening (HEIRS) Study. C282Y homozygotes (n=282) were compared with control participants without the HFE C282Y or H63D alleles (ie, wild type/wild type; n=364)., Results: Previously diagnosed C282Y homozygotes and newly diagnosed homozygotes with elevated serum ferritin levels had higher prevalences of certain symptoms such as chronic fatigue (OR 2.8; 95% CI 1.34 to 5.95, and OR 2.0; 95% CI 1.07 to 3.75, respectively), and had more hyperpigmentation on physical examination (OR 4.7; 95% CI 1.50 to 15.06, and OR 3.7; 95% CI 1.10 to 12.16, respectively) and swelling or tenderness of the second and third metacarpophalangeal joints (OR 4.2; 95% CI 1.37 to 13.03, and OR 3.3; 95% CI 1.17 to 9.49, respectively) than control subjects. Joint stiffness was also more common among newly diagnosed C282Y homozygotes with elevated serum ferritin than among control subjects (OR 2.7; 95% CI 1.38 to 5.30). However, the sex- and age-adjusted prevalences of self-reported symptoms and signs of liver disease, heart disease, diabetes and most other major clinical manifestations of hemochromatosis were similar in C282Y homozygotes and control subjects., Conclusions: Some symptoms and conditions associated with hemochromatosis were more prevalent among C282Y homozygotes identified by screening than among control subjects, but prevalences of most outcomes were similar in C282Y homozygotes and controls in this primary care-based study.

Background & Aims: The aim of this study was to assess the analytic validity of self-reported family history of hemochromatosis or iron overload., Methods: A total of 141 probands, 549 family members, and 641 controls participated in the primary care Hemochromatosis and Iron Overload Screening Study. Participants received a postscreening clinical examination and completed questionnaires about personal and family histories of hemochromatosis or iron overload, arthritis, diabetes, liver disease, and heart disease. We evaluated sensitivities and specificities of proband-reported family history, and concordance of HFE genotype C282Y/C282Y in probands and siblings who reported having hemochromatosis or iron overload., Results: The sensitivities of proband-reported family history ranged from 81.4% for hemochromatosis or iron overload to 18.4% for liver disease; specificities for diabetes, liver disease, and heart disease were greater than 94%. Hemochromatosis or iron overload was associated with a positive family history across all racial/ethnic groups in the study (odds ratio, 14.53; 95% confidence intervals, 7.41-28.49; P < .0001) and among Caucasians (odds ratio, 16.98; 95% confidence intervals, 7.53-38.32; P < .0001). There was 100% concordance of HFE genotype C282Y/C282Y in 6 probands and 8 of their siblings who reported having hemochromatosis or iron overload., Conclusions: Self-reported family history of hemochromatosis or iron overload can be used to identify individuals whose risk of hemochromatosis or iron overload and associated conditions is increased. These individuals could benefit from further evaluation with iron phenotyping and HFE mutation analysis.

How often elevated serum ferritin in primary-care patients reflects increased iron stores (normally 0.8 g in men, 0.4 g in women) is not known. The Hereditary Hemochromatosis and Iron Overload Screening (HEIRS) study screened 101,168 primary-care participants (44% Caucasians, 27% African-Americans, 14% Asians/Pacific Islanders, 13% Hispanics, 2% others). Follow-up clinical evaluation was performed in 302 of 333 HFE C282Y homozygotes regardless of iron measures and 1,375 of 1,920 nonhomozygotes with serum ferritin >300 microg/L (men), >200 microg/L (women) and transferrin saturation >50% (men), >45% (women). Quantitative phlebotomy was conducted in 122 of 175 C282Y homozygotes and 122 of 1,102 nonhomozygotes with non-transfusional serum ferritin elevation at evaluation. The estimated prevalence in the Caucasian population of C282Y homozygotes with serum ferritin >900 microg/L at evaluation was 20 per 10,000 men and 4 per 10,000 women; this constellation was predictive of iron stores >4 g in men and >2 g in women. The estimated prevalence per 10,000 of non-C282Y homozygotes with serum ferritin >900 microg/L at evaluation was 7 among Caucasians, 13 among Hispanics, 20 among African Americans, and 38 among Asians and Pacific Islanders, and this constellation was predictive of iron stores >2 g but <4 g. In conclusion, serum ferritin >900 microg/L after initial elevations of both serum ferritin and transferrin saturation is predictive of mildly increased iron stores in multiple ethnic populations regardless of HFE genotype. Serum ferritin >900 microg/L in male C282Y homozygotes is predictive of moderately increased iron stores., (Copyright 2008 Wiley-Liss, Inc.)

There are few descriptions of young adults with self-reported hemochromatosis or iron overload (H/IO). We analyzed initial screening data in 7,343 HEmochromatosis and IRon Overload Screening (HEIRS) Study participants ages 25-29 years, including race/ethnicity and health information; transferrin saturation (TS) and ferritin (SF) measurements; and HFE C282Y and H63D genotypes. We used denaturing high-pressure liquid chromatography and sequencing to detect mutations in HJV, TFR2, HAMP, SLC40A1, and FTL. Fifty-one participants reported previous H/IO; 23 (45%) reported medical conditions associated with H/IO. Prevalences of reports of arthritis, diabetes, liver disease or liver cancer, heart failure, fertility problems or impotence, and blood relatives with H/IO were significantly greater in participants with previous H/IO reports than in those without. Only 7.8% of the 51 participants with previous H/IO reports had elevated TS; 13.7% had elevated SF. Only one participant had C282Y homozygosity. Three participants aged 25-29 years were heterozygous for potentially deleterious mutations in HFE2, TFR2, and HAMP promoter, respectively. Prevalences of self-reported conditions, screening iron phenotypes, and C282Y homozygosity were similar in 1,165 participants aged 30 years or greater who reported previous H/IO. We conclude that persons who report previous H/IO diagnoses in screening programs are unlikely to have H/IO phenotypes or genotypes. Previous H/IO reports in some participants could be explained by treatment that induced iron depletion before initial screening, misdiagnosis, or participant misunderstanding of their physician or the initial screening questionnaire.

Background: Transferrin saturation is widely considered the preferred screening test for hemochromatosis. Unsaturated iron-binding capacity has similar performance at lower cost. However, the within-person biological variability of both these tests may limit their ability at commonly used cut points to detect HFE C282Y homozygous patients., Methods: The Hemochromatosis and Iron Overload Screening Study screened 101,168 primary care participants for iron overload using transferrin saturation, unsaturated iron-binding capacity, ferritin, and HFE C282Y and H63D genotyping. Transferrin saturation and unsaturated iron-binding capacity were performed at initial screening and again when selected participants and controls returned for a clinical examination several months later. A missed case was defined as a C282Y homozygote who had transferrin saturation below the cut point (45% for women, 50% for men) or unsaturated iron-binding capacity above the cut point (150 micromol/L for women, 125 micromol/L for men) at the initial screening or the clinical examination, or both, regardless of serum ferritin., Results: There were 209 C282Y previously undiagnosed homozygotes with transferrin saturation and unsaturated iron-binding capacity testing performed at the initial screening and clinical examination. Sixty-eight C282Y homozygotes (33%) would have been missed at these transferrin saturation cut points (19 men, 49 women; median serum ferritin level of 170 microg/L; first and third quartiles, 50 and 474 microg/L), and 58 homozygotes (28%) would have been missed at the unsaturated iron-binding capacity cut points (20 men, 38 women; median serum ferritin level of 168 microg/L; first and third quartiles, 38 and 454 microg/L). There was no advantage to using fasting samples., Conclusions: The within-person biological variability of transferrin saturation and unsaturated iron-binding capacity limits their usefulness as an initial screening test for expressing C282Y homozygotes.

We characterized HFE C282Y homozygotes aged 25-29 years in the HEmochromatosis and IRon Overload Screening (HEIRS) Study using health questionnaire responses, transferrin saturation (TfSat), serum ferritin (SF), and HFE genotyping. In eight homozygotes, we used denaturing high-performance liquid chromatography and sequencing to search for HFE2 (= HJV), TFR2, HAMP, SLC40A1 (= FPN1), and FTL mutations. Sixteen of 4,008 White or Hispanic participants aged 25-29 years had C282Y homozygosity (15 White, 1 Hispanic); 15 were previously undiagnosed. Eleven had elevated TfSat; nine had elevated SF. None reported iron overload-associated abnormalities. No deleterious non-HFE mutations were detected. The prevalence of C282Y homozygosity in White or Hispanic HEIRS Study participants aged 25-29 years did not differ significantly from the prevalence of C282Y homozygosity in older White or Hispanic HEIRS Study participants. The prevalences of reports of iron overload-associated abnormalities were not significantly different in these 16 C282Y homozygotes and in HFE wt/wt control participants aged 25-29 years who did not report having hemochromatosis or iron overload. We conclude that C282Y homozygotes aged 25-29 years diagnosed by screening infrequently report having iron overload-associated abnormalities, although some have elevated SF. Screening using an elevated TfSat criterion would fail to detect some C282Y homozygotes aged 25-29 years.

Purpose: We sought to determine the prevalence of elevated measures of iron status in African Americans and whether the combination of serum ferritin concentration >200 microg/L for women or >300 microg/L for men and transferrin saturation in the highest quartile represents increased likelihood of mutation of HFE, self-reported iron overload or self-reported liver disease., Subjects and Methods: A cross-sectional observational study of 27,224 African Americans > or =25 years of age recruited in a primary care setting was conducted as part of the multi-center, multi-ethnic Hemochromatosis and Iron Overload Screening (HEIRS) Study. Measurements included serum ferritin concentration, transferrin saturation, testing for HFE C282Y and H63D, and self-reported iron overload and liver disease., Results: Serum ferritin concentration >200 microg/L for women or >300 microg/L for men occurred in 5263 (19.3%) of African Americans, while serum ferritin concentration in this range with highest-quartile transferrin saturation (>29% women; >35% men) occurred in 1837 (6.7%). Adjusted odds of HFE mutation (1.76 women, 1.67 men), self-reported iron overload (1.97 women, 2.88 men), or self-reported liver disease (5.18 women, 3.73 men) were greater with elevated serum ferritin concentration and highest-quartile transferrin saturation than with nonelevated serum ferritin concentration (each P <.05)., Conclusions: Serum ferritin concentration >200 microg/L for women or >300 microg/L for men in combination with transferrin saturation >29% for women or >35% for men occurs in approximately 7% of adult African American primary care patients. Patients with this combination of iron test results should be evaluated for increased body iron stores or liver disease.

Iron overload phenotypes in persons with and without hemochromatosis are variable. To investigate this further, probands with hemochromatosis or evidence of elevated iron stores and their family members were recruited for a genome-wide linkage scan to identify potential quantitative trait loci (QTL) that contribute to variation in transferrin saturation (TS), unsaturated iron-binding capacity (UIBC), and serum ferritin (SF). Genotyping utilized 402 microsatellite markers with average spacing of 9 cM. A total of 943 individuals, 64% Caucasian, were evaluated from 174 families. After adjusting for age, gender, and race/ethnicity, there was evidence for linkage of UIBC to chromosome 4q logarithm of the odds (LOD) = 2.08, p = 0.001) and of UIBC (LOD = 9.52), TS (LOD = 4.78), and SF (LOD = 2.75) to the chromosome 6p region containing HFE (each p < 0.0001). After adjustments for HFE genotype and other covariates, there was evidence of linkage of SF to chromosome 16p (LOD = 2.63, p = 0.0007) and of UIBC to chromosome 5q (LOD = 2.12, p = 0.002) and to chromosome 17q (LOD = 2.19, p = 0.002). We conclude that these regions should be considered for fine mapping studies to identify QTL that contribute to variation in SF and UIBC.

The ferroportin (FPN1) Q248H polymorphism has been associated with increased serum ferritin (SF) levels in sub-Saharan Africans and in African Americans (AA). AA participants of the HEIRS Study who did not have HFE C282Y or H63D who had elevated initial screening SF (> or =300 microg/L in men and >= or =200 microg/L in women) (defined as cases) were frequency-matched to AA participants with normal SF (defined as controls) to investigate the association of the Q248H with elevated SF. 10.4% of cases and 6.7% of controls were Q248H heterozygotes (P=0.257). Q248H homozygosity was observed in 0.5% of the cases and none of the controls. The frequency of Q248H was higher among men with elevated SF than among control men (P=0.047); corresponding differences were not observed among women. This appeared to be unrelated to self-reports of a previous diagnosis of liver disease. Men with elevated SF were three times more likely than women with elevated SF to have Q248H (P=0.012). There were no significant differences in Q248H frequencies in men and women control participants. We conclude that the frequency of the FPN1 Q248H polymorphism is greater in AA men with elevated SF than in those with normal SF.

Background: Asians and Pacific Islanders in the Hemochromatosis and Iron Overload Screening (HEIRS) Study had the highest prevalence of elevated serum ferritin (SF) and transferrin saturation (TS) levels, but to our knowledge, the reasons for this have not been investigated., Methods: Using multiple linear regression, we compared TS and SF distributions for 42 720 Asian, Pacific Islander, and white HEIRS Study participants recruited through 5 field centers in North America who did not have HFE C282Y or H63D alleles., Results: Compared with their white counterparts, Asian men had a 69-ng/mL (155-pmol/L) higher adjusted mean SF level and a 3% higher TS level (P<.001); Asian women had 23-ng/mL (52-pmol/L) higher adjusted mean SF level and a 3% higher TS level (P<.001). The mean TS level of Asian women was higher than that of Pacific Islander women, and the mean SF level of Pacific Islander men was significantly higher than that of white men. These differences remained significant after adjusting for self-reported history of diabetes or liver disease. Additional information for selected participants suggested that these differences are largely unrelated to mean corpuscular volume less than 80 fL, body mass index, or self-reported alcohol intake. Available liver biopsy and phlebotomy data indicated that iron overload is probably uncommon in Asian participants., Conclusion: Higher TS and SF levels in persons of Asian or Pacific Island heritage may need to be interpreted differently than for whites, although the biological basis and clinical significance of higher levels among Asians and Pacific Islanders are unclear.