Acton, Ronald T.

Abstract Mutations in the hemojuvelin gene (HJV) are a cause of juvenile hemochromatosis (JH), but do they influence the phenotype of patients with adult-onset hemochromatosis with or without mutations of the HFE gene? We sequenced the coding region of the HJV gene of 133 subjects with primary iron overload (75 whites: 50 HFE, 25 non-HFE associated; 51 blacks: 1 HFE-associated; 7 Asians). A 63 year old white woman with non-HFE iron overload was found to be a compound heterozygote for HJV mutations: one previously identified (G320V); the other novel (C321W). The patient was diagnosed at age 30 (SI 223 μg/100 mL, TIBC 293 μg/100 mL, TS 76%, hepatic iron 31,154 μg/g, hepatic iron index 19.2). She had 2 healthy children, developed amenorrhea at age 23, had a history of hypothyroidism and developed Type 2 diabetes at age 59. She was iron depleted after 66 phlebotomies. Among 74 other white subjects with iron overload we found 3 polymorphisms: IVS2-6 C>G (3 subjects); nt 165 T>A (G55G), and IVS4-50 C>T (1 subject, each). Among 51 black iron overloaded and 132 black control subjects, the most notable polymorphism was a DNA triplet insert predicting an insertion of glycine. This was found in 2 subjects, one with and one without iron storage disease. Among the iron overloaded black subjects, we also found IVS2-6 C>G (1 subject), nt -140 G>C (3 subjects), nt 792 G>C (S264S) (1 subject), nt 828 C>A (I275I) (1 subject), and nt 929 C>G (A310G) (2 subjects). These polymorphisms, excluding S264S and I275I, were found in control subjects as well. No coding region mutations or polymorphisms were found in the 7 Asian iron overloaded subjects. We also determined the gene frequency of the HJV I222N and G320V mutations in adult control subjects from central Alabama, where a JH index case had been found with these mutations. Allele frequencies of I222N and G320V were 0.002 (n=240) and 0 (n=241) respectively in control whites. A white control female heterozygous for the I222N was also heterozygous for HFE C282Y but had normal iron measures. No I222N and G320V mutations were found in 124 and 118 black subjects respectively. We conclude that: 1) iron overloaded patients without HFE mutations, with or without a JH phenotype should be screened for HJV; 2) HJV mutations do not account for most cases of increased penetrance of HFE-associated hemochromatosis; 3) double heterozygosity for HFE C282Y and HJV I222N does not necessarily cause iron overload.

Abstract Abstract 2105 The existence of multiple inherited disorders of iron metabolism in man, rodents and other vertebrates suggests genetic contributions to iron deficiency. We hypothesized that common variants in genes involved in iron metabolism may modulate susceptibility or resistance to the development of iron deficiency in humans. To examine the association between single nucleotide polymorphisms (SNPs) in key genes involved in iron metabolism pathways, we previously performed a genome-wide association study 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 controls (SF >100 μg/L in men, SF >50 μg/L in women). We now report on a multiethnic follow-up association study of HEIRS participants. Candidate SNPs were identified from our GWAS and the scientific literature. Population samples of whites, African Americans, Hispanics, and Asians from the U.S. and Canada were analyzed separately for association between SNPs and case-control status and each of seven quantitative outcomes including serum iron, total iron-binding capacity (TIBC), unsaturated iron-binding capacity (UIBC), transferrin saturation, SF, serum transferrin receptor, and body iron. There were 1084 white (357 cases, 727 controls), 153 Asian (51 cases, 102 controls), 221 African American (77 cases, 144 controls) and 233 of 239 Hispanic individuals (79 cases, 160 controls) that passed quality control. For the African-American and Hispanic samples, ancestry proportions were estimated based on genotypes of ancestry informative markers. Regression analysis was used to examine the association between case-control status and quantitative serum iron measures and 1134, 1115, 1113 and 1134 SNP genotypes in the white, African-American, Hispanic, and Asian population samples, respectively. Model predictors included age, sex, the estimated ancestry proportion (for African American and Hispanic only), genotype, and measured covariates that showed nominally significant associations with the outcome. Three chromosomal regions showed evidence of association across multiple populations, including SNPs in the TF gene on chromosome 3q22, the TMPRSS6 gene on chromosome 22q12, and loci on chromosome 18q21. SNP rs1421312 in TMPRSS6 was associated with serum iron in whites (p=4.7×10−7) and was replicated in African Americans (p=0.0012).Twenty SNPs in the TF gene region were significantly associated with TIBC in the white sample (p<4.4×10−5); six SNPs were replicated in other ethnicities (p< 0.01). SNP rs10904850 in the CUBN gene on 10p13 was significantly associated with serum iron in the African-American sample (P=1.0×10−5). Mutations in the TMPRSS6 gene have been implicated in iron-refractory iron deficiency anemia through linkage studies. We found a novel SNP in TMPRSS6 that was associated with serum iron in whites and replicated in African Americans, suggesting a role for this SNP in increasing the risk of iron deficiency in affected persons. Our results confirm known associations with iron measures and give evidence of their role in different ethnic groups, a unique aspect of this study, suggesting origins in a common founder. Disclosures: No relevant conflicts of interest to declare.

Abstract It is well-recognized that Helicobacter pylori infection causes gastrointestinal blood loss and iron deficiency. H. pylori gastritis has also been implicated in iron deficiency refractory to oral iron replacement therapy. Although H. pylori infection is common in multiple populations, less is known about the extent to which H. pylori contributes to iron deficiency in different racial/ethnic groups. To address this question, we tested the serum collected from men aged ≥ 25 y and women ≥ 50 y in the Hemochromatosis and Iron Overload Screening (HEIRS) Study to identify those with iron deficiency (defined as serum ferritin ≤ 12 mg/L [cases]) and iron-replete controls (serum ferritin > 100 mg/L in men, serum ferritin > 50 mg/L in women). All samples were tested for H. pylori IgG antibodies and for antibodies to CagA (cytotoxin-associated gene-bearing strain). We tested 571 cases and 1142 controls. Participants were considered to have evidence of H. pylori infection if they had positive results for both antibodies or for either antibody alone. Participants who did not have a result for either test were excluded. We examined the association between the presence of H. pylori in cases and controls among Caucasians, Asian/Pacific Islanders, African Americans, and Hispanics. Among Caucasians, evidence of H. pylori infection was comparable in cases and controls; 170 of 735 controls (23.1%) and 97 of 363 cases (26.7%), respectively, were positive. Similar results were found in African Americans (56.3% of 144 controls; 55.8% of 77 cases) and Hispanics (66.7% of 159 controls; 59.5% of 79 cases). However, in Asian/Pacific Islanders, the prevalence of H. pylori was higher among cases (62.8% of 51) than controls (44.1% of 102), p=0.029 by the likelihood ratio Chi-Square test. The relative risk (RR) of iron deficiency among those with H. pylori-positivity was significantly greater than in those without (RR, 1.66; 95% CI [1.04, 2.66]). A comparison of subgroups by positivity for IgG or CagA showed that the relative risk of iron deficiency was increased among those with IgG positivity, with or without Cag A positivity (RR, 1.80 and 1.90, respectively), but not among those with CagA positivity alone (RR, 1.00). H. pylori infection is a frequent contributor to iron deficiency but is also common in the general population. Our results indicate that among HEIRS Study Asian/Pacific Islander participants, H. pylori infection is more prevalent in cases with iron deficiency than in controls. In contrast, there was no difference in the prevalence of H. pylori infection between cases and controls among Caucasians, African Americans, and Hispanics. These results have implications for the investigation of iron deficiency in Asians and Pacific Islanders. Disclosures No relevant conflicts of interest to declare.

Abstract Abstract 2095 Celiac disease (CD) is an increasingly recognized disorder in Caucasian populations of European origin. Little is known about its prevalence in non-Caucasians. While CD is thought to be a cause of iron deficiency anemia, the extent to which CD contributes to iron deficiency in Caucasians and especially non-Caucasians is unknown. Iron deficiency is one of the most common nutritional deficiencies in both the developed world and in developing countries. Thus, it is important to know the prevalence of CD in different populations and in iron-deficient and iron-replete persons. To answer these questions, we tested serum collected from Caucasian and non-Caucasian men aged ≥ 25 y and women ≥ 50 y in the Hemochromatosis and Iron Overload Screening (HEIRS) Study. In the HEIRS Study, 101,168 participants were screened with serum biochemical tests of iron status, which not only detected participants with iron overload but also identified a unique multiethnic population of participants with iron deficiency. We hypothesized that CD is more common in those with iron deficiency than in iron-replete individuals. We also examined the difference in frequency of CD between Caucasians and non-Caucasians with iron deficiency. Cases with iron deficiency (defined as serum ferritin ≤ 12 μg/L [cases]) and iron-replete controls (serum ferritin > 100 μg/L in men, serum ferritin > 50 μg/L in women) were further evaluated by using a sequential serological testing scheme whereby all samples were tested with an ELISA for human recombinant tissue transglutaminase IgA antibodies, and positive values were confirmed by endomysial antibodies. Those positive for both tests were considered double positives and were presumed to have untreated CD. Those positive for tissue transglutaminase IgA antibodies but not for endomysial antibodies were termed single positives and were considered indeterminate and excluded from analysis. We further hypothesized that low serum ferritin and an appropriate human leukocyte antigen (HLA) variant, may be predictive of CD. We used SNP-based analysis to determine HLA genotype and DQ8, DQ2.2 or DQ4, and DQ2.5 risk variants. Fisher's exact test was used to examine the association between iron−deficient case and control status and the presence of celiac disease. Log-binomial regression was applied to estimate the odds of celiac disease in iron-deficient cases relative to that of controls. A total of 1713 subjects were tested for tissue transglutaminase IgA antibodies. Participants included 1100 Caucasians, 221 African Americans, 153 Asians, and 239 Hispanics. Fourteen of 571 iron-deficient cases were positive for the double serology compared to just one of 1142 controls. All of the seropositive tests were seen in Caucasians and none in the non-Caucasians. Excluding data from participants with indeterminate serological screen results (6 Caucasians, 4 non-Caucasians), we found that CD occurred in 14 of 567 cases (2.5%) and in only 1 of 1136 (0.1%) controls (Fisher's exact test, p=1.92 10−6). CD was more common in Caucasian cases (14 of 363, 4%) than in non-Caucasian cases (0 of 204, p=0.003). Only one Caucasian control and none of the non-Caucasian controls had CD. The odds of CD in individuals with iron deficiency was 28 (3.7, 212.8) times that in controls. Thirteen of 14 iron-deficient cases with CD carried the DQ2.5 variant of the HLA genotype. Presence of DQ2.5 was highly significantly associated with celiac disease status in iron-deficient cases compared to controls (Fisher's exact test, p = 7.183 × 10−8). The results indicate that CD is a small but significant contributor to iron deficiency in Caucasians. CD is very rare in other races, even among individuals with features frequently seen in CD, such as iron deficiency. CD is also rare in Caucasians who are iron replete. CD testing should be considered for adult Caucasian males or post-menopausal females having iron deficiency without evidence of other etiologies such as gastrointestinal blood loss. Patients identified with CD may benefit from appropriate treatment. Disclosures: No relevant conflicts of interest to declare.

AbstractThese cancer genetic counseling recommendations describe the medical, psychosocial, and ethical ramifications of identifying at‐risk individuals through cancer risk assessment with or without genetic testing. They were developed by members of the Practice Issues Subcommittee of the National Society of Genetic Counselors Cancer Genetic Counseling Special Interest Group. The information contained in this document is derived from extensivereview of the current literature on cancer genetic risk assessment and counseling as well as the personal expertise of genetic counselors specializing in cancer genetics. The recommendations are intended to provid information about the process of genetic counseling and risk assessment for hereditary cancer disorders rather than specific information about individual syndromes. Key components include the intake (medical and family histories), psychosocial assessment (assessment of risk perception), cancer risk assessment (determination and communication of risk), molecular testing for hereditary cancer syndromes (regulations, informed consent, and counseling process), and follow‐up considerations. These recommendations should not be construed as dictating an exclusive course of management, nor does use of such recommendations guarantee a particular outcome. These recommendations do not displace a health care provider's professional judgment based on the clinical circumstances of a client.