Assessment of iron overload in a cohort of Sri Lankan patients with transfusion dependent beta thalassaemia and its correlation with pathogenic variants in HBB, HFE, SLC40A1, and TFR2 genes.

BACKGROUND: Iron overload (IO) is a complication in transfusion dependent beta thalassaemia (TDT). Pathogenic variants in genes involving iron metabolism may confer increased risk of IO. The objective of this study was to determine the magnitude of the cardiac and hepatic IO and determine whether pathogenic variants in HFE, SLC40A1 and TFR2 genes increase the risk of IO in a cohort of TDT patients in Sri Lanka. MATERIALS AND METHODS: Fifty-seven (57) patients with TDT were recruited for this study. Serum ferritin was done once in 3 months for a period of one year in all. Those who were ≥ 8 years of age (40 patients) underwent T2* MRI of the liver and heart. Fifty-two (52) patients underwent next generation sequencing (NGS) to identify pathogenic variants in HBB, HFE, SLC40A1 and TFR2 genes. RESULTS: The median age of the patients of this cohort was 10 years. It comprised of 30 (52.6%) boys and 27 (47.4%) girls. The median level of serum ferritin was 2452 ng/dl. Hepatic IO was seen in 37 (92.5%) patients and cardiac IO was seen in 17 (42.5%) patients. There was no statistically significant correlation between serum ferritin and hepatic or cardiac IO. Thirty-two (61.5%), 18 (34.6%), 2 (3.8%) of patients were homozygotes, compound heterozygotes and heterozygotes for pathogenic variants in the HBB gene. Eight (15.4%) and 1 (1.9%) patients were heterozygotes for pathogenic and likely pathogenic variants of HFE genes respectively. There were no pathogenic variants for the TfR2 and SLC40A1 genes. The heterozygotes of the pathogenic variants of the HFE were not at increased risk of IO. CONCLUSIONS: Cardiac T2* MRI helps to detect cardiac IO in asymptomatic patients. It is important to perform hepatic and cardiac T2* MRI to detect IO in patients with TDT. There was no statistically significant correlation between pathogenic variants of HBB and HFE genes with hepatic and cardiac IO in this cohort of patients.

Erythrocytapheresis versus phlebotomy in the initial treatment of HFE hemochromatosis patients: results from a randomized trial.

BACKGROUND: Standard treatment of newly diagnosed HFE hemochromatosis patients is phlebotomy. Erythrocytapheresis provides a new therapeutic modality that can remove up to three times more red blood cells per single procedure and could thus have a clinical and economic benefit. STUDY DESIGN AND METHODS: To compare the number of treatment procedures between erythrocytapheresis and phlebotomy needed to reach the serum ferritin (SF) target level of 50 µg/L, a two-treatment-arms, randomized trial was conducted in which 38 newly diagnosed patients homozygous for C282Y were randomly assigned in a 1:1 ratio to undergo either erythrocytapheresis or phlebotomy. A 50% decrease in the number of treatment procedures for erythrocytapheresis compared to phlebotomy was chosen as the relevant difference to detect. RESULTS: Univariate analysis showed a significantly lower mean number of treatment procedures in the erythrocytapheresis group (9 vs. 27; ratio, 0.33; 95% confidence interval [CI], 0.25-0.45; Mann-Whitney p < 0.001). After adjustments for the two important influential factors initial SF level and body weight, the reduction ratio was still significant (0.43; 95% CI, 0.35-0.52; p < 0.001). Cost analysis showed no significant difference in treatment costs between both procedures. The costs resulting from productivity loss were significantly lower for the erythrocytapheresis group. CONCLUSION: Erythrocytapheresis is highly effective treatment to reduce iron overload and from a societal perspective might potentially also be a cost-saving therapy.

A decision analysis model for diagnostic strategies using DNA testing for hereditary haemochromatosis in at risk populations.

BACKGROUND: New techniques for diagnosing hereditary haemochromatosis (HHC) have become available alongside traditional tests such as liver biopsy and serum iron studies. AIM: To evaluate DNA tests in people suspected of having haemochromatosis at clinical presentation compared to liver biopsy, and in family members of those diagnosed with haemochromatosis compared to phenotypic iron studies in UK. METHODS: Decision analytic models were constructed to compare the costs and consequences of the diagnostic strategies for a hypothetical cohort of people with suspected haemochromatosis. For each strategy, the number of cases of haemochromatosis identified and treated and the resources used were estimated. RESULTS: For diagnostic strategies in people suspected clinically of having haemochromatosis, the DNA strategy is cost saving compared to liver biopsy (cost saved per case detected, 123 pounds) and continues to be so across all ranges of parameters. For family testing, the DNA strategy is cost saving for the offspring of the proband but not for siblings. If the DNA test cost were to reduce by 40% to 60 pounds or, if in the phenotypic model, those with initially normal iron indices were retested twice instead of once, the DNA strategy would be the cheaper one. CONCLUSION: Diagnostic strategies involving DNA testing are likely to be cost saving in clinical cases with iron overload and in the offspring of index cases. This study supports the UK guideline recommendations for the use of DNA testing in UK.

Recent advances in the pathophysiology, diagnosis and treatment of hereditary hemochromatosis and other iron overload syndromes.

Recent years have witnessed tremendous advances in the fields of pathophysiology, diagnosis and management of hereditary hemochromatosis (HH) and other iron overload syndromes, the dreadful consequences of which are fully preventable by early diagnosis and treatment. Missense mutations in HFE, a newly discovered gene encoding for a major histocompatibility class-I like molecule, have been found to be strictly associated with most cases of HH. The mechanisms by which a dysfunctional HFE molecule determines increased absorption of iron in HH are on the way to be fully clarified, due to the availability of a knockout mouse model. Epidemiologic studies have shown that HH is one of the most common human hereditary disorders. The possibility to identify HFE heterozygotes by means of a simple genetic test have prompted studies on the association between HFE mutations and iron overload syndromes different from HH. In the era of the historic completion of the human genome projects, genetic testing for HH may soon qualify for being adopted in universal population screening policies. In the present paper, the recent advances in the fields of genetics and pathophysiology of HH and other iron overload syndromes will be summarized. Furthermore, its clinical features, pathology and treatment will be reviewed, and the emerging issues of cost-effective diagnosis and of possible population screening strategies will be succintly discussed.

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.

Semiquantitative and qualitative assessment of hepatic iron in patients with chronic viral hepatitis: relation with grading, staging and haemochromatosis mutations.

BACKGROUND: Hepatic iron overload is a common but still poorly characterized finding in patients with chronic viral hepatitis. AIM: To evaluate lobular and cellular distribution of iron in patients with chronic viral hepatitis, the relation between hepatic iron distribution, grading and staging, and the frequency of haemochromatosis gene mutations. PATIENTS: Thirty-four patients with chronic viral hepatitis and iron overload; 34 matched chronic viral hepatitis controls without iron overload; 139 healthy controls. METHODS: Hepatic iron was assessed by hepatic iron concentration and Deugnier's score, histological grading and staging by Ishak's score, and frequency of haemochromatosis gene mutations by polymerase chain reaction-restriction assays. RESULTS AND CONCLUSIONS: Iron deposits were found in hepatocytes (94% of the patients), sinusoidal tracts (88%) and portal cells (59%). In 41%, iron deposits were homogeneously distributed in the hepatic specimen. Hepatocytic iron showed a decreasing gradient from Rappaport's zone 1 to 3. Heavy alcohol intake influenced the distribution rather than the amount of hepatic iron by increasing sinusoidal iron. Haemochromatosis gene mutations were more frequent in chronic viral hepatitis patients with iron overload than in those without iron overload and in healthy controls suggesting they contribute to pathogenesis of hepatic iron accumulation. The correlation between hepatic fibrosis and portal iron supports the fibrogenetic role of iron in chronic viral hepatitis.

Population-based screening for hemochromatosis using phenotypic and DNA testing among employees of health maintenance organizations in Springfield, Missouri.

BACKGROUND: Hemochromatosis reportedly affects 3 to 8 persons per 1,000 and is associated with an elevated risk of morbidity and mortality. We sought to ascertain its prevalence in a community and to assess the association between phenotype and genotype. METHODS: All health maintenance organization employees were invited to participate in hemochromatosis screening using a repeated elevation of the transferrin saturation test as the case definition (> or = 50% in women and > or = 60% in men with no other cause). Iron overload from hemochromatosis was defined as serum ferritin concentration > or = 95th percentile and mobilizable iron > or = 99th percentile for age and sex, or hepatic iron index > or = 1.9. The HFE gene was analyzed for mutations. RESULTS: Participation among employees was 28% (1,653 of 6,000); 83% were women. The prevalence of hemochromatosis was 8 per 1,000 (13 of 1,653), and the prevalence of iron overload from hemochromatosis was 4 per 1,000 (5 of 1,653). Compared with those who had no HFE mutation, the relative risk (RR) for hemochromatosis was greatest for C282Y homozygotes (RR = 147), compound heterozygotes (RR = 19), and H63D homozygotes (RR = 9). Overall, 38% of participants had at least one HFE mutation. Screening based on an initial elevated transferrin saturation test had the best sensitivity, whereas DNA testing offered the best specificity and predictive value positive for iron overload disease. CONCLUSIONS: In this population, we found a greater than expected prevalence of hemochromatosis and demonstrated a clear association with the HFE genotype. Promotion of screening is complicated by controversies in case definition and the large number of persons who will be detected before they have clinically significant iron loading, in whom the risk of clinical disease is unknown. Larger screening studies in more diverse populations are necessary to characterize the burden of disease and to follow those at risk (based on HFE or iron status measures) to establish the natural history of hemochromatosis.