Status of HFE mutation in thalassemia syndromes in north India

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.

Impact of HFE-2 and HAMP Gene Variations on Iron Overload in Pediatric Patients with Non-Transfusion Dependent Thalassemia: A Pilot Study

Patients with non-transfusion dependent thalassemia (NTDT) develop variable degrees of iron overload. Possible genes which may be implicated in causing iron overload are hepcidin (HAMP) and hemojuvelin (HFE). There is variable data assessing the role of c.-582Y A > G HAMP gene and H63D hotspot in HFE-1 gene in causing iron overload, while role of HFE-2 gene is undetermined. Twenty-five patients with NTDT (≥ 10 years) were assessed for iron overload. Genetic analysis for β-globin, α-globin, HAMP, HFE-2 and C282Y and H63D hotspots in HFE-1 genes was performed. T2*MRI demonstrated elevated LIC in 48% patients. No mutations were detected in HAMP gene or HFE-1 hotspots. Four single nucleotide variations (SNV) were detected in HFE-2 gene in 4 (20%) patients, including a novel SNV, p.Gln315Arg in 2 patients in heterozygous state. This is a likely pathogenic mutation; however, in heterozygous state, it did not lead to iron overload. HAMP and HFE-2 gene variations were infrequently seen in this pilot study, with no significant impact on iron overload. Presence of SNV p.Gln315Argin HFE-2 gene needs to be evaluated in larger sample sizes in our population to determine the incidence in homozygous state and its association with iron overload.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s12288-021-01442-9.

Frequency of hereditary hemochromatosis gene mutations and their effects on iron overload among beta thalassemia patients of Chennai residents

<abstract> <p>Hereditary Hemochromatosis (HH) is an autosomal recessive disorder of iron metabolism associated with <italic>HFE</italic> gene mutations, characterized by increased iron absorption and accumulation leading to multi-organ damage caused by iron overload toxicity. Beta thalassemia is caused by a mutation in the human beta globin gene. Imbalanced production of globin chain results in beta thalassemia, where the unpaired alpha chains precipitates in red cell precursors leading to ineffective erythropoiesis and reduced RBC survival. Both HH and beta thalassemia condition results in rapid accumulation of iron lead to iron overload in tissues and organs. The study aims to analyze the frequency of <italic>HFE</italic> variants among beta thalassemia cases and their effect on iron overload. The frequency of three <italic>HFE</italic> variants C282Y, H63D, S65C was analyzed by PCR RFLP method among Beta Thalassemia Trait (BTT) (n = 203), Beta Thalassemia Major (BTM) (n = 19) and age and sex-matched control samples (n = 200). The present study furnished allele frequency of H63D variant in BTT, BTM and controls 8.13, 15.8 and 6% respectively. Ten out of 33 heterozygous H63D variants exhibited iron overload with higher ferritin levels indicating <italic>HFE</italic> variant might aggravate the absorption of iron. The C282Y variant was present in heterozygous state in 1 case among beta thalassemia carriers. The C282Y variant was absent among BTM and control cases. S65C <italic>HFE</italic> variant was absent in the present study. Iron overload was completely absent in the control cases among all three <italic>HFE</italic> genotypes. Hence it is inferred from the present investigation, analysis of <italic>HFE</italic> genes and iron status will remarkably help to reason out the probable reason behind the iron status and support in proper management of beta thalassemia cases.</p> </abstract>

Late-onset Hemochromatosis: Co-inheritance of β-thalassemia and Hereditary Hemochromatosis in a Chinese Family: A Case Report and Epidemiological Analysis of Diverse Populations

Hereditary hemochromatosis and β-thalassemia can both result in the inappropriately low production of the hormone hepcidin, which leads to an increase in intestinal absorption and excessive iron deposition in the parenchymal cells. To the best of our knowledge, there have been no reports on the coexistence of the two disorders in China. We herein report a case in a Chinese who presented with late-onset hepatic cirrhosis with hereditary hemochromatosis and β-thalassemia. We analyzed the pedigree of the two disorders and the iron status in his family members. Our case supports that a heterozygous H63D mutation can interact with β-thalassemia, leading to late-onset hemochromatosis.

The Correlation of Cardiac and Hepatic Hemosiderosis as Measured by T2*MRI Technique with Ferritin Levels and Hemochromatosis Gene Mutations in Iranian Patients with Beta Thalassemia Major

Objectives

Organ-specific hemosiderosis and iron overload complications are more serious and more frequent in some patients with beta thalassemia major (BTM) compared with others. We investigated whether coinheritance of HFE H63D or C282Y gene mutations in patients with BTM contributes to the phenotypic variation of iron overload complications and assessed the correlation of cardiac and hepatic hemosiderosis with plasma ferritin levels.

Methods

We studied 60 patients with BTM with a mean age of 17.5±9.1 years from the Northwest of Iran. HFE gene mutations were analyzed using the polymerase chain reaction-restriction fragment length polymorphism method. Cardiac and hepatic hemosiderosis was assessed using T2*magnetic resonance imaging (MRI). Ferritin levels were measured using the enzyme immunoassay method.

Results

Ferritin levels showed a strong inverse correlation with hepatic T2*MRI values (r = -0.631, p = 0.001) but a poor correlation with cardiac T2*MRI values (r = -0.297, p = 0.044). The correlation between cardiac T2*MRI values and hepatic T2*MRI values was poor and insignificant (r = 0.287, p = 0.058). Genotype and allele distribution of HFE H63D and C282Y mutation did not differ significantly between patients with and without hepatic or cardiac hemosiderosis (p > 0.050). However, carriers of HFE 63D allele had significantly higher ferritin levels compared with non-carriers (1 903±993 vs. 992±683, p < 0.001).

Conclusions

Cardiac T2*MRI values showed a poor correlation with hepatic T2*MRI values and ferritin levels. Accurate assessment of cardiac iron overload in patients with BTM can only be done using the T2*MRI technique. Additionally, HFE H63D is a significant determinant factor for elevated ferritin levels in BTM patients.

Effect of the Hemochromatosis Mutations on Iron Overload among the Indian β Thalassemia Carriers

BACKGROUND

Hereditary hemochromatosis is a disorder of iron metabolism characterized by increased iron absorption.HFE gene mutations C282Y and H63D are responsible for the majority of hereditary hemochromatosis cases.

METHODS

We tried to look at the effect of HFE mutations on the iron status. A total of 100 β thalassemia traits (BTT) with 100 normal individuals were screened for the C282Y and H63D mutations using PCR-RFLP. The serum ferritin levels were determined using ELISA kit.

RESULTS

We did not find the C282Y mutation in our study group. The allelic frequencies for H63D mutation did not differ significantly between β-thalassemia traits (8.5%) and normal controls (9%). ΒΤΤ with H63D genotype of H/D (143.16 ± 80.3 ng/ml) and D/D (504 ng/ml) showed higher ferritin levels as against H/H genotype (88.64 ± 92.43 ng/ml). The statistically significant difference was observed in the mean serum ferritin levels among the individuals showing H/H and D/D genotypes (P < 0.002) and H/D and D/D genotype (P < 0.01) in both the groups.

CONCLUSION

This suggests that iron load in BTT tends to aggravated with the co-inheritance of the H63D mutation. The mutant H63D gene showed the presence of haplotype 6 which is reported in the European population suggesting a common origin.

Survey of Hfe Gene C282Y Mutation in Turkish Beta-Thalassemia Patients and Healthy Population: A Preliminary Study

Objective: This study was planned in order to determine the effect of C282Y mutation in development of secondary hemochromatosis in beta-thalassemia patients and to determine the prevalence and allele frequency of this mutation in a healthy control group.

Materials and Methods: Eighty-seven children and young adults (46 males and 41 females; mean age: 15.6±6.1 years, range: 3-30 years) with beta-thalassemia major (BTM) and 13 beta-thalassemia intermedia (BTI) patients (6 males and 7 females; mean age: 19.6±3.5 years, range: 13-26 years) were included in the study. The control group comprised 100 healthy blood donors.

Results: Neither heterozygous nor homozygous HFE gene C282Y mutation was detected in patients with BTM or BTI, or in control group.

Conclusion: The C282Y mutation, which is supposed to be responsible for the majority of hereditary hemochromatosis, was not found to have a role in the development of hemochromatosis in beta-thalassemia patients and was not detected in a healthy Turkish population. However, research on larger cohorts of individuals is required in order to determine the exact prevalence of the HFE gene mutation in Turkish populations from diverse ethnic origins and whether it would have an impact on iron loading in thalassemic populations.

Lack of association of primary iron overload and common HFE gene mutations with liver cirrhosis in adult Indian population

AIM

To find out the association of common HFE mutations (viz., C282Y and H63D) with primary iron overload (PIL) in liver cirrhosis (CLD) patients of Indian origin.

METHODS

Polymerase chain reaction-restriction fragment length polymorphism method was used for screening C282Y and H63D mutation in 496 CLD patients (hepatitis B virus associated cirrhosis (HBVc) = 74, hepatitis C virus associated cirrhosis (HCV) = 50, alcoholic cirrhosis with hepatitis (ALcW)  =  38, alcoholic cirrhosis without hepatitis (ALc) = 92, cryptogenic cirrhosis (CC) = 242) and 502 healthy controls. Transferrin saturation of >45 or serum ferritin of >300 ng/mL (males)/>200 ng/mL (females) with normal total exogenous iron intake was suggestive of PIL. Histological liver iron grading was done by Perl's Prussian blue stain.

RESULTS

Of 496 patients, 13 (2.6; 9 CC, 2 ALc, 1 HBVc, 1 AlcW) had PIL. However, only two (15.3) of 13 patients (1 CC and 1 HBVc) were positive for H63D heterozygous mutation. All the subjects were found to be C282Y wild type, except a single case of double heterozygous (C282Y/H63D) who however, did not have PIL. Overall frequency of H63D allele in patients and controls was not significantly different (5.95 and 4.58 respectively, p = 0.17). A highly significant H63D allele frequency (p  <  0.005) was observed in HBVc (10.82) and ALcW (11.84) groups but they were not associated with PIL.

CONCLUSION

The frequency of PIL, and the HFE gene mutaion (C282Y) are both rare in Indian patients and explain why hemochromatosis is a rare cause of liver cirrhosis in India. A highly significant H63D allele frequency in HBV and alcohol-related cirrhosis suggest a possible predisposing role for liver fibrosis of this allele.

Iron overload in the Asian community

Hereditary hemochromatosis is an iron overload disorder that can lead to the impairment of multiple organs and is caused by mutations in one or more different genes. Type 1 hemochromatosis is the most common form of the disease and results from mutations in the HFE gene. Juvenile hemochromatosis (JH) is the most severe form, usually caused by mutations in hemojuvelin (HJV) or hepcidin (HAMP). The autosomal dominant form of the disease, type 4, is due to mutations in the SLC40A1 gene, which encodes for ferroportin (FPN). Hereditary hemochromatosis is commonly found in populations of European origin. By contrast, hemochromatosis in Asia is rare and less well understood and can be masked by the presence of iron deficiency and secondary iron overload from thalassemia. Here, we provide a comprehensive report of hemochromatosis in a group of patients of Asian origin. We have identified novel mutations in HJV, HAMP, and SLC40A1 in countries not normally associated with hereditary hemochromatosis (Pakistan, Bangladesh, Sri Lanka, and Thailand). Our family studies show a high degree of consanguinity, highlighting the increased risk of iron overload in many countries of the developing world and in countries in which there are large immigrant populations from these regions.

Analysis of the HFE gene (C282Y, H63D and S65C) mutations in a general Chinese Han population

Hereditary hemochromatosis (HH) is one of the most common autosomal recessive genetic disorders of iron metabolism in white populations, which leads to inappropriately high iron absorption. C282Y, H63D, and S65C are three major missense mutations of the hemochromatosis gene (HFE). In the present study, C282Y, H63D, and S65C mutations in 395 normal Chinese Han populations from Zhejiang province were investigated. No C282Y, S65C mutations, and H63D homozygote was observed, while the genotype frequency of H63D heterozygote was 4.6% and the allelic frequency 2.3% in this population. This was the first report to analyze the prevalence of C282Y, H63D, and S65C mutations in the HFE gene in a Chinese Han population. Low incidence of the HFE gene mutations could be a reason for the rarity of HH in the Chinese Han population studied.