Prevalance of H63D and C282Y Mutation and Its Association with Iron Overload in Thalassemia Patients in an Eastern Indian Population
Anindya Dasgupta
Department of Biochemistry, Calcutta National Medical College, Kolkata, India.
Suparna Roy *
Department of Biochemistry, Calcutta National Medical College, Kolkata, India.
Manali Sinharay
Department of Biochemistry, Calcutta National Medical College, Kolkata, India.
*Author to whom correspondence should be addressed.
Abstract
Aims: Iron overload in beta thalassemia is linked to different mutations in diverse population groups. Among them polymorphism of C282Y and H63D in the Hfe gene are particularly important. The present study was undertaken to evaluate the prevalence of the H63D and C282Y mutation and their effects on iron deposition in beta-thalassemia patients in our region having a high prevalence of the disease.
Study Design: Hospital based, observational, case control study in patients of beta thalassemia major.
Place and Duration of the Study: Department of Biochemistry of a medical college and hospital in Kolkata during April 2016 to April 2017.
Methodology: Cases were diagnosed for beta thalassemia major using HPLC. DNA was purified from whole blood in 210 cases and 104 controls and Hfe gene was studied for H63D and C282Y polymorphisms after amplification by PCR followed by restriction digestion using appropriate restriction enzymes. Allelic differences between two groups were assessed by chi square and odd ratio test. Any potential link between the polymorphic variations and iron deposition were assessed by post hoc ANOVA of serum ferritin levels among the three genotypes.
Results: For C282Y polymorphism, all 210 cases were homozygote for the G allele. For H63D mutation, 16, 186 and 8 cases were heterozygotes (CG), homozygotes (CC) and of mutant variant (GG) respectively, the difference being insignificant between the case and control group (χ2 = 1.44, P= .486). Allelic difference of Gand C between the two groups were also insignificant (χ2 = 0.09, P = .76; OR range of 0.72 to 1.98 at 95% CI). Post hoc ANOVA showed significant difference in the serum ferritin values between the GG and CC genotype and GC and CC genotype (P =.001) in the case group.
Conclusions: Our study population was not at risk for iron deposition from the C282Y mutation. However, 92 percent of cases showed wild CC alleles for the H63D mutation that showed significantly higher amount of iron deposition. We suggest that this mutation has a higher penetrance in our study population suffering from beta thalassemia.
Keywords: Beta thalassemia, Hfe gene, C282Y mutation, H63D mutation, iron overload, serum ferritin