Genotype-phenotype correlation of β-thalassemia spectrum of mutations in an Indian population.

Coexistence of thalassemia, hemoglobinopathies and malaria has interested geneticists over many decades. The present study represents such a population from the eastern Indian state of Orissa. Children and their siblings (n=38) were genotyped for β-thalassemia mutations and genotype-phenotype correlation was determined. The major genotype was IVS 1.5 mutation: 26% homozygous (n=10) and 37% (n=14) double heterozygous with other mutations or hemoglobinopathies. Sickle hemoglobin was the major associated hemoglobinopathy (n=12, 32%). Other mutations found were Cd 8/9, HbE and Cd 41/42. The study population did not contain any IVS 1.1 mutations which is the second major Indo-Asian genotype. Genotype-phenotype correlation revealed that genotypes of IVS 1.5, Cd 8/9 Cd 41/42 alone or in association, exhibit severe, moderate and mild severity of thalassemia, respectively. Identification of the mutation at an early age as a part of new born screening and early intervention may help reduce the thalassemia-related morbidity.