α-Thalassemia in Oraons-indigenous tribal population from Jharkhand, India: insights to common deletions.

Alpha thalassemia is a common inherited blood disorder worldwide, with varying prevalence among different populations. This study investigates the prevalence and spectrum of alpha thalassemia deletions in the Oraon tribe, one of the largest indigenous populations in central-eastern India. Two hundred and twenty-seven Oraon individuals were genotyped using multiplex PCR for seven common alpha-globin gene deletions and triplications. Hematological profiling was performed on automated cell counter. A high frequency of alpha globin gene deletions was observed in the Oraon population, with the -α3.7 deletion being predominant. The homozygous -α3.7/-α3.7 genotype was found in 32.6% of Oraons, significantly higher than in other tribes. Compound heterozygosity (-α3.7/-α4.2) was also common (15.4%). Hematological analysis revealed significant differences between genotypes, with -α4.2/-α4.2 individuals displaying lower hemoglobin levels. One individual with HbH disease (--SA/-α³·⁷) was identified with characteristic hematological features. The high prevalence of alpha thalassemia deletions in Oraons may reflect historical malaria selective pressure. These findings have important implications for public health strategies and clinical management of hemoglobinopathies in this community. The study underscores the genetic complexity of alpha thalassemia in indigenous populations and highlights the need for comprehensive screening approaches. Further research including non-deletional mutations is needed to provide a complete spectrum of α-thalassemia in this population.