Molecular variants of G6PD deficiency among certain tribal communities of Orissa, India.

This study investigated the extent of molecular heterogeneity of the G6PD enzyme among certain aboriginal (tribal) populations of Orissa, an eastern Indian state, which is hyperendemic for Plasmodium falciparum malaria. A total of 3480 males from 14 tribal communities were screened, and 223 (6.4%) individuals were found to be G6PD deficient. Molecular analysis revealed that 59.2% of deficient individuals had the G6PD Orissa mutation and 37.2% had the G6PD Mediterranean mutation. The presence of G6PD Med has not been previously reported among the tribal populations of Orissa. Interestingly, both G6PD Med and G6PD Orissa were found among communities belonging to the Mundari (Austroasiatic) linguistic group, while G6PD Med was exclusive to Dravidian and G6PD Orissa to Indo-Aryan groups. Erythrocytic G6PD enzyme activity was severely reduced in the case of G6PD Med type (0.64-1.1 IU/g Hb) as well as among the uncharacterized samples, but was moderate in G6PD Orissa type (1.2-3.1 IU/g Hb). Anaemia was moderate among the individuals with G6PD Med mutation and mild among individuals with G6PD Orissa mutations. The prevalence of G6PD deficiency as well as molecular variants of the Gd- gene is highly heterogeneous among the tribal population of Orissa. The high endemicity of P. falciparum malaria has probably selected two different molecular variants of Gd- at different points in time, which is discussed.