Haemoglobin S and β~(Thal): Their distribution in Maharashtra, India

摘要

It has been more than six decades since the first report of sickle cell anaemia in Indian subcontinent. Since then the researchers have been reported various haemoglobin varients prevalent in India, they are HbS, Hbβ~T, HbE and HbD. Earlier studies were confined to tribal and scheduled castes populations as if sickle haemoglobin was restricted to these two groups only. Since a decade or so, few studies on haemoglobinopathies from other Indian populations are available. Examination of premarital age group of 5172 Indian subjects (2762 males and 2410 females) from eastern Maharashtra of India showed high incidences of HbS (0-33 per cent) and Hbβ~T (0-10 per cent) in different ethnic groups. In present study cumulative gene frequency for HbS and Hbβ~T was found to be of 6.1 per cent and 2.3 per cent respectively. In present study sickle cell gene has been found in general categories of Indian populations besides scheduled castes and tribal populations. In Scheduled tribes HbS ranges from 0-24 per cent, in Scheduled castes and Nomadic tribal groups, HbS ranges from 0-13 per cent, in Other Backward caste categories it varies from 0-20 per cent while in higher caste populations it ranges from 0-5 per cent. The incidences of HbS are much higher among tribal groups than that found in other caste populations. The incidences of homozygous individuals are very few in HbS and Hbβ~T. The hitherto regional and populations specific Hbβ~T haemoglobin variant in Sindhi and Bengali communities is gradually spreading in other populations of Maharashtra as evident from the present study. Lesser value of MCV, MCH and MCHC in homozygous Hbβ~T is due to impairments of synthesis β-globin chain. The subject with the presence of β-thalassaemia is accompanied by raised level of HbA2. Unusual higher values of RBC and WBC suggest the high concentration of hypochromic microcytosis in anemia. The means of MCV MCH and MCHC in Hbβ~T are much lower than the normal ranges compared to HbS.