Characterization of beta-thalassaemia mutations in 57 beta-thalassaemia families seen at Lucknow.

As an initial step towards establishing prenatal diagnostic service for beta-thalassaemia in the state of Uttar Pradesh, we have investigated the prevalence of five common mutations reported from India in 57 families, each with an index patient of thalassaemia major, by amplification refractory mutation system (ARMS). Thirtyone of the 57 families (54.3%) hailed from Uttar Pradesh; 11 (19.3%) from Sindh in Pakistan, 6 (10.5%) from Punjab, 6 (10.5%) from North-West Pakistan and one each (1.8%) from Bengal, Madhya Pradesh and Bihar. In the 31 families from Uttar Pradesh, 29 were of beta-thalassaemia and 2 of HbE/beta-thalassaemia. IVS-1 nt 5 (G-C) mutation was the most common mutation in families native to Uttar Pradesh. This mutation was identified in 60 per cent (33 out of 55) of the obligate heterozygotes. Amongst the 43 obligate heterozygote carriers originating from Western India, the prevalence of IVS-1 nt 5 (G-C) mutation was 46.5 per cent; 619 bp deletion 23.3 per cent; Co 8/9 (+G) mutation 11.6 per cent and Co 41/42 (-CTTT) mutation 4.6 per cent. In 23.6 per cent of carriers from Uttar Pradesh and 7.0 per cent of carriers from Western India, none of the 5 mutations tested were detected. IVS-1 nt 1 (G-T) mutation was found in one family native to Sindh.