Geographic and ethnic distribution of beta-thalassemia mutations in Uttar Pradesh, India

We have studied the geographic and ethinic distribution of mutations in 376 subjects who were carriers of beta-thalassemia, and identified the mutatio ns in 365 chromosomes. The majority of the beta-thalassemia carriers were o f Uttar Pradesh (India) origin. Their pattern of mutations differed from th e other states of India and from those families who had migrated from Pakis tan. The frequency of the TVS-I-5 (G-->C) and 619 bp deletion mutations wer e 64.3 and 2.5%, respectively, among families originating from Uttar Prades h, compared to a prevalence of 37.5 and 27.5%, respectively in the populati on of Pakistani immigrants. Of the 10 common Asian Indian mutations, only e ight were observed in subjects studied from different parts of India. By us e of the amplification refractory mutation system along with DNA sequencing techniques, the mutations were successfully identified in 97.1% of subject s, while 11 cases (2.9%) still remain to be characterized by single strand conformation polymorphism and sequencing analyses. The application of this knowledge has facilitated the successful implementation of the program of g enetic counseling and prenatal diagnosis of beta-thalassemia, thus helping to avoid the birth of an affected child in India.