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Hemoglobinopathies are the most commonly inherited genetic disorders in India. Certain communities in India have a high predisposition to beta-thalassemia. To offer prenatal diagnosis and to prevent the birth of an affected child, mutation testing in clinically diagnosed beta-thalassemia patients/carriers is a prerequisite. Over a period of 4 years, we have conducted DNA analysis in 385 carriers for 15 beta-thalassemia mutations, HbD, HbE, and HbS. Using reverse dot blot (RDB) and amplification refractory mutation system (ARMS), we have been able to identify mutations in 381 of 385 thalassemia chromosomes. The study included the analysis of five common mutations found in Asian Indians, namely IVS1-5 (G-C), 619-bp deletion, IVS1-1 (G-T), and the frameshifts at CD8/9(+G) and CD41/42(-CTTT). The occurrence of these five mutations was seen in 299 (91.2%) carriers referred to us, the percentage of mutations varying between 4.0 and 68.9%. We also found Cd16 (-C) in 2.1%, CD30 (G-C) in 1.5%, and CD 15(G-A) in 0.6%; these are considered common mutations in the Indian population, as well. The beta-thalassemia anomaly in 4 (0.6%) carriers remained uncharacterized by RDB and ARMS analysis. During delineation of the mutations in uncharacterized carriers by single-stranded conformational polymorphism (SSCP) and sequencing analysis, we have also been able to identify two unusual mutations, one involving an initiation codon and the second involving a novel 8-bp deletion, in Indian families of Uttar Pradesh origin.

The beta-thalassemias are a heterogeneous group of hereditary anemias. A multitude of mutations have been reported, resulting in varied phenotypes. In each ethnic group there is always a subset of common, less common, and rare mutations, which makes population screening, prenatal diagnosis, and genetic counseling easier. In this paper we report a rare beta-thalassemia mutation found in an Indian subject by SSCP and sequencing analysis. The mutation, initiation ATG --> ACG, was found in heterozygous condition in a patient belonging to Brahmin family of Uttar Pradesh origin. Haplotype analysis was performed to identify the chromosomal background associated with the mutation and to tracing the origin and spread of the mutation. This study, as previous studies, suggests that rare beta-thalassemia mutations, such as the initiation codon mutations, have no set geographical distribution and are relatively recent., (Copyright 2002 Wiley-Liss, Inc.)