Molecular Characterization of α‐Thalassemia in Pakistan

Abstract

Common α‐thalassemia (thal) rearrangements were studied in a normal random population and in six ethnic groups of Pakistan. Analyses of 204 individuals from the normal population revealed the presence of only the −α3.7 allele with an overall frequency of 8.3%. Ethnic differences were statistically significant for Pashtoon vs. Balochi (p < 0.0005) and Pashtoon vs. Sindhi (p < 0.002). Two hundred and eighty‐five thalassemia patients were also studied to identify rare α‐thal alleles. In this group, 24.6% of the patients had one or two α genes deleted. Two rare alleles in the Pakistani population, −α4.2 (0.2%) and αααanti 3.7 (0.9%), were identified in these patients. The −α4.2 allele was found only in Sindhis, while αααanti 3.7 was present in Punjabis, Sindhis and Balochis. Five patients with triplicated α genes were homozygous for either the β+ or the β0 genotype.