Distribution Pattern of Mutations Causing β-Thalassemia in Districts Swabi and Mansehra, Pakistan

Abstract

The present study analyzed 100 alleles from 50 unrelated families from Districts Swabi and Mansehra through ARMS PCR for the nine most common mutations in the gene for β-globin (HBB), reported in Pakistan. In general, 89% of alleles were completely characterized, and 11% remained uncharacterized. More specifically, in samples collected from Swabi, 08% of mutations remained uncharacterized, and 92% were characterized entirely, while in samples from Mansehra, 86% of the total alleles were characterized, and 14% remained uncharacterized. Overall, the IVSI-5 (G>C), with a frequency of 33%, was identified as the most prevalent, while IVSI-1 (G>A), with a frequency of 0.0%, was the least prevalent allele. The frameshift codons 8/9 (+G) [also known as FSC- 8/9 (+G)] and Cd (codons) 41/42 (-TTCT) alleles were observed to be the second and third most common alleles, respectively. The 619 bp deletion accounted for nine percent of the total alleles investigated. In Mansehra, the IVSI-5 (G>C) was found to be the most predominant allele. The same allele was observed as the second most common allele in Swabi, where the FSC- 8/9 (+G) was found to be the most prevalent type. The FSC- 8/9 (+G) was the second most common mutation in Mansehra. These variations in mutation rates could be attributed to the small sample size or possibly to the different genetic backgrounds of these two regions.