β-Thalassemia in Bulgaria

Abstract

Analyses of DNA from 64 patients with thalassemia major using the hybridization technique of amplified DNA with radiolabeled synthetic oligonucleotide probes identified 13 different β-thalassemia mutations (Table I). the codon 39 (C ↣ T) and IVS-I-110 (G ↣ A) mutations occurred most frequently but seven additional mutations were observed which were present at frequencies of 3.9 to 10.2%. This broad spectrum of β-thalassemia alleles complicates the analyses for institutions involved in prenatal diagnosis. Promoter mutations were rare and the frequencies of two other mild mutations [IVS-I-6 (T ↣ C) and the poly A mutation] were relatively low indicating that β-thalassemia is a severe disease among Bulgarians. the high frequencies of 4.7-5.5% for the four frameshifts at codons 5, 6, 8, and 8/9 may be specific for this population.