MOLECULAR-BASIS OF BETA-THALASSEMIA MINOR IN TAIWAN

The mutations producing beta-thalassemia minor in 227 Taiwanese were s tudied using the method of naturally an amplified created restriction sites. Beta-Thalassemia minor was caused by one beta-globin gene mutat ion in most of the cases (225/227); only a few cases were caused by tw o gene mutation (2/227). The most common type of mutation was frameshi ft codon 41/42 (-TCTT) (93/227), followed in descending order by the C -->T substitution at nucleotide 654 of IVS-2 (83/227), the nonsense mu tation A-->T at codon 17 (22/227), the A-->T mutation at position -28 of the promotor region (12/227), the frameshift codon 27/28 (+C) (6/22 7), the initial codon mutation (ATG-->AGG) (5/227), and one each of th e codon 71/72 (+A), IVS-1 nt 1 (G-->T), IVS-1 3' end (TAG-->GAG), and nonsense codon 43. In the two cases of the two-gene mutation, one was the nt 654 mutation with Hb Kaohsiung and another one was frameshift c odon 41/42 with Hb Meinung. The first four mutations accounted for mor e than 90% of the mutations. The C-->T substitution at the nt 654 of I VS-2 and initial codon mutation in our study had a higher incidence th an in other Southeast Asia areas. Comparison of clinical data in diffe rent types of beta-thalassemia showed that there were higher MCV and M CH levels in beta+-thalassemia.