A single, large deletion accounts for all the beta-globin gene mutations in twenty families from Sabah (North Borneo), Malaysia. Mutation in brief no. 240. Online

• Published in: Human mutation Vol. 13; no. 5; p. 413
• Main Authors: Thong, M K, Rudzki, Z, Hall, J, Tan, J A, Chan, L L, Yap, S F
• Format: Journal Article
• Language: English
• Published: United States 1999
• Subjects: beta-Thalassemia - genetics; Blotting, Southern; Gene Deletion; Globins - genetics; Humans; Malaysia; Phenotype; Polymerase Chain Reaction; Sequence Analysis, DNA; Malaysia
• ISSN: 1059-7794
• DOI: 10.1002/(SICI)1098-1004(1999)13:5<413::AID-HUMU14>3.0.CO;2-H

Beta-thalassemia major is one of the commonest genetic disorders in South-East Asia. The spectrum of beta-thalassemia mutations in the various ethnic sub-populations on the island of Borneo is unknown. We studied 20 Dusun children from the East Malaysian state of Sabah (North Borneo) with a severe beta-thalassemia major phenotype, using a combination of Southern analysis, polymerase chain reaction analysis and direct sequencing. We found the children to be homozygous for a large deletion, which has a 5' breakpoint at position -4279 from the cap site of the beta-globin gene (HBB) with the 3' breakpoint located in a L1 family of repetitive sequences at an unknown distance from the beta-globin gene. This was similar to a recent finding of a large deletion causing beta-thalassemia first described in unrelated beta-thalassemia heterozygotes of Filipino descent. This report describes the first 20 families with homozygosity of the deletion causing a severe phenotype. It provides the first information on the molecular epidemiology of beta-thalassemia in Sabah. This finding has implications for the population genetics and preventative strategies for beta-thalassemia major for nearly 300 million individuals in South-East Asia.