β-Thalassaemia in Cubans: Novel allele increases the genetic diversity at theHBB locus in the Caribbean
✍ Scribed by Muñiz, Adriana; Martinez, Gisela; Lavinha, João; Pacheco, Paula
- Publisher
- John Wiley and Sons
- Year
- 2000
- Tongue
- English
- Weight
- 126 KB
- Volume
- 64
- Category
- Article
- ISSN
- 0361-8609
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✦ Synopsis
In order to establish the molecular basis of -thalassaemia in Cubans, a total of 75 unrelated individuals, with -thalassaemia major (7), Hb S--thalassaemia (28), Hb C-thalassaemia (1), and -thalassaemia trait (39) yielding 82 -thalassaemia alleles, were analyzed. Seventeen different point mutations were identified accounting for 93% of the -thalassaemia alleles studied, revealing a high genetic heterogeneity at the HBB locus in this population. The more prevalent mutations, namely, CD 39 (C → T) (30.5%), -29 (A → G) (13.4%), IVS-I-110 (G → A) (8.5%), and IVS-II-1 (G → A) (8.5%), reflect the Mediterranean and African predominant ancestry of the extant Cuban population. We also report the identification of a novel allele, IVS-I-108 (T → C), that possibly activates a cryptic branch site, in a -thalassaemia carrier with no other molecular defect within the -globin gene and its proximal promoter. This study shows that prenatal diagnosis of -thalassaemia should be feasible in about 60% of at-risk pregnancies by direct detection of selected point mutations. However, due to the wide spectrum of mutations, and in order to offer fully informative prenatal diagnosis to more than 87% of at-risk couples, the screening for -thalassaemia mutations in Cubans should be performed by using a general point mutation detection method, such as DGGE (denaturing gradient gel electrophoresis). Am.