A. Muniz et al., beta-Thalassaemia in Cubans: Novel allele increases the genetic diversity at the HBB locus in the Caribbean, AM J HEMAT, 64(1), 2000, pp. 7-14
In order to establish the molecular basis of beta-thalassaemia in Cubans, a
total of 75 unrelated individuals, with beta-thalassaemia major (7), Hb S-
beta-thalassaemia (28), Hb C-beta-thalassaemia (1), and beta-thalassaemia t
rait (39) yielding 82 beta-thalassaemia alleles, were analyzed. Seventeen d
ifferent point mutations were identified accounting for 93% of the beta-tha
lassaemia alleles studied, revealing a high genetic heterogeneity at the HB
B 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 an
cestry of the extant Cuban population. We also report the identification of
a novel allele, IVS-I-108 (7 --> C), that possibly activates a cryptic bra
nch site, in a beta-thalassaemia carrier with no other molecular defect wit
hin the beta-globin gene and its proximal promoter. This study shows that p
renatal diagnosis of beta-thalassaemia should be feasible in about 60% of a
t-risk pregnancies by direct detection of selected point mutations. However
, due to the wide spectrum of mutations, and in order to offer fully inform
ative prenatal diagnosis to more than 87% of at-risk couples, the screening
for beta-thalassaemia mutations in Cubans should be performed by using a g
eneral point mutation detection method, such as DGGE (denaturing gradient g
el electrophoresis), Am. J. Hematol. 64:7-14, 2000. (C) 2000 Wiley-Liss, In
c.