Molecular characterization of á-thalassaemia mutations in Guadeloupe - abstract

ABSTRACT

In order to delineate the spectrum of á-thalassaemia (á-thal) mutations in the Guadeloupean population, we have analysed a representative sample of 59 unrelated families carrying a á-thalassaemia trait. Using gene amplification, hybridization with 32P-labelled oligonucleotide probes and sequencing of amplified DNA, 8 different á-thal mutations were identified in 62 members of 36 families. Four of these families carried a á§-thal trait whereas, in the 32 others, a á+-thal trait has been identified. All patients were á-thal heterozygous 30 had Hb S/á-thal, 1 had Hb C/á-thal, 1 had HPFH/á-thal whereas the remaining 30 had a Hb A/á-thal genotype. Four of the á-thal mutations detected [-29 (A -> G), IVS-I-5 (G -> C), IVS-II-1 (G -> A) and CD 24 (T -> A)] accounted for approximately 88.8 percent of the á-thalassaemia chromosomes identified. The four other variants, -88 (C -> T), IVS-I-5 (G -> A), IVS-I-5 (G -> T) and IVS-I-2 (T -> C), are less frequent. The á-thalassaemia mutations in 23 families remained unidentified and are under investigation. This study provides data for prenatal diagnosis of sickle-cell disease for Hb S/á-thalassaemia genotypes (AU)