Beta-thalassaemia in south-western Spain: high frequency of G-->A (IVS I-1) mutation.

Huelva province is situated in southwestern Spain; its historic and geographic characteristics contribute to the existence of erythrocyte genetic anomalies, such as beta thalassaemia. We have carried out a prenatal study of microcytosis, with a preliminary beta-gene analysis. Our findings show a beta-thalassaemia trait prevalence of 0.81%. In the molecular research there was a high frequency of G-->A (IVS I-1) injury: 55%. By comparing the rates of this mutation neighbouring Cáceres province in western Spain (47%) and Algarve in south Portugal (32%), it demonstrates that this beta-gene defect has a high frequency in the southwest of the Iberian Peninsula.