[Molecular characterization of thalassemias in the Valencia community and its relationship with the hematological phenotype].

PURPOSE

The aim of the study is to present the first results of molecular characterization of thalassaemias in Valencian Community and their relationship with the haematological parameters.

PATIENTS AND METHODS

The study includes 87 thalassemic patients: 30 alpha-thalassaemias, 40 beta-thalassaemias and 17 delta beta-thalassaemias. The molecular alterations were studied in white cell blood DNA, either following different PCR methods or by testing the digestion of the amplified PCR products with selective restriction enzymes.

RESULTS

The molecular characterization of beta-thalassaemias was achieved in 94% of the subjects, being the transition C-->T in CD-39 the most frequent (44%) of the mutations studied. 94% of the delta beta-thalassaemias studied corresponded to the delta beta-Spanish type. All the alpha thalassaemias characterized (64%) corresponded to the -alpha 3.7 deletion. The reamining 36% were negative for the alpha 0 deletions --MED, --20.5, or the non deletional mutations Hph I and NocI.

DISCUSSION

In the Valencian Community, like what has been described for the beta-thalassaemias in other Mediterranean regions of Spain (Barcelona, Granada and Mallorca), a high incidence in C-->T transition in CD-39 was observed, in contrast with central and south-western regions of Spain, where the G-->A IVS-I-1 is the most frequent mutation. Our study supports that the IVS-I-6 mutations is the one with lower repercussions on the haematological parameters. Our study confirms the Spanish type of delta beta-thalassaemia as the most frequent in the Valencian Community, and that the 3.7 kb alpha deletion is the most frequent mutation for the alpha-thalassaemia, although alpha thalassaemia is also the poorly characterized form of thalassaemia.