Alpha-thalassaemia prenatal diagnosis by two PCR-based methods

In Cyprus all couples carrying alpha (0)-thalassaemia mutations are detecte d in the course of the thalassaemia carrier screening program and prenatal diagnosis is offered to all of them. Prenatal diagnosis for alpha -thalassa emia is routinely done by two independent molecular methods. With the first method, the mutations of the parents are directly determined by gap-PCR an d then the chorionic villus sample (CVS) is examined for the presence of th ese mutations. With the other method, a (CA)(n) repeat polymorphic site loc ated between the psi alpha (1)- and alpha (2)-globin genes is used for dete rmining the presence or absence of the normal and mutant alleles. In the pe riod from 1995 to 1999, molecular analysis of 46 couples in which haematolo gical data were consistent with deletion of two alpha -globin genes in both partners indicated that only 13 of them were actually at risk for haemoglo bin (Hb) Bart's hydrops fetalis and prenatal diagnosis was provided in 16 p regnancies. The molecular diagnosis was possible in all cases with the use of both gap-PCR and (CA)(n) repeat polymorphisms analysis. No misdiagnosed cases for alpha -thalassaemia have been reported to date. Copyright (C) 200 1 John Wiley & Sons, Ltd.