DNA haplotype heterogeneity of beta-thalassaemia in Greece: feasibility of prenatal diagnosis.
We have carried out DNA haplotype analysis of 69 beta-thalassaemia patients in Greece and 42 of the parents using seven standard polymorphic sites. Our data show a high degree of heterogeneity of the chromosomal background in which beta-thalassaemia occurs in Greece, suggesting a high degree of heterogeneity in the beta-thalassaemia mutations involved. Haplotype I is found here to represent 45% of total beta-thalassaemia mutations detected, a proportion well below the 67% reported in earlier studies with Greek-American patients. Nine different haplotypes are detected and the ones carrying beta(+) mutations are the majority, including those which are linked to beta(+) mutations associated with a thalassaemia intermedia phenotype, and which constitute 11% of all haplotypes. One of these haplotypes (---- ) has never before been reported to occur in non-Africans, whether in beta thal or beta A chromosomes, and it is found here to be of African origin rather than the product of recombination. In 21 families haplotype analysis showed that prenatal diagnosis for a second child was feasible in 81% of the cases. Use of the AvaII-psi beta polymorphic site as well as the seven standard ones brought this proportion up to 90%.
D002648:Child; D004247:DNA / Q000032:analysis*; D005240:Feasibility Studies; D005260:Female; D006115:Greece; D006239:Haplotypes; D006801:Humans; D008297:Male; D011247:Pregnancy; D011296:Prenatal Diagnosis; D013789:Thalassemia / Q000208:ethnology / Q000235:genetics*
D004247:DNA