Prenatal Diagnosis of beta-Thalassemia in the Antalya Province

Beta-thalassemia and Sickle cell anemia are serious health problems in the Antalya Province of Turkey as well as WorldWide. We aimed to summarize data obtained from the prenatal diagnosis for beta-thalassemia and sickle cell anemia of 103 fetuses.All samples were cytogenetically and molecular genetically examined during a period of 4 years. Molecular testing using RDBH anddirect DNA sequencing was performed by using amplified DNA from chorionic villi samples at 9-14 weeks of gestation, whilemutations in the parents were determined in advance. Cytogenetic analysis was carried out from a primary culture set up. Of the103 fetuses, 26 were affected; 25 had beta-thalassemia major, and one had HbS/ beta-thalassemia. All of the affected fetuses weretheraupatically aborted with the written permission of their parents. VNTR analysis was used to eliminate maternal contamination.IVSI-110 (G-A) was reported as the most frequent allele(50.4%) in all fetuses. Heterozygosity for IVSI-110 was the most prevalentcombination. Of the 26 affected fetuses, one was found to have a 46,XY/47,XY,+22 mosaic karyotype. On the other hand, one fetuswith normal genotype for beta-globin gene was cytogenetically found to have a 45,X karyotype. As a result, we suggest that foraccurate genetic counselling the CV and other samples obtained for molecular prenatal testing of the beta-thalassemia should alsobe studied to identify possible chromosomal abnormalities