Prenatal diagnosis of sickle cell anemia and beta-thalassemia in southern Turkey.

Hemoglobinopathies are the most common genetic diseases in Turkey. The incidence of sickle cell trait is 10.0% and beta-thalassemia (beta-thal) trait is 3.7% in the Cukurova region of southern Turkey. Sickle cell anemia is prevalent in the Cukurova region, but beta-thal is seen all over the country. A prenatal diagnosis center was established in 1992 at Adana, Turkey, for the prevention of sickle cell anemia and beta-thal. Fifteen hundred and seventy-five fetuses were examined at the Cukurova University Hospital, Adana, Turkey. Three hundred and eighty-six fetuses were diagnosed as homozygous or compound heterozygous for sickle cell anemia and beta-thal. A total of 15 different beta-thal mutations were characterized in the parents. The incidence of the IVS-I-110 (G > A) mutation accounted for about 50.0% of the parents with beta-thal trait. Twenty-four different genotypes were observed in this study. A total of 286 fetuses were diagnosed with homozygous sickle cell disease, 57 fetuses were beta-thal homozygotes, 25 fetuses were compound heterozygotes with Hb S [beta6(A3)Glu-->Val, GAG > GTG], and 18 of the fetuses were double heterozygotes for beta-thal mutations.