Prenatal diagnosis of thalassemia in Azerbaijan

Abstract

Thalassemias and other hemoglobinopathies are the most common monogenic disorders in the world and the prevalence of β-thalassemia in Azerbaijan is 3.7-8.6%, while prevalence of α-thalassemia is 14%, 9%, and 5% in Gabala, Shaki and Baku respectively. Currently, there is no effective radical treatment of these disorders, therefore prevention programs including population screening and prenatal diagnosis are being applied in populations where hemoglobinopathy is widespread. Since 2015, prenatal diagnosis has been applied to all carrier couples identified through premarital screening. 170 couples have been referred to genetic counselling and they have been genotyped for the presence of HBB gene mutations between 2015-2019. 115 fetal specimens obtained through transabdominal amniocentesis were examined by molecular-genetic methods to identify the genotypes of the feti. 20 prenatal diagnosis were done in 2016, 24 in 2017, 57 in 2018 and 14 prenatal diagnosis were performed until March 2019. 29% of the couples were in consanguineous marriages (3rd degree relatives). Of the 115 fetal specimens examined, 61 were identified as heterozygous, 28 were homozygous or compound heterozygotes, and 26 were unaffected healthy pregnancies. All homozygous or compound-heterozygous pregnancies except multiple pregnancies (n=3) were terminated by selective abortion, and the incidence rate of the disease decreased significantly since the program started (IRR=0.6285, p<0.005, 95% CI [0.4928, 0.7993]; PF = 18.92%).