Profile of β-thalassemia and its prenatal diagnosis in Khorasan-e-Jonobi Province, Iran.

This study was performed to determine the molecular spectrum of β-thalassemia (β-thal) mutations in at-risk couples from Khorasan-e-Jonobi Province in East Iran. During the past 9 years, 106 couples were referred to our Center for detection of their β-thal carrier status. Samples were initially tested for the most common Iranian α- and β-thal mutations by gap-polymerase chain reaction (gap-PCR) and amplification refractory mutation system (ARMS)-PCR, respectively. In cases with negative results, direct DNA sequencing was used to identify additional β-globin mutations. Fetal DNA was obtained from chorionic villus sampling (CVS) (n = 55), 47.2% were referred during pregnancy and 23.0% of couples underwent more than one prenatal diagnosis (PND). Of the 14 mutations that were detected in Khorasan-e-Jonobi Province, Iran, the IVS-I-5 (G>C) and codon 44 (-C) mutations were the most frequently identified variants, representing 45.9 and 24.8% of the total; these were followed by three mutations in the following order: -88 (C >T) (5.3%); codons 8/9 (+G), a rare mutation, and codons 37/38/39 [-7 nucleotides (nts)], each with a frequency of 4.5%. These findings provide complementary information on the region specific profile of β-thal in eastern Iran.