Low Prevalence of the HBB c.20A > T (HbS) Allele in a Turkish Cypriot Cohort: A Molecular Screening Study.

Sickle cell disease is caused by the HBB c.20A > T (p.Glu6Val; HbS) variant. Although Cyprus has a long-standing hemoglobinopathy prevention program, current population-specific data on HbS among Turkish Cypriots remain limited. Two hundred unrelated Turkish Cypriot adults were included. The HBB c.20A > T variant was genotyped by PCR-RFLP and confirmed by allele-specific real-time PCR. Genotype distribution was evaluated for Hardy-Weinberg equilibrium. No homozygous HbS genotype was detected. Three individuals were heterozygous carriers (AS), corresponding to a carrier frequency of 1.5%. The HbS allele frequency was 0.7%, and the genotype distribution was consistent with Hardy-Weinberg equilibrium (p = 0.916; chi-square = 0.011). HbS was uncommon in this Turkish Cypriot cohort. These findings support continued hemoglobinopathy surveillance and the integration of HbS counseling into existing premarital and population screening strategies, particularly as migration may alter local carrier frequencies over time.