Prevention of homozygous beta thalassemia by premarital screening and prenatal diagnosis in India

Abstract

To determine the feasibility and acceptability of premarital screening for beta thalassemia/related hemoglobinopathies followed by prenatal diagnosis in India. Premarital testing for thalassemia carrier state was carried out in (1) extended family members (EFM) of diagnosed cases of thalassemia/hemoglobinopathies, (2) unmarried adult cases of anemia attending the hospitals' outpatient department (OPD) and (3) adult college students (CG). Hemoglobin, red cell indices were measured by a cell counter and hemoglobin fractionation was carried out by high performance liquid chromatography (HPLC). In cases with HbA2>3.5%, or with variant hemoglobin, mutation screen was done by amplification refractory mutation system polymerase chain reaction (ARMS-PCR). In high-risk prospective couples, premarital genetic counseling was done and prenatal diagnosis possibilities were explained. The yield of carriers from EFM, OPD and CG groups was 78.17% (308/394), 19.51% (263/1348) and 4.04% (38/939), respectively. The number of prospective high-risk couples detected were 154, 48 and 2 from EFM, OPD and CG, respectively. As much as 99% of prospective carrier couples married even after knowing their high-risk status and opted for prenatal diagnosis. The program averted the birth of 33 thalassemic children; 28 in EFM group (by screening of 394 individuals), 4 in the OPD group (by screening 1348 anemic patients), and 1 in CG group (by screening of 939 students). Premarital screening in extended family members, followed by prenatal diagnosis is acceptable and the most effective strategy for control of thalassemia in developing countries like India.