Molecular genetics and prenatal diagnosis of beta thalassemia to control transfusion dependent births in carrier Pakistani couples

Objective: to examine molecular genetics and prenatal diagnosis of beta-thalassaemia. methods: the study was conducted at the comsats institute of information technology,sahiwal,pakistan,from october 2012 to october 2013,and comprised families having children affected by thalassaemia and autosomal recessive β-thalassemia. blood samples of thalassaemic children and their parents were collected from different areas of pakistan. they were screened for reported mutations through amplification refractory mutation system-polymerase chain reaction. once mutation was characterised,chorionicvilus sampling was carried out to provide the retrospective first trimester prenatal diagnosis. results: a total of five families were included in this study. electropherogram showed that both mother and father were heterozygous (carrier) for intervening sequence i-5 mutation whereas the affected child was homozygous for this mutation. five chorionic villus samples were examined to analyse the molecular defects which were responsible for beta-thalassaemia in the families. prenatal diagnosis was performed for these families. they had at least one affected child (thalassaemia major) who was transfusion-dependant. amplification refractory mutation system-polymerase chain reaction was found to be a very sensitive method to find the known point mutations present in beta-globin gene. point mutations identified included intervening sequence i-5 (g-c),frameshift codon8/9 (+g) and frameshift codon-41/42 (-ttct). conclusion: it is the best preventive action to adopt the screening process to overcome the disease. © 2017,pakistan medical association. all rights reserved.