Prenatal diagnosis of β-thalassaemia mutations using the reverse dot blot technique

Background. β-thalassaemia is the most common genetic disorder among Indians and a number of mutations causing this disease have been reported. Since effective treatment of thalassaemia major is complicated and very expensive, prenatal diagnosis has become an important option for those at risk of having an affected foetus. We report the use of a rapid hybridization method called 'reverse dot blot' for detection of specific mutations of the β-globin gene. Methods. DNA was obtained from a 12-week-old foetus by chorionic villus sampling and was amplified using specific primers by the polymerase chain reaction and analysed by the reverse dot blot test. Results were available within 36 hours after sampling. Result. The father and mother were found to be heterozygous for codon 15 (G-A) mutation of the β-globin gene. The foetus was normal. Conclusion. Reverse dot blot is a rapid and reliable technique for mutation detection in the β-globin gene and can be useful for antenatal diagnosis.