PRENATAL-DIAGNOSIS OF BETA-THALASSEMIA AMONG INDIANS USING DENATURINGGRADIENT GEL-ELECTROPHORESIS

We have offered first trimester prenatal diagnosis to 55 couples at ri sk for beta-thalassemia, originating from various parts of India, usin g polymerase chain reaction and denaturing gradient gel electrophoresi s. Apart from the six common mutations, codon 30 (CA (G) under bar-->C A (A) under bar), Cap site +1 (A-->C), as well as three uncharacterize d mutations were seen among the parents. In the majority of cases, the diagnosis was possible by scanning only one fragment (B) where most o f the Indian mutations are situated. In 18 out of 55 cases, framework analysis could also have been used to offer prenatal diagnosis without characterizing the beta-thalassemia mutations. In the two cases where the mutations were uncharacterized, prenatal diagnosis was done only on the basis of the anomalous denaturing gradient gel electrophoresis patterns seen in the parents and in previously affected children. This is the first attempt of prenatal analysis using denaturing gradient g el electrophoresis in the extremely diverse Indian population where th e profile of mutations has not yet been fully elucidated.