PRENATAL-DIAGNOSIS OF BETA-THALASSEMIA BY COELOCENTESIS

Coelomic fluid and placental tissue were obtained from four women unde rgoing termination of pregnancy at 7-9 weeks gestation for psychologic al reasons. All four women and their partners were known carriers of b eta-thalassaemia and DNA analysis in their blood identified the mutati on carried by each of them. Allele-specific polymerase chain reaction and denaturing gradient gel electrophoresis techniques were used to de tect and identify the mutations in the DNA extracted from the coelomic cells and placental tissue. Three fetuses were found to be carriers o f either the paternal or maternal mutation, while one was found to be affected by beta-thalassaemia. There was concordance in the results ob tained from the chorionic villi and coelomic cells. Amplification of t he apolipoprotein B gene variable number tandem repeats (VNTR), in the DNA of the coelomic cells showed normal segregation of alleles in the fetuses, thus excluding maternal contamination. The results of this s tudy demonstrate that coelocentesis may be a reliable alternative tech nique for the diagnosis of beta-thalassaemia from as early as 7 weeks gestation.