UTILITY OF THE POLYMERASE CHAIN-REACTION (PCR) FOR PRENATAL-DIAGNOSIS OF GENETIC-DISEASE

Gene amplification by the polymerase chain reaction (PCR) has been applied to prenatal diagnosis for alpha and beta-thalassemias (1 and 5 cases respectively), Hemoglobin (Hb) Lepore/beta-thalassemia (1 case) and cystic fibrosis (14 cases). Chorionic villus samples were obtained in the tenth week of pregnancy and DNA analysed in parallel with conventional gene mapping. Direct diagnosis of the common Mediterranean beta-thalassemia mutations (IVS-1-110 and codon 39), Hb Lepore, and the DELTA-F508 mutation causing cystic fibrosis was achieved by hybridization of amplified material with pairs of allele-specific oligonucleotide (ASO) probes or by restriction enzyme digestion of PCR products. Results were confirmed by DNA mapping. Definitive diagnosis or exclusion of an affected fetus was possible in 17 of 21 cases thus examined. PCR reduces the time required for prenatal diagnosis. DNA contamination is a potential source of error.