[Carrier detection and prenatal diagnosis in phenylketonuria, cystic fibrosis and adrenal hyperplasia use of molecular biology techniques].

With the advent of molecular biology techniques the prenatal diagnosis of many inherited diseases is now possible. In our Division of Transplantation Immunology we provide prenatal diagnosis for phenylketonuria (PKU), cystic fibrosis (CF) and congenital adrenal hyperplasia (CAH). In CF and PKU the chromosome carrying the disease gene is identified by the molecular probe, while in CAH it can also be determined by HLA phenotyping. Accurate diagnosis of a disease is dependent on the physical distance on the chromosome between the probe and the disease gene. Chorionic villous sampling allows evaluation of embryos at 9-10 weeks of gestation and also identification of carriers. DNA prepared from white blood cells of members of 4 families with CAH was digested with restriction endonucleases. Southern transfers were hybridized with the probe for 21-hydroxylase, and with 3 HLA probes mapped to both sides of the gene for 21-OH. In 2 families the embryo was found to be normal and in 2 diseased. Using the same techniques, but with probe and endonucleases specific for PKU, prenatal diagnosis was provided for 11 families with that condition. An embryo with PKU was found in each of 2 families, normal ones in 7, and in the remaining 2 families the testing was not informative. As of the present, 6 normal and 2 diseased children have been born, all as predicted. In 8 families with CF, DNA was examined with 5 probes mapped to both sides of the CF gene. Carriers and healthy sibs were identified, and in 1 family prenatal diagnosis was provided.