Prenatal diagnosis of 21-hydroxylase deficiency by RFLP analysis of the 21-hydroxylase, complement C4, and HLA class II genes.

In 19 pregnancies at risk for 21-hydroxylase deficiency (21OHD) in 18 families with at least one affected child, prenatal diagnosis was performed by RFLP analysis using the enzymes Taq I and EcoRI and the DNA probes specific for the 21OH genes, the closely linked complement C4 genes and the highly polymorphic HLA class II genes DRB, DQB, and DPB. For fetal DNA analysis either chorionic villi or cultivated amniotic cells were used. In all 19 cases, a clear prenatal diagnosis was possible either with the 21OH probe alone or in most cases, by combining the results of the different closely linked loci.