Congenital adrenal hyperplasia.

The enzyme defects of steroidogenesis appear to be monogenic disorders. The clinical heterogeneity of these disorders suggests allelic variations at the loci for these disorders, as has been reported for other gentic inborn errors. When the genes for these enzymes are cloned and sequenced, the final proof of allelism will be obtained. Prenatal diagnosis of one of the enzyme defects is possible by biochemical and HLA studies of the amniotic fluid. In the others, DNA restriction fragment polymorphism may provide a tool in the future for prenatal diagnosis. Since all these disorders are compatible with normal intelligence and a productive life, the more frequent ones at least are worthy of screening for early diagnosis and treatment.