[Genetic counseling and prenatal diagnosis of adrenal hyperplasia caused by 21-hydroxylase deficiency].

The close linkage recently discovered between 21-hydroxylase deficiency and genes of the HLA system has given a new impulse to genetic studies of congenital adrenal hyperplasia. Segregation of the deficient genes can now be followed within the families affected, which considerably enlarges the possibilities of genetic counselling, while prenatal diagnosis is facilitated by modern methods of HLA typing of amniotic fluid cells and by modern techniques of amniotic steroid assays.