Congenital adrenal hyperplasia due to 21-hydroxylase deficiency is a disorder with different clinical manifestations, that results from mutations in the P-450(c21) gene. Direct sequence analysis of P-450(c21) genes in a family demonstrates that patients with different clinical forms of congenital adrenal hyperplasia can have identical P-450(c21) genes, suggesting that other effects play a role in developing the different clinical forms.