Prenatal diagnosis of 21-hydroxylase deficiency by the complementary deoxyribonucleic acid probe for cytochrome P-450C-21OH.

The availability of the complementary deoxyribonucleic acid probe for cytochrome P-450C-21OH and the identification of specific gene defects in some families with congenital adrenal hyperplasia have made prenatal diagnosis feasible. Deoxyribonucleic acid samples from amniocytes of a fetus at 16 weeks' gestation, one previously affected son, and their parents were digested with the restriction enzymes Tag1 [corrected] or EcoRI and hybridized to the cytochrome P-450C-21OH complementary deoxyribonucleic acid probe. The previously affected son and the fetus both lacked the Tag1 [corrected] 3.7 kb band. At the time of delivery, the second child had a cord blood 17 alpha-hydroxyprogesterone level of 8000 ng/dl. The absence of the 3.7 kb Tag1 [corrected] fragment in affected members of this family made possible the use of deoxyribonucleic acid analysis for prenatal diagnosis.