[Adrenal enzyme deficiency]

The defect in 21-hydroxylase is responsible for 95% of the congenital adrenal hyperplasia. It is a recessive autosomic genetic disease with two major clinical presentation. The classical presentation is severe and frequent. It associates an adrenal deficiency with sexual ambiguity in the girl. The diagnosis is easy by measuring the plasma level of 17 OH progesterone in antenatal, perinatal samples. The non classical presentation are less severe and are clinically expressed later during the life by an hyperandrogenic syndrome. The diagnosis requires an ACTH test. In any cases, the responsible mutations on the gene CYP21 are now well known and could be identified easily by molecular biology technics. By combinating hormonal and molecular tests, it is now possible to predict the clinical form of the disease in the context of a prenatal diagnosis, which can lead to a prenatal treatment.