Genetics of steroid 21-hydroxylase deficiency

Classical and non-classical adrenal hyperplasia due to steroid 21-hydroxylase deficiency (210HD) are HLA-linked, autosomal recessive disorders characterized by a variable degree of hyperandrogenism and cortisol deficiency. Direct screening of newborns has placed the incidence of the classical disease at 1 : 5000 to 1 : 15 000, whereas the nonclassical form of the disease is estimated to occur in 1 : 100 Caucasians. Molecular genetic analysis has revealed that salt-wasting classical 210HD linked to HLA-Bw47 is associated with a deletion of one of two 21-hydroxylase genes.