MedGen

CMO type II deficiency is an autosomal recessive disorder caused by a defect in the final biochemical step of aldosterone biosynthesis, the 18-hydroxylation of 18-hydroxycorticosterone (18-OHB) to aldosterone. This enzymatic defect results in decreased aldosterone and salt-wasting associated with an increased serum ratio of 18-OHB to aldosterone. In CMO II deficiency, aldosterone can be low or normal, but at the expense of increased secretion of 18-OHB. These patients have a low ratio of corticosterone to 18-OHB (Portrat-Doyen et al., 1998). The CYP11B2 gene product also catalyzes an earlier step in aldosterone biosynthesis: the 18-hydroxylation of corticosterone to 18-OHB. A defect in that enzymatic step results in CMO type I deficiency (204300), an allelic disorder with an overlapping phenotype but distinct biochemical features. In CMO I deficiency, aldosterone is undetectable, whereas its immediate precursor, 18-OHB, is low or normal (Portrat-Doyen et al., 1998). [from OMIM]

CMO type I deficiency is an autosomal recessive disorder caused by a defect in the penultimate biochemical step of aldosterone biosynthesis, the 18-hydroxylation of corticosterone (B) to 18-hydroxycorticosterone (18-OHB). This enzymatic defect results in decreased aldosterone and salt-wasting. In CMO I deficiency, aldosterone is undetectable, whereas its immediate precursor, 18-OHB, is low or normal. These patients have an increased ratio of corticosterone to 18-OHB (Portrat-Doyen et al., 1998). The CYP11B2 gene product also catalyzes the final step in aldosterone biosynthesis: the 18-oxidation of 18-OHB to aldosterone. A defect in that enzymatic step results in CMO type II deficiency (610600), an allelic disorder with an overlapping phenotype but distinct biochemical features. In CMO II deficiency, aldosterone can be low or normal, but at the expense of increased secretion of 18-OHB. These patients have a low ratio of corticosterone to 18-OHB (Portrat-Doyen et al., 1998). [from OMIM]