Corticosterone methyloxidase type II (CMO-II) deficiency, also called 18-oxidase defiency or aldosterone deficiency II among other names, is a genetic disorder that is autosomally linked. It is caused by a mutation in the cytochrome P450 11B2 gene, whose protein product is responsible for the formation of aldosterone from 18-hydroxycorticosterone (18-OHB), as well as converting progesterone to 11b-hydroxyprogesterone. The conversion of 18-OHB to aldosterone is the only reaction that uses 18-OHB, and due to the enzyme not being entirely functional, it builds up in the cell, while aldosterone levels will be lowered. However, since progesterone and 11b-hydroxyprogesterone are both produced and used by other reactions, their levels in the cell are not changed as drastically. Compared to the CMO-I deficiency, the CMO-II deficiency has less severe mutations in the gene, which cause it to have less severe changes in aldosterone and 18-OHB concentrations. The CMO-II deficiency, and its resulting aldosterone deficiency can cause a salt-wasting phenotype in children, due to aldosterone being responsible for the resorption of sodium in the body, as well as secretion of potassium. With levels of aldosterone being lower due to this deficiency, excess sodium is excreted in the urine, and higher than average levels of potassium in the serum. Aside salt-wasting and potential failure to thrive as an infant due to this, there are no symptoms, such as genital abnormalities, that are seen in similar salt-wasting disorders like CYP21 deficiency.

Corticosterone Methyl Oxidase II Deficiency (CMO II) References

Steroidogenesis References