[Variability of corticosterone methyl oxidase (type II) deficiency. Presentation of three case reports]

We report on three cases of Corticosterone Methyl Oxidase Typ II deficiency in two siblings and one boy. All three children were presented with typical symptoms of a saltlosing syndrome (vomiting, poor drinking, weight loss, hypotonia). Hyponatremia and hyperkalemia, low plasma aldosterone concentrations when related to high plasma-renin-activities suggested deficiency in the final steps of aldosterone biosynthesis. Variable degrees of enzyme deficiency and no relation of biochemical findings to the clinical symptoms were observed. Clinical symptoms became less severe with age. Diagnosis of CMO II-deficiency was established by an abnormal high ratio of 18-hydroxycorticosterone to aldosterone, by measurement of their precursors and metabolites in plasma and urine. In one sibling negative values may have been caused by suppression of the renin-angiotensin-system due to high sodium replacement therapy.