Mutation THR-185 ILE is associated with corticosterone methyl oxidase deficiency type II.
Two boys presenting with infection-triggered, life-threatening salt-loss and hyperkalaemia were published in 1991 in the European Journal of Pediatrics. In both boys, the diagnosis of corticosterone methyl oxidase (CMO) deficiency type II has been established on the basis of determinations of plasma and urinary steroids. We had the opportunity to perform a molecular genetic study in one of the two boys. This boy had an elevated plasma 18-hydroxycorticosterone/aldosterone ratio which is pathognomonic for CMO deficiency type II. Sequence analysis of the CYP11B2 gene revealed a homozygous single base exchange in codon 185 of CYP11B2 causing an amino acid substitution Thr185Ile.


CONCLUSIONS
A Thr185Ile mutation in the CYP11B2 gene was found in a patient with CMO deficiency type II. This mutation may change the secondary structure of the enzyme leading to its decreased activity.
Peter
M
M
Department of Paediatrics, Christian-Albrechts-University of Kiel, Germany. m.peter@pediatrics.uni-kiel.de
Bünger
K
K
Sólyom
J
J
Sippell
W G
WG
D019943:Amino Acid Substitution; D019405:Cytochrome P-450 CYP11B2 / Q000235:genetics*; D006801:Humans; D006994:Hypoaldosteronism / Q000151:congenital* / Q000235:genetics*; D007223:Infant; D008297:Male; D008661:Metabolism, Inborn Errors / Q000235:genetics*; D006899:Mixed Function Oxygenases / Q000172:deficiency*; D009154:Mutation
D006899:Mixed Function Oxygenases; D019405:Cytochrome P-450 CYP11B2; C025352:corticosterone methyl oxidase II