Urine Steroid Hormone Profile Analysis in Cytochrome P450 Oxidoreductase Deficiency: Implication for the Backdoor Pathway to Dihydrotestosterone

reflecting CYP17A1 and CYP21A2 activities were decreased throughout the examined ages. Furthermore, etiocholanolone and 11-hydroxyandrosterone, which should originate almost exclusively from androstenedione in the conventional “frontdoor” pathway, were grossly normal or somewhat decreased since early infancy, whereas androsterone, which can be derived not only from androstenedione and dihydrotestosterone in the conventional frontdoor pathway but also from 5-pregnane-3,17-diol-20-one in the backdoor pathway, was increased during early infancy and remained grossly normal thereafter. Thus, the androsterone to etiocholanolone ratio was increased during early infancy and remained grossly normal thereafter. 5-Pregnane-3,17-diol-20-one was elevated throughout the examined ages. Conclusions: The increased androsterone excretion during early infancy, as compared with the etiocholanolone and 11-hydroxyandrosterone excretions in the same period, suggests the presence of the backdoor pathway in PORD. (J Clin Endocrinol Metab 91: 2643–2649, 2006)