Figure 2.

Proposed urine steroid metabolite ratios for a prenatal diagnosis of PORD. Illustrated are normative values from gestational week 15 to week 23 (n = 60) and 4 pregnancies with affected PORD babies and 1 pregnancy with a heterozygous carrier. Panel A shows reduced estriol relative to the excretion of the progesterone metabolite PD. Panel B shows increased value of the EpialloPD to estriol ratio resulting from pregnenolone accumulation caused by attenuated 17-hydroxylase/17,20-lyase and decreased estriol production. Panel C shows increased 16-hydroxyandrosterone excretion in relation to decreased estriol, indicative of the effect of mutant POR on CYP19A1 aromatase activity. Panel D shows increased androsterone excretion compared with etiocholanolone, indicative of alternative pathway androgen synthesis activity (2). Panel E gives the abbreviation and systematic name of the urinary steroid metabolites and from which they derive. The ratios denoted by an asterisk were obtained from a previously published report on a patient (17).