A description is presented of the first documented case of placental
aromatase deficiency. The deficiency caused maternal
virilization during pregnancy and
pseudohermaphroditism of the female fetus. A 24-yr-old primigravida showed progressive
virilization during the third trimester. Urinary excretion of
estrogen was less than 14 mumol/day between 35-38 weeks of pregnancy, although nonstress tests showed reactive patterns and serum levels of
human placental lactogen were above 460 nmol/L. Maternal serum levels of
estrogens were low, and those of
androgens were high in the third trimester. A
dehydroepiandrosterone sulfate loading test induced a marked increase in maternal serum levels of
androgens, whereas no such increase was observed in
estrogens. The woman delivered vaginally a live full-term infant who exhibited
female pseudohermaphroditism. Cord serum levels of
estrogens were extremely low, while those of
androgens were high. The
aromatase activity of the placenta, determined by the conversion of [7-3H]
androstenedione to 17 beta-[7-3H]
estradiol and [7-3H]
estrone, were less than 0.03 fmol/microgram
protein.min (control, 9.6 +/- 2.2 fmol/microgram
protein.min). The
sulfatase activity of the placenta was 0.63 pmol/microgram
protein.min compared to 0.46 +/- 0.16 pmol/microgram
protein.min in controls. The rate of aromatization by normal control placentas was the same as that obtained during coincubation of samples of normal placentas and that of the patient. Thus, the presence of
aromatase inhibitor in the patient's placenta was excluded.