A Case of Female Pseudohermaphroditism Caused by Aromatase Deficiency

Female pseudohermaphroditism is caused by several etiologies. Here we report acase of aromatase deficiency who showed ambiguous genitalia and maternal virilizationduring pregnancy. The mother had noticed her own virilization from 16 wk of gestationwithout androgen exposure and had low urinary estriol levels (5~10 μg/mlat 35 wk of gestation). At birth, the patient presented severe virilization (Prader V),and was assigned as a male with a micropenis and unpalpable testes but the patient had anormal female karyotype and a uterus and cystic ovaries found by magnetic resonanceimaging. The patient had a increase in serum 17α-hydroxy progesterone levels (basal 4.9 →37 ng/ml after a single 0.25 mg/m² infusion of ACTH), but the increase inadrenal androgen was not sufficient to virilize the external genitalia.Dehydroepiandrosterone, 17α-hydroxy pregnenolone and deoxycorticosterone were within thenormal ranges. These findings suggested a diagnosis of nonadrenal femalepseudohermaphroditism. From the clinical features and biochemical data, weendocrinologically diagnosed her as having an aromatase deficiency. The aromatase gene isnow under investigation for definite diagnosis. We finally agreed that aromatasedeficiency should be suspected when both the mother and the newborn have beenvirilized.