Aromatase deficiency

Aromatase deficiency is a rare condition in which the enzyme aromatase, which makes estrogens from androgens, is extremely low or absent. It is an autosomal recessive disorder caused by various mutations of the CYP19 gene. In females it can cause ambiguous genitalia at birth, with the internal female organs normal, followed by delayed puberty, absent breast development, primary amenorrhea, tall stature and polycystic ovaries. In males it usually shows in adulthood as tall stature, osteopenia or osteoporosis, type 2 diabetes and disordered lipid metabolism. A fetus with the condition can also virilize its mother during pregnancy, because the placenta cannot convert androgens to estrogens, and her symptoms normally fade after delivery. Fewer than 15 genetically male and at least 30 genetically female cases had been identified by 2020.