Aromatase Deficiency

Aromatase deficiency is a rare disorder resulting in estrogen insufficiency in males and females. The first indication is often transient maternal virilization during pregnancy, which has been reported in mothers of affected males and females. The degree of maternal virilization is variable, but common features include a deepening voice, acne, hirsuitism, and/or clitoromegaly . 46,XX females with aromatase deficiency present at birth with ambiguous genitalia typically consisting of labioscrotal fusion, an enlarged phallus with a urogenital sinus, and the presence of a vagina and uterus. At puberty, affected females exhibit primary amenorrhea, failure of breast development, hypergonadotropic hypogonadism, and cystic ovaries. Treatment with exogenous estrogen results in normal skeletal maturation and the development of secondary female sexual characteristics. The phenotype of 46,XY males with aromatase deficiency is variable, but common features include tall stature with delayed closure of the epiphyses, osteoporosis, eunuchoid body habitus, abdominal adiposity, gynecomastia, and progressive genu valgum. Biochemical studies reveal undetectable estrogen levels and normal to elevated testosterone and gonadotropins. Metabolic syndrome resulting in hyperinsulinism, acanthosis nigricans, and nonalcoholic fatty liver disease has also been reported. Fertility is likely impaired, although only a limited number of patients have been evaluated. Estrogen replacement therapy results in improved bone mineral density, closure of the epiphyses, and normalization of insulin levels.