Читать книгу Handbook of Clinical Gender Medicine - Группа авторов - Страница 65

Genital masculinization in a chromosomally normal (XX) female infant, consisting of clitoromegaly and various degrees of vaginal abnormality, may result from congenital adrenal hyperplasia (CAH). This DSD has a prevalence of 1 in 15,000 births worldwide and is associated with a deficiency in 21-hydroxylase. Consequent virilization occurs because the external genitalia are competent to respond to DHT. The milder enzyme deficiency, i.e. nonclassical 21-hydroxylase deficiency (NC21OHD), was found to be the most common autosomal recessive disorder in humans. The disease frequency of NC21OHD varies between ethnic groups, with the highest ethnic-specific disease frequency in Ashkenazi Jews (1 in 27). NC21OHD is diagnosed based on serum elevations of 17-OHP and confirmed with molecular genetic analysis. Females with ‘classical’ 21 - OHD are exposed to excess androgens prenatally and are born with virilized external genitalia. Potentially lethal adrenal insufficiency is characteristic of two thirds to three quarters of patients with the classical salt-wasting form of 21-OHD. Non-salt-wasting 21-OHD may be diagnosed based on genital ambiguity in affected females, and/or later on the occurrence of androgen excess in both sexes. Another CAH variant, p450 oxidoreductase deficiency may also result in ambiguous genitalia [4–7].