Biochemical selection of prepubertal patients with androgen insensitivity syndrome by sex hormone-binding globulin response to the human chorionic gonadotropin test

Before puberty, the diagnosis of androgen insensitivity syndrome (AIS) can be difficult. We studied whether the decrease of sex hormone-binding globulin (SHBG) during the human chorionic gonadotropin (hCG) test may represent a biochemical test to select prepubertal patients with AIS. We examined prepubertal patients with AIS (n = 9, age 0.9-8.2 y), male pseudohermaphroditism not due to AIS (other-MPH) (n = 8, age 0.6-10.7 y), and control boys (n = 12, age 0.8-12.5 y). Testosterone and SHBG levels (mean +/- SD) were measured before (d 0) and after (d 5) a hCG test (1500 IU X 3 d). Testosterone levels (nmol/L) increased in all groups [AIS: from 1.5 +/- 1.2 to 22.1 +/- 11.8 (p < 0.001); other-MPH: from 0.6 +/- 0.6 to 9.2 +/- 7.4 (p < 0.02); controls: from 1.8 +/- 1.4 to 22.8 +/- 14.4 (p < 0.001)]. SHBG concentrations (nmol/L) did not change in AIS [from 66.2 +/- 15.1 to 67.5 +/- 18.6 (p = NS), delta-variation 1.7 +/- 12.7%], whereas they were significantly decreased in other-MPH [from 59.9 +/- 14.2 to 46.5 +/- 18.6 (p < 0.005), delta-variation -23.7 +/- 19.6%] and controls [from 63.0 +/- 16.9 to 33.7 +/- 14.6 (p < 0.003), delta-variation -46.9 +/- 15.2%]. Our data suggest that the SHBG changes during the hCG test can be used to assess in vivo the biologic response to androgens in prepubertal patients with ambiguous genitalia, selecting those patients in whom it is worth performing second level investigations to confirm the AIS diagnosis.