Incomplete androgen insensitivity syndrome: partially masculinized genitalia in two patients with absence of androgen receptor in cultured fibroblasts.

In male pseudo-hermaphroditism due to end organ unresponsiveness, partial androgen insensitivity can usually be related to low but detectable dihydrotestosterone (DHT) binding activity in cultured sexual skin fibroblasts. We have studied two patients with partial virilization and total absence of androgen receptors in cultured fibroblasts. A lack of DHT binding could be related to a selection of a fibroblast strain with no androgen receptor activity, to insufficient sensitivity of the method in detecting very low receptor concentrations or to an instability of the receptor or the androgen-receptor complex. However, these observations raise the question of masculinization of external genitalia with undetectable androgen receptor.