Endocrine and genetic characterization of cousins with male pseudohermaphroditism: evidence that the Lubs pheno‐type can result from a mutation that alters the structure of the androgen receptor

Impaired virilization of genetic males with testes (male pseudohermaphroditism) can result either from deficiency in androgen production or defects in androgen action, the latter most commonly involving an abnormal androgen receptor. We report here two maternal cousins with male pseudohermaphroditism and clinical features characteristic of the Lubs phenotype, namely apparent females with sufficient fusion of the labioscrotal folds so that a single urogenital sinus orifice is present. Testosterone levels in these genetic males rose appropriately after administration of human chorionic gonadotropin. The amount (maximal binding capacity of 24 to 30 fmol/mg protein) and hormone binding affinity (half‐maximal saturation of 0.2 nM) of the androgen receptor in cultured skin fibroblasts was normal, but the receptor was qualitatively abnormal as evidenced by instability on sucrose density gradient centrifugation. The pattern of inheritance in this family is compatible with X‐linkage. These findings, together with previous studies, indicate that the spectrum of abnormalities that result from defects of the androgen receptor in genetic men can encompass the entire spectrum between male and female phenotypes.