A mutation (A82T) is described in the coding sequence of the gene for 3ß-hydroxysteroid dehydrogenase (3ß-HSD) type II that is associated with variable clinical consequences. Four homozygotes are described, all of which showed elevated levels of Δ5 steroids consistent with 3ß-HSD deficiency. Two males from a consanguineous family were found to be homozygous for A82T and were affected with pseudohermaphroditism. They differed in their degree of mild salt loss. In the same family a female was found to be homozygous for A82T, but was clinically normal and had no history of premature pubarche or of abnormal menstrual cycles. However, in an apparently unrelated family, the A82T mutation was found in a female affected with premature pubarche. This is the first report of a proven mutation in 3ß-HSD type II associated with premature pubarche.