[Prenatal diagnosis in a familial form of male pseudohermaphroditism due to 17-keto reductase deficiency].

In an infant considered at birth as a female but with easily palpable gonads in the labia major, the XY karyotype and the endocrine studies (determination of plasma levels of steroid hormones under basal conditions and during hCG stimulation) were consistent with the diagnosis of male pseudohermaphroditism due to 17-keto reductase deficiency. During the second pregnancy an amniocentesis revealed a 46 XY karyotype. Endocrine studies performed on the amniotic fluid at midgestation suggested that the fetus was affected by the same enzyme defect. After birth, the diagnosis was demonstrated with anatomical an endocrine studies.