Familial male pseudohermaphroditism with gynaecomastia due to 17 beta-hydroxysteroid dehydrogenase deficiency. A report of 3 cases.

Three sisters with male pseudohermaphroditism due to 17 beta-hydroxysteroid dehydrogenase deficiency are described. On the basis of a 46 XY karyotype and female phenotype all subjects were thought to have the testicular feminization syndrome. At puberty the two older patients developed signs of virilization and gynaecomastia. In these patients the plasma androstenedione level was 4-5 times higher than normal, whilst the plasma testosterone level was low compared to the normal range and, under basal conditions, their plasma androstenedione to testosterone ratio was 20-25 times higher than normal. Interestingly, in the third, prepubertal case, the basal androstenedione to testosterone ratio was normal but became six times higher than normal after hCG stimulation. These data support the diagnosis of male pseudohermaphroditism due to 17 beta-hydroxysteroid dehydrogenase deficiency and underline the diagnostic value of the hCG stimulation test prepubertally.