[17 beta-hydroxysteroid dehydrogenase defect: female phenotype with 46,XY karyotype]

Deficiency of the 17 beta-hydroxysteroid dehydrogenase (17b-HSD-d) causes female external genital phenotype in spite of 46,XY karyotype and presence of testes due to disorder in biosynthesis of testosterone. However, marked somatic and genital virilization occurs during puberty. Clinical and laboratory investigation of three cases are presented with typical elevation of the precursor steroid androstenedione, and decrease of product steroid testosterone. All the three patients were reared as girls. During puberty orchidectomy was performed in two cases and vaginoplasty in one case. Estrogen replacement therapy contributed to development of female secondary sex characteristics.