17-beta-hydroxysteroid dehydrogenase 3 deficiency overview

17-beta-hydroxysteroid dehydrogenase deficiency is a rare autososmal recessive developmental disorder that affects male sexual development. The synthesis of testestrone is impaired and the levels in the serum is low which disrupts the formation of external male genitalia before birth. The affected individual is genetically male with XY chromosomes with phenotype female or ambigiounal external genitalia, characterized by clitoromegaly, posterior labioscrotal fusion and perineal blind vaginal pouch. Testes are located in inguinal or in the labioscrotal folds. The internal urogenital tract (epididymides, vasa deferentia, seminal vesicles, ejaculatory ducts) is well developed; prostate and Müllerian structures are absent. Although some patients with less severe defects are brought up as males, affected males are usually raised as girls. During puberty, most of the affected individuals develop male secondary sex characteristics, such as increased muscle mass, deepening of the voice, and development of male pattern body hair. All affected people with the disease are infertile.