17β-hydroxysteroid dehydrogenase-3 deficiency: Genetics, clinical findings, diagnosis and molecular biology

17β-hydroxisteroid-dehydrogenase deficiency is a rare autosomal recessive form of male pseudohermaphroditism, due to mutations in the 17β-hydroxisteroid-dehydrogenase type 3 gene. Mutated genes encode an abnormal enzyme with absent or reduced ability to convert Δ ⁴-androstenedione to testosterone in the testis. Affected individuals are genetically males with normal male Wolffian structures, but have female external genitalia. These individuals are usually raised as females but undergo spontaneous virilization at puberty. Thus, correct diagnosis is mandatory to optimize treatment and follow-up. The clinical and laboratory approach as well as the follow-up of patients with male pseudohermaphroditism due to 17β-hydroxisteroid-dehydrogenase deficiency are detailed. The genetic mutations characterized to date are also summarized.