Mutations in the SRD5A2 gene can result in a 46,XY disorder of sex development (46,XY DSD) called<unk>  <unk> R2D). The mutations are inherited in an autosomal recessive pattern can be either homozygous or, less frequently, compound heterozygous loss-of-function. Affected males exhibit a broad spectrum of presentation including atypical genitalia (ranging from female appearing to undervirilized male), hypospadias, penile urethra, and isolated micropenis. The internal reproductive structures (vasa deferentia, seminal vesicles, epididymides and ejaculatory ducts) are normal but testes are usually undescended and prostate hypoplasia is common. Males with the same mutations in SRD5A2 can have different phenotypes suggesting additional factors that are involved in clinical presentation. Females with the same mutations in SRD5A2 as affected males (as seen in siblings) are unaffected and have normal female phenotypes and reproductive function. Virilization of genitalia with voice deepening, development of muscle mass occur at puberty in affected males and height is not impaired. Gynecomastia is uncommon and bone density is normal in contrast to 46,XY DSD from other causes such as partial androgen insensitivity syndrome and 17β-hydroxysteroid dehydrogenase 3<unk> . Hair on the face and body is reduced though male pattern baldness does not occur.
5α-Reductase 2 deficiency
Isolated 17,20-lyase deficiency
17β-Hydroxysteroid dehydrogenase III deficiency
Aromatase deficiency
Cortisone reductase deficiency
Androgen-induced hermaphroditism
Multiple sulfatase deficiency
Gonadotropin-releasing hormone insensitivity