title: Steroid 5 alpha-reductase 2 deficiency.
abstract: In the 20 yr since it was established that impairment of dihydrotestosterone formation is the cause of a rare form of human intersex, a wealth of information has accumulated about the genetics, endocrinology, and variable phenotypic manifestations, culminating in the cloning of cDNAs encoding two 5 alpha-reductase genes and documentation that mutations in the steroid 5 alpha-reductase 2 gene are the cause of 5 alpha-reductase deficiency. Perplexing and difficult problems remain unresolved, e.g. whether the variability in manifestations is due to variable expressions of steroid 5 alpha-reductase 1 or to effects of testosterone itself. It is also imperative to establish whether defects in steroid 5 alpha-reductase 2, perhaps in the heterozygous state, are responsible for a portion of cases of sporadic hypospadias, to determine whether 5 alpha-reductase plays a role in progesterone action in women, and to elucidate the relation between androgen action and gender role behavior.
authors.affiliation: Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas 75235.
authors.forename: J D
authors.initials: JD
authors.lastname: Wilson
authors.forename: J E
authors.initials: JE
authors.lastname: Griffin
authors.forename: D W
authors.initials: DW
authors.lastname: Russell
mesh_terms: D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism; D000728:Androgens / Q000494:pharmacology / Q000502:physiology; D013196:Dihydrotestosterone / Q000378:metabolism; D012734:Disorders of Sex Development / Q000201:enzymology / Q000235:genetics; D004967:Estrogens / Q000502:physiology; D005260:Female; D005783:Gender Identity; D006801:Humans; D008297:Male; D010641:Phenotype; D012733:Sex Differentiation
chemical_list: D000728:Androgens; D004967:Estrogens; D013196:Dihydrotestosterone; D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase