Inborn errors of steroid metabolism

Inborn error of steroid metabolism
Steroidogenesis
Specialty	Medical genetics, endocrinology

An inborn error of steroid metabolism is an inborn error of metabolism due to defects in steroid metabolism.^{[citation needed]}

A variety of conditions of abnormal steroidogenesis exist due to genetic mutations in the steroidogenic enzymes involved in the process, of which include:

• 20,22-Desmolase (P450scc) deficiency: blocks production of all steroid hormones from cholesterol ^{[citation needed]}
• 3β-Hydroxysteroid dehydrogenase 2 deficiency: impairs progestogen and androgen metabolism; prevents the synthesis of estrogens, glucocorticoids, and mineralocorticoids; causes androgen deficiency in males and androgen excess in females^{[citation needed]}
• Combined 17α-hydroxylase/17,20-lyase deficiency: impairs progestogen metabolism; prevents androgen, estrogen, and glucocorticoid synthesis; causes mineralocorticoid excess^{[citation needed]}
• Cytochrome P450 oxidoreductase deficiency: prevents production of numerous but not all sex steroids,^[1] as well as other metabolic reactions

• Isolated 17,20-lyase deficiency: prevents androgen and estrogen synthesis.^[2]
  • Cytochrome b₅ deficiency: subtype of isolated 17,20-lyase deficiency; additionally results in elevated methemoglobin and/or methemoglobinemia
• 17β-Hydroxysteroid dehydrogenase 3 deficiency: impairs androgen and estrogen metabolism; results in androgen deficiency in males and androgen excess and estrogen deficiency in females^{[citation needed]}
• 5α-Reductase 2 deficiency: prevents the conversion of testosterone to dihydrotestosterone; causes androgen deficiency in males^{[citation needed]}
• Aromatase deficiency: prevents estrogen synthesis; causes androgen excess in females^{[citation needed]}
• Aromatase excess: causes excessive conversion of androgens to estrogens; results in estrogen excess in both sexes and androgen deficiency in males.^{[citation needed]}

• 21-Hydroxylase deficiency: prevents glucocorticoid and mineralocorticoid synthesis; causes androgen excess in females^{[citation needed]}
• 11β-Hydroxylase 1 deficiency: impairs glucocorticoid and mineralocorticoid metabolism; causes glucocorticoid deficiency and mineralocorticoid excess as well as androgen excess in females^{[citation needed]}
• 11β-Hydroxylase 2 deficiency: impairs corticosteroid metabolism; results in excessive mineralocorticoid activity^{[citation needed]}
• 18-Hydroxylase deficiency: prevents mineralocorticoid synthesis; results in mineralocorticoid deficiency^{[citation needed]}
• 18-Hydroxylase overactivity: impairs mineralocorticoid metabolism; results in mineralocorticoid excess^{[citation needed]}

In addition, several conditions of abnormal steroidogenesis due to genetic mutations in receptors, as opposed to enzymes, also exist, including:^{[citation needed]}

• Gonadotropin-releasing hormone (GnRH) insensitivity: prevents synthesis of sex steroids by the gonads in both sexes
• Follicle-stimulating (FSH) hormone insensitivity: prevents synthesis of sex steroids by the gonads in females; merely causes problems with fertility in males
• Luteinizing hormone (LH) insensitivity: prevents synthesis of sex steroids by the gonads in males; merely causes problems with fertility in females
• Luteinizing hormone (LH) oversensitivity: causes androgen excess in males, resulting in precocious puberty; females are asymptomatic

No activating mutations of the GnRH receptor in humans have been described in the medical literature,^[3] and only one of the FSH receptor has been described, which presented as asymptomatic.^[4][5]

• Miller WL, Auchus RJ (February 2011). "The molecular biology, biochemistry, and physiology of human steroidogenesis and its disorders". Endocrine Reviews. 32 (1): 81–151. doi:10.1210/er.2010-0013. PMC 3365799. PMID 21051590.^{[permanent dead link‍]}