Inborn errors of steroid metabolism

• 20,22-Desmolase (P450scc) deficiency: blocks production of all steroid hormones from cholesterol
• 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
• Combined 17α-hydroxylase/17,20-lyase deficiency: impairs progestogen metabolism; prevents androgen, estrogen, and glucocorticoid synthesis; causes mineralocorticoid excess
• 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
• 5α-Reductase 2 deficiency: prevents the conversion of testosterone to dihydrotestosterone; causes androgen deficiency in males
• Aromatase deficiency: prevents estrogen synthesis; causes androgen excess in females
• Aromatase excess: causes excessive conversion of androgens to estrogens; results in estrogen excess in both sexes and androgen deficiency in males.

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

In addition, several conditions of abnormal steroidogenesis due to genetic mutations in receptors, as opposed to enzymes, also exist, including:

• 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]