Steroid 21-hydroxylase

Oxidoreductase localized in the cells of the adrenal cortex, which is essential for the biosynthesis of the steroid hormones aldosterone and cortisol. The key enzyme steroid-21-hydroxylase catalyzes the oxidation of the C21 carbon molecule in the steroid molecule (conversion of 17-OH-progesterone or progesterone to 11-deoxycortisol), a step that is essential for the structural design of the molecular structure of these steroid hormones.

The reason for the mutation of the gene lies in a recombination step with an inactive pseudogen located on the same chromosome section, which is necessary for the formation of these hormones.

Autoantibodies against steroid 21-hydroxylase lead to autoimmune adrenalitis and destruction of the adrenal cortex. They are the cause of primary adrenal insufficiency(Addison's disease - E27.1-). Furthermore, autoantibodies against this oxyreductase are found in polyglandular autoimmune syndromes (E31.0).

1. Bansal S et al (2015) Presence of 21-hydroxylase Antibodies in a Boy with X-Linked Adrenal HypoplasiaCongenita
   . Horm Res Paediatr 84:408-413.
2. Dörr HG et al. (2018) Mortality in children with classic congenital adrenal hyperplasia and 21-hydroxylase deficiency (CAH) in Germany. BMC Endocr Disord 18:37.