The CYP11A1 (SCC) gene encodes the cholesterol side-chain cleavage enzyme (P450scc), which is a member of the cytochrome P450 superfamily of enzymes.  The cytochrome P450 proteins function as a monooxygenase in the mitochondrion that catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids.  P450scc enzyme catalyzes the conversion of cholesterol to pregnenolone, the first and rate-limiting step in the synthesis of all steroids.  This CYP11A1 gene is expressed only in steroidogenic organs such as the adrenal, gonads, placenta, and brain.  Its expression follows a developmentally programmed, cell type-specific and hormonally regulated pattern.  Defects in this enzyme are the cause of congenital adrenal insufficiency with 46,XY sex reversal (AICSR).

The CYP11A1 gene, which codes for a cholesterol side-chain cleavage enzyme, is located on the long arm of chromosome 15, and is about 30 kb long with its nine coding exons.  It has two transcript variants encoding different isoforms.  Mutations in this gene have been associated with congenital adrenal insufficiency with 46,XY sex reversal (AICSR) and pathogenesis of polycystic ovary syndrome.