{"type":"root","children":[{"type":"paragraph","children":[{"type":"text","value":"Steroidogenic acute regulatory protein (STAR) is a protein that in humans is encoded by the STAR gene. STAR plays a key role in the acute regulation of steroid hormone synthesis by enhancing the conversion of cholesterol into pregnenolone. This protein permits the cleavage of cholesterol into pregnenolone by mediating the transport of cholesterol from the outer mitochondrial membrane to the inner mitochondrial membrane STAR is primarily present in steroid-producing cells, including Leydig cells in the testis, theca cells and luteal cells in the ovary and adrenal cells in the adrenal cortex. Low levels of STAR expression in other tissues that produce steroid hormones for local use have been reported. Mutations in the STAR gene are a cause of congenital lipoid adrenal hyperplasia, also called lipoid CAH."}]}]}