Third, the most compelling evidence for a role of StAR in steroiodogenesis was provided by demonstrating that mutations in the StAR gene cause a fatal condition in newborns, the congenital lipoid adrenal hyperplasia (lipoid CAH), characterized by severe impairment of steroiodogenesis, hypertrophied adrenals containing high levels of cholesterol esters and free cholesterol and increased amounts of neutral lipids in the testicular Leydig cells [276,278]. This evidence concerns the gene STAR and congenital lipoid adrenal hyperplasia due to STAR deficency.