Defects of cholesterol biosynthesis.

Eight distinct inherited disorders have been linked to different enzyme defects in the isoprenoid/cholesterol biosynthetic pathway following the finding of abnormally increased levels of intermediate metabolites in patients and confirmed by the demonstration of disease-causing mutations in genes encoding the implicated enzymes. Patients afflicted with these disorders are characterized by multiple morphogenic and congenital anomalies including internal organ, skeletal and/or skin abnormalities underlining an important role for cholesterol in human embryogenesis and development. The etiology of the underlying pathophysiology may involve multiple affected processes due to lowered cholesterol and/or the elevated, teratogenic levels of the intermediate sterol precursors.