Cells from individuals with Wolman disease or Cholesteryl Ester Storage disease revealed how lysosomal acid lipase converts cholesteryl esters liberated from the endocytosed LDL to unesterified cholesterol, a form that can be used by cells (Brown et al., 1976; Goldstein et al., 1975; Sloan and Fredrickson, 1972; Wolman et al., 1961). The gene discussed is LIPA; the disease is Wolman disease.