A girl presented with small stature, obesity, tapetoretinal degeneration, deafness, psychomotor regression, seizures, acanthosis nigricans, hepatomegaly, and chronic tubulointerstitial nephropathy. She died at age ten with renal insufficiency and uncontrolled seizures. Histochemistry showed lipid storage in hepatocytes, histiocytes, smooth muscles and, to a much lesser extent, kidney tubules and cortical neurons. The liver had increased cholesterol esters (5-fold) and triacylglycerols (8-fold), and decreased phospholipids (50%). Methyllumbelliferyl-oleate, oleylcholestrol, trioleylglycerol, and tripalmitylglycerol lipase activities were markedly reduced in the liver, in the range found in Wolman's disease. In cirrhotic fatty livers these activities ranged from 7-87% of the normal mean. The patient's brain had limited neutral lipid storage and normal methyllumbelliferyl-oleate lipase. Trioleylglycerol lipase activity was 14-60% of controls; tripalmitylglycerol lipase activity 14-25% of controls; and oleylcholestrol lipase activity 12-33% of controls.