A disorder of lipid metabolism in which massively elevated levels of triglycerides are accompanied by the presence of chylomicrons in the blood, even after a fast. It results in abdominal pain, eruptive xanthomas, hepatosplenomegaly, memory loss, and occasionally, life-threatening pancreatitis. The syndrome may result from congenital deficiencies or inhibition of lipoprotein lipase; from apolipoprotein deficiency; or from diseases or conditions that elevate plasma triglyceride levels (poorly controlled diabetes mellitus; excessive ingestion of alcohol; the use of some drugs).