an excess of
lipoproteins in the blood, due to a disorder of lipoprotein metabolism; it may be acquired or hereditary. The
acquired form occurs secondary to another disorder or as a result of environmental factors such as diet. The
hereditary form is classified into five major phenotypes based on clinical features, enzymatic abnormalities, and serum lipoprotein electrophoretic patterns:
Type I may be manifested clinically by repeated bouts of abdominal pain and vomiting, recurrent acute pancreatitis, eruptive xanthomas, hepatosplenomegaly, and lipemia retinalis.
Type II (called also
familial hypercholesterolemia) is an autosomal dominant condition characterized by tendinous and tuberous
xanthomas,
xanthelasmas, early onset of corneal arcus, and accelerated atherosclerosis; children homozygous for the defect may have coronary artery disease and
myocardial infarctions in childhood.
Type III is characterized chiefly by planar
xanthomas and is related to
familial dysbetalipoproteinemia.
Type IV is marked by mild
hypertriglyceridemia and is related to
tangier disease and is marked by increased incidence of vascular disease, abnormal glucose tolerance, and family history of
diabetes mellitus.
Type V is characterized by severe
hypertriglyceridemia and may include
diabetes mellitus, eruptive
xanthomas, and recurrent acute
pancreatitis.