Hyperlipoproteinemias: Part I. Lipoprotein classification and abnormalities.

The hyperlipoproteinemias are disturbances in the metabolism of lipoproteins. Elevated levels of total and low density lipoprotein-cholesterol, and low levels of high density lipoprotein-cholesterol are proven risk factors for atherosclerosis. The significance of hypertriglyceridemia as an independent risk factor for atherosclerosis is controversial, however, at high levels triglycerides are a major risk factor for pancreatitis. Lipoprotein abnormalities can be divided into dietary, primary (genetic), and secondary disorders. The major causes of moderate and severe hypercholesterolemia are familial hypercholesterolemia, familial combined hyperlipidemia, severe primary (polygenic) hypercholesterolemia, and familial dysbetalipoproteinemia. Causes of hypertriglyceridemia include familial hypertriglyceridemia, familial lipoprotein lipase deficiency, sporadic hypertriglyceridemia, and secondary causes.