Lipoproteins are aggregates of proteins and lipids that facilitate the circulation of hydrophobic lipids in the body.<unk>  of lipids and lipoproteins metabolism have important health consequences, primarily on the cardiovascular system; however, may also affect the cerebrovascular system as well as the gastrointestinal system.<unk>  can be described as abnormalities in the level of the lipids, which include cholesterol and triglycerides, or as abnormalities in the levels of lipoproteins that include LDL, HDL, VLDL and chylomicrons.<unk>  (also referred to as Lipid<unk> , or Dyslipidemias, or Dyslipoproteinemias) were first classified in 1967 into different phenotypes by Fredrickson according to the type of lipoproteins that are affected. This approach is considered outdated for a number of reasons. Firstly, Friedrickson's classification failed to classify<unk>  of low lipids. Secondly, Fredrickson's classification of hyperlipoproteinemias took into consideration the elevation in chylomicrons, LDL, VLDL but did not include abnormalities in HDL levels. Other classifications have been suggested, one of which is the National Cholesterol Education Program (NCEP) classification of<unk> . NCEP classifies lipid<unk>  according to laboratory cut off points for the levels of total cholesterol, LDL-C and HDL.<unk>  must be initially classified broadly into hypolipidemias and hyperlipidemias corresponding to low or high lipid levels, respectively. Each of these broad categories may be further classified into primary (genetic) causes or secondary environmental causes (e.g. substance abuse, medication use, lifestyle habits, or underlying diseases, etc.). Secondary causes of lipid<unk>  are more common and thus must be ruled out before exploring the primary causes of dyslipidemia.
Primary dyslipidemias are generally consistent in the way they affect the lipoproteins. Hyperlipoproteinemias generally cause elevations in the affected lipids/lipoproteins and hypolipoproteinemias generally cause reductions in the affected lipids/lipoproteins. Secondary dyslipidemias, on the other hand, may cause elevations in some lipoproteins and reductions in others. An example of this is the lipid profile in patients with diabetes mellitus, which commonly reveals a dyslipidemic triad consisting of elevated LDL and triglycerides with a concurrent reduction in HDL. In this case, diabetes mellitus and metabolic syndrome would be widely considered a hyperlipidemic disease due to the array of cardiovascular and cerebrovascular sequelae that arise consequent to the chronic hyperlipidemia associated with the disease. This is to say that in cases of mixed (elevated and decreased) findings on the lipid profile, clinicians must evaluate the secondary causes of the dysipidemia and manage the affected lipoproteins accordingly.
Lipoprotein disorders
Endocrine diseases
Hyperlipoproteinemia laboratory findings
Sickle-cell disease causes
Dermatological lesions
Gaucher's disease risk factors
VLDL hyperlipidemia
Cancer risk factors