Lipoprotein disorders causes

Lipoprotein Disorders Microchapters
Patient Information
Overview
Causes
Classification Hyperlipoproteinemia Hypolipoproteinemia
Treatment

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

Hyperlipidemia can occur as either a primary event or secondary to some underlying disease. The primary hyperlipidemias include chylomicronemia, hypercholesterolemia, dysbetalipoproteinemia, hypertriglyceridemia, mixed hyperlipoproteinemia, and combined hyperlipoproteinemia. Other diseases, such as diabetes mellitus, pancreatitis, renal disease, and hypothyroidism, can cause the secondary form.

Causes

Primary hyperlipidemia

Hyperlipoproteinemia type I

• Deficiency of lipoprotein lipase (LPL) or altered apolipoprotein C2

Hyperlipoproteinemia type II

Type IIa

• Familial hypercholesterolemia
  • Sporadic (due to dietary factors)
  • Polygenic
  • Truly familial (as a result of a mutation in the LDL receptor gene on chromosome 19 (0.2% of the population), the ApoB gene (0.2%) or the proprotein convertase subtilisin kexin 9 (PCSK9) gene (very rare))

Type IIb

• Familial combined hyperlipoproteinemia (FCH)
  • Overproduction of hepatically-derived apo B-100 associated with VLDL
  • Overproduction of substrates, including triglycerides and acetyl-CoA
  • Decreased clearance of LDL

• Secondary combined hyperlipoproteinemia (usually in the context of metabolic syndrome)

Hyperlipoproteinemia type III

This form is due to high chylomicrons and IDL (intermediate density lipoprotein). Also known as broad beta disease or dysbetalipoproteinemia, the most common cause for this form is the presence of ApoE E2/E2 genotype. It is due to cholesterol-rich VLDL (β-VLDL). Prevalence is 0.02% of the population.

Hyperlipoproteinemia type IV

This form is due to high triglycerides. It is also known as hypertriglyceridemia (or pure hypertriglyceridemia). According to the NCEP-ATPIII definition of high triglycerides (>200 mg/dl), prevalence is about 16% of adult population.

Hyperlipoproteinemia type V

This type is very similar to type I, but with high VLDL in addition to chylomicrons. It is also associated with glucose intolerance and hyperuricemia.