What is familial hypobetalipoproteinemia (FHBL)?

Updated: Mar 06, 2018
  • Author: Vibhuti N Singh, MD, MPH, FACC, FSCAI; Chief Editor: George T Griffing, MD  more...
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FHBL is also a rare disorder of apolipoprotein B (apoB) metabolism characterized by levels of plasma cholesterol and LDL cholesterol that are less than one-half normal in heterozygotes and are very low (< 50 mg/dL) in homozygotes. FHBL is caused by an autosomal, codominant mutation in the gene for apoB (APOB), which is carried on chromosome 2. This mutation results in a truncated form of apoB. [4, 5]  Homozygotes present with fat malabsorption and low plasma cholesterol levels at a young age. They develop progressive neurologic degenerative disease, retinitis pigmentosa, and acanthocytosis, similar to patients with ABL. Although heterozygotes are usually asymptomatic, they exhibit decreased LDL cholesterol and apoB levels and possibly have a decreased risk of atherosclerosis. [6, 7, 8]

The nonfamilial forms of hypobetalipoproteinemia are secondary to a number of clinical states, such as occult malignancy, malnutrition, and chronic liver disease.

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