This site is intended for healthcare professionals

Go to /sign-in page

You can view 5 more pages before signing in

Familial hypobetalipoproteinaemia

Last reviewed dd mmm yyyy. Last edited dd mmm yyyy

Authoring team

  • primary hypobetalipoproteinemia (HBL) includes a group of genetic disorders:
    • abetalipoproteinemia (ABL) and chylomicron retention disease (CRD)
      • ABL and CRD both have a recessive transmission
    • familial hypobetalipoproteinemia (FHBL) with a co-dominant transmission
  • ABL and CRD are rare disorders due to mutations in the MTP and SARA2 genes, respectively
    • chylomicron retention disease (CRD)
      • absence of apoB-48-containing lipoproteins
      • affected individuals do not have chylomicrons in plasma following a fat containing meal, and have a marked accumulation of lipids in enterocytes
        • hepatic apoB synthesis is maintained and so low density lipoproteins are present in the plasma
      • clinical characteristics
        • steatorrhea, growth retardation, malnutrition, accumulation of lipid droplets in enterocytes
  • heterozygous familial hypobetalipoproteinemia (FHBL) is much more frequent than ABL or CRD
    • FHBL subjects often have fatty liver and, less frequently, intestinal fat malabsorption
    • FHBL may be linked or not to the APOB gene
      • most mutations in APOB gene cause the formation of truncated forms of apoB - these forms of apoB may or may be not secreted into the plasma
        • truncated apoBs with a size below that of apoB-30 are not detectable in plasma (more frequent in patients with the most severe phenotype)
          • heterozygotes of FHBL linked to apoB gene: asymptomatic, fatty liver, loose stools, mild fat malabsorption, gallstones
          • homozygotes/compound heterozygotes of FHBL linked to apoB gene: fatty liver, steatorrhea, acantocytosis, neurological abnormalities
          • apoB or LDL levels compared with controls - reduced < 30%
        • approximately 50% of FHBL subjects are carriers of pathogenic mutations in APOB gene
          • thus a large proportion of FHBL subjects have no apoB gene mutations or are carriers of rare amino acid substitutions in apoB with unknown effect

Reference:

  • (1) Schonfeld G. Familial hypobetalipoproteinemia: a review. J Lipid Res 2003;44: 878-883.

Create an account to add page annotations

Annotations allow you to add information to this page that would be handy to have on hand during a consultation. E.g. a website or number. This information will always show when you visit this page.

The content herein is provided for informational purposes and does not replace the need to apply professional clinical judgement when diagnosing or treating any medical condition. A licensed medical practitioner should be consulted for diagnosis and treatment of any and all medical conditions.

Connect

Copyright 2024 Oxbridge Solutions Limited, a subsidiary of OmniaMed Communications Limited. All rights reserved. Any distribution or duplication of the information contained herein is strictly prohibited. Oxbridge Solutions receives funding from advertising but maintains editorial independence.