Hypobetalipoproteinemia with an apparently recessive inheritance due to a "de novo" mutation of apolipoprotein B

Biochim Biophys Acta. 2004 Jan 20;1688(1):61-7. doi: 10.1016/j.bbadis.2003.11.002.

Abstract

Familial hypobetalipoproteinemia (FHBL) is a co-dominant disorder either linked or not linked to apolipoprotein (apo) B gene. Abetalipoproteinemia (ABL) is a recessive disorder due to mutations of microsomal triglyceride transfer protein (MTP) gene. We investigated a patient with apparently recessive hypobetalipoproteinemia consistent with symptomatic heterozygous FHBL or a "mild" form of ABL. The proband had fatty liver associated with LDL-cholesterol (LDL-C) and apo B levels <5th percentile but no truncated apo B forms detectable in plasma. MTP gene sequence revealed that he was a carrier of the I128T polymorphism and an unreported amino acid substitution (V168I) unlikely to be the cause of hypobetalipoproteinemia. Apo B gene sequence showed that he was heterozygous for two single base substitutions in exon 9 and 22 resulting in a nonsense (Q294X) and a missense (R1101H) mutation, respectively. Neither of his parents carried the Q294X; his father and paternal grandmother carried the R1101H mutation. Analysis of polymorphic genetic markers excluded non-paternity. In conclusion, the proband has a "de novo" mutation of apo B gene resulting in a short truncated apo B form (apo B-6.46). Sporadic cases of FHBL with an apparently recessive transmission may be caused by "de novo" mutations of apo B gene.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abetalipoproteinemia / diagnosis
  • Abetalipoproteinemia / genetics
  • Apolipoproteins B / blood
  • Apolipoproteins B / chemistry
  • Apolipoproteins B / genetics*
  • Base Sequence
  • Carrier Proteins / chemistry
  • Carrier Proteins / genetics
  • Centrifugation, Density Gradient
  • Child
  • Diagnosis, Differential
  • Electrophoresis, Polyacrylamide Gel
  • Exons
  • Genetic Complementation Test
  • Genetic Variation
  • Humans
  • Hypolipoproteinemias / diagnosis
  • Hypolipoproteinemias / genetics*
  • Hypolipoproteinemias / metabolism
  • Molecular Sequence Data
  • Mutation*
  • Pedigree
  • Phenotype

Substances

  • Apolipoproteins B
  • Carrier Proteins
  • microsomal triglyceride transfer protein

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