title: Asymptomatic homozygous hypobetalipoproteinemia associated with apolipoprotein B45.2.
abstract: Familial hypobetalipoproteinemia is caused by apolipoprotein (apo) B gene mutations and is frequently associated with a truncated apo-B protein in the plasma. Homozygosity for mutations yielding a truncated apo-B is extremely rare; fewer than five true homozygotes have been described in the world's literature. These patients typically have normal levels of triglycerides and virtually absent low density lipoprotein (LDL) cholesterol. The clinical status of these patients is variable, ranging from asymptomatic in two homozygotes who synthesized a truncated apo-B (apo-B87) to severe neurological disease resulting from vitamin E deficiency in a homozygote who synthesized a shorter apo-B (apo-B50). In this report, we describe a 48-year-old female homozygous for a nonsense mutation resulting in an even shorter apo-B, apo-B45.2. Although this individual had virtually no LDL cholesterol, she was asymptomatic and had normal plasma levels of vitamin E. This case demonstrates that homozygosity for an apo-B mutation associated with a relatively short apo-B truncation can be completely asymptomatic.
authors.affiliation: Gladstone Institute of Cardiovascular Disease, San Francisco, CA 94141-9100.
authors.forename: S G
authors.initials: SG
authors.lastname: Young
authors.forename: B
authors.initials: B
authors.lastname: Bihain
authors.forename: L M
authors.initials: LM
authors.lastname: Flynn
authors.forename: D A
authors.initials: DA
authors.lastname: Sanan
authors.forename: M
authors.initials: M
authors.lastname: Ayrault-Jarrier
authors.forename: B
authors.initials: B
authors.lastname: Jacotot
mesh_terms: D000483:Alleles; D001055:Apolipoproteins B / Q000235:genetics*; D008078:Cholesterol, LDL / Q000097:blood; D005260:Female; D006720:Homozygote; D006801:Humans; D006995:Hypobetalipoproteinemias / Q000235:genetics*; D008875:Middle Aged; D009154:Mutation; D017384:Sequence Deletion; D014810:Vitamin E / Q000097:blood
chemical_list: D001055:Apolipoproteins B; D008078:Cholesterol, LDL; D014810:Vitamin E