title: Extreme Contrast of Postprandial Remnant-Like Particles Formed in Abetalipoproteinemia and Homozygous Familial Hypobetalipoproteinemia.
abstract: BACKGROUND
  Familial hypobetalipoproteinemia (FHBL) and abetalipoproteinemia (ABL) are rare inherited forms of hypolipidemia. Their differential diagnosis is important for predicting of the prognosis and selecting appropriate therapy.
  
  
  METHODS
  Genetic analysis was performed in two patients with primary hypocholesterolemia born from consanguineous parents. The oral fat tolerance test (OFTT) was performed in one patient with FHBL (apoB-87.77) and one with ABL as well as in four normal control subjects. After overnight fasting, blood samples were drawn. Serum lipoprotein and remnant-like particle (RLP) fractions were determined by HPLC analysis.
  
  
  RESULTS
  Both patients with homozygous FHBL were asymptomatic probably because of preserved levels of fat-soluble vitamins, especially vitamin E. The patients with FHBL were homozygous because of novel apoB-83.52 and apoB-87.77 mutations, and although one of them (apoB-87.77) had fatty liver disease, microscopic findings suggesting nonalcoholic steatohepatitis were absent. Fasting apoB-48 and RLP-triglyceride levels in the patient with homozygous FHBL, which were similar to those in normal control subjects, increased after OFTT both in normal control subjects and the patient with FHBL but not in the patient with ABL, suggesting that the fat load administered was absorbed only in the patient with FHBL.
  
  
  CONCLUSIONS
  Although lipid levels in the patients with homozygous FHBL and ABL were comparable, fasting, postoral fat loading of apoB-48, as well as RLP-triglyceride levels, may help in the differential diagnosis of FHBL and ABL and provide a prompt diagnosis using genetic analysis in the future.
authors.affiliation: Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medicine, 13-1 Takara-machi, Kanazawa, 920-8641, Japan, mk@med.kanazawa-u.ac.jp.
authors.forename: Masa-Aki
authors.initials: MA
authors.lastname: Kawashiri
authors.forename: Hayato
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authors.lastname: Tada
authors.forename: Marowa
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authors.lastname: Hashimoto
authors.forename: Matsuo
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authors.lastname: Taniyama
authors.forename: Takamitsu
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authors.forename: Chiaki
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authors.lastname: Konno
authors.forename: Kenshi
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authors.lastname: Hayashi
authors.forename: Atsushi
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authors.lastname: Nohara
authors.forename: Akihiro
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authors.lastname: Inazu
authors.forename: Junji
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authors.lastname: Ishihara
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authors.forename: Tsutomu
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authors.lastname: Hirano
authors.forename: Hiroshi
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authors.lastname: Mabuchi
authors.forename: Masakazu
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authors.lastname: Yamagishi