FUNCTIONAL EFFECT OF NOVEL AMINO ACID VARIANTS OF APOLIPOPROTEIN B IN FAMILIAL HYPOBETALIPOPROTEINEMIA

Introduction. Familial Hypobetalipoproteinemia (FHBL) is a codominant disorder characterized by reduced plasma levels of LDL-C and apolipoprotein (apo) B. In 50% of cases FHBL is due to mutations in APOB gene resulting in truncated apoBs of various size. Some mutations in APOB gene resulting in non-conservative amino acid substitutions were reported to cause FHBL. In vitro, these mutations induce the retention of the mutant apoB in the endoplasmic reticulum (ER) and impair the secretion of apoB-containing lipoproteins. In two FHBL subjects we identified two novel amino acid variants (Thr26_27delinsAsn and Tyr102Cys) located in the N-terminal 1000 amino acids of mature apoB. Methods. To inve…