Clinical, molecular and functional characterization of two novel mutations associated to compound heterozygous FHBL

Introduction. Primary hypobetalipoproteinemia (pHBL) is a monogenic heterogeneous condition characterized by total cholesterol (TC) and/or LDL cholesterol (LDL-C) levels below the 5th percentile of the reference population. Heterozygous APOB gene mutations are responsible for the majority of the dominant pHBL causing the familial hypobetalipoproteinemia (FHBL). The clinical phenotype of heterozygous FHBL is usually mild. The homozygous or compound heterozygous APOB mutations are in some cases responsible for a more severe biochemical and clinical phenotype, similar to the abetalipoproteinemia (ABL) due to homozygous mutations in the MTP gene, characterized by intestinal malabsorption, pigme…