APOB and abetalipoproteinemia: Other mutations of the APOB gene cause hypobetalipoproteinemia (FHBL) (OMIM, 615,558) and abetalipoproteinemia (ABL) (OMIM, 200,100), two rare, autosomal recessive conditions characterized by hypocholesterolemia and malabsorption of lipid-soluble vitamins, which causes retinal degeneration, neuropathy and coagulopathy [16].