Although numerous other mutations of APOB were reported in its entire coding-region, these mutations are known to cause familial hypocholesterolemia (hypobetalipoproteinemia or FHBL) and are mostly nonsense, frameshift, or splicing variants that lead to various C-terminally truncated apoB species20 (Fig. 4). Here, APOB is linked to familial hypobetalipoproteinemia 1.