Homozygous hypobetalipoproteinemia (Ho-HBL; OMIM 107730) is another extremely rare inherited disorder characterized by improper packaging and secretion of apoB-containing lipoproteins due to mutations in both alleles of the APOB gene (Schonfeld, 2003; Tarugi and Averna, 2011). Here, APOB is linked to hypobetalipoproteinemia.