The primary variations in the APOE gene are caused by alleles that translate different protein isoforms that are only differentiated by a single amino acid substitution at positions 112 and 158: The ApoE-ε2 isoform (Cis112Cis158) has been linked to the manifestation of hyperlipoproteinemia type III [14]. The gene discussed is APOE; the disease is hyperlipoproteinemia type 3.