APOE and obesity disorder: Genetic testing identified mutations in several genes, including Apolipoprotein E (APOe) E2, APOe E4, Cholesteryl ester transfer protein, Ghrelin, SH2B adaptor protein 1, Solute carrier organic anion transporter family member 1B1, Fat mass and obesity-associated protein, and HNF4a, the latter being diagnostic for MODY type 1.