PRKN and obesity due to melanocortin 4 receptor deficiency: One of the more striking phenotypes described in the Park2 KO mouse model was their protection from diet‐induced obesity and hepatosteatosis; after six and a half weeks of high‐fat diet (HFD) feeding, Park2 KO mice weighed 30% less than controls, which was largely attributed to differences in fat mass, and liver fat was also 50% less (Kim et al., 2011).