LEP and obesity due to melanocortin 4 receptor deficiency: Moreover, they noted that after 24 weeks of nourishing a high-fat/high-sucrose diet for wild-type mice, leptin deficiency mice (ob/ob) and Zucker diabetic fatty mice (fa/fa) resulted in obesity phenotype, down-regulation of SFRP5 expression, and overexpression of WNT5A [56].