SFRP5 and obesity due to melanocortin 4 receptor deficiency: Several studies reported the induction of Sfrp5 gene expression during differentiation of 3T3-L1 adipocytes and in rodent models of genetic and/or diet-induced obesity [7]–[10] and propose a role for Sfrp5 in the adipocyte growth via suppression of the Wnt pathway and inhibition of adipocyte mitochondrial metabolism [9].