TGM2 and obesity due to melanocortin 4 receptor deficiency: Increased fat mass in obesity is associated with an increase in adipocyte cell size and/or adipocyte number which are reactions to expand adipose tissue upon need to increase energy storage.3 Defects in this expansion are linked to obesity-linked comorbidities such as development of type 2 diabetes.4, 5 In this work, we have identified a new factor, TG2 that maintains preadipocyte state and thus acts as a negative regulator of adipogenesis.