CDKN1A and obesity due to melanocortin 4 receptor deficiency: Absolute quantification of mRNA levels from lean individuals and individuals with obesity revealed that the expression of senescence-associated beta galactosidase (GLB1), cyclin-dependent kinase inhibitor 1A (CDKN1A), zinc finger matrin-type 3 (ZMAT3) and cyclin-dependent kinase inhibitor 2A (CDKN2A) genes was significantly increased in SkM from middle-aged individuals with obesity compared to lean and young controls (Figure 1A–D).