SAA2 and obesity due to melanocortin 4 receptor deficiency: In adipocytes, 367 genes were differentially expressed (FDR < 0.05, |log2FC| > 0.5) between the two groups with an upregulation of Serum Amyloid A1 (SAA1) and SAA2 in the KOA group (Figure 2A,B), both of which are secreted by adipocytes and are linked to obesity, inflammation, and metabolic and cardiovascular disease (Yang et al. 2006).