PNLA also regulated the expression of metabolic genes, including pyruvate dehydrogenase kinase-4 (PDK4) and serpin family E member 1 (SERPINE1) that codes for plasminogen activator inhibitor-1 (PAI-1) from HCs, and fructose-bisphosphatase 1(FBP1), PDK4 and N-Myc downstream regulator 2 (NDRG2) from RA patients [5] as shown in Table 2 and Table 3, respectively. The gene discussed is PDK4; the disease is rheumatoid arthritis.