In the non-NAFLD group, serum RCAN2 was found to be positively associated with TP (r = 0.137), ALB (r = 0.129), TC (r = 0.191), TG (r = 0.182), and LDL-C (r = 0.119), and negatively associated with HC (r = −0.113) (all p < 0.05). The gene discussed is RCAN2; the disease is metabolic dysfunction-associated steatotic liver disease.