Leptin levels significantly correlating with BMI (r = 0.6159, p = 0.003), % body fat (r = 0.6089, p = 0.002), fasting insulin (r = 0.5968, p = 0.005), IL-6 (r = 0.5938, p = 0.005) and CRP (r = 0.6038, p = 0.001) in OSA and NAFLD group. The gene discussed is IL6; the disease is obstructive sleep apnea syndrome.