As the first-time-in-humans controlled study related to investigation of TLR4 gene polymorphism in NAFLD, our findings contribute to the available data that TLR-4 signaling is pivotal for the pathogenesis of NASH and indicate that the TLR4 codon 299 heterozygous gene mutation (Asp299Gly) in humans may have a preventive role against the genesis of NAFLD.