KLB and irritable bowel syndrome: The rs17618244 (G > A) polymorphism of the β-klotho gene and rs1966265 (G > A) of the fibroblast growth factor 4 gene are associated with irritable bowel syndrome with accelerated transit, and the rs17618244 (G > A) polymorphism of the β-klotho gene is associated with the hepatocytes ballooning and necrosis reflecting increased lipotoxicity [58,59].