Importantly, a high fat diet led to macrosteatosis without inflammation in the livers of LDL receptor knockout mice whereas the livers of mice double-knockout (LDLR-/- and FXR-/-) mice showed necroinflammation and increased hepatic levels of tumor necrosis factor-α, intercellular adhesion molecule-1, transforming growth factor (TGF)–β, procollagen 1α1, and collagen, suggesting FXR may prevent progression of simple steatosis to NASH. The gene discussed is NR1H4; the disease is steatosis.