In contrast to the hyperlipidemia in the HNF4α HET mice, induction of the lipogenic genes Acc and Acly as well as down-regulation of genes important for hepatic catabolism and efflux of lipids appear to be responsible for hepatic lipid accumulation and hypolipidemia in the HFHS-fed HNF4α KO mice. The gene discussed is ACLY; the disease is hyperlipidemia.