Of interest, several genes involved in lipid metabolism were up-regulated including Hmgcs2, Bdh2, Acot1, and Acot2. Hmgcr was found to be down-regulated in the liver of SERT−/− mice, as expected due to the hepatic steatosis that develops in SERT−/− mice22. The gene discussed is SLC6A4; the disease is steatosis.