A deficiency in the oxidation of phytol, as in mice deficient in phytanoyl-CoA hydroxylase, can lead to a severe phenotype characterized by the accumulation of phytanic acid with or without elevated pristanic acid, resulting in liver failure, hepatic steatosis, infiltration of inflammatory cells, and peripheral neuropathy7,31,38. The gene discussed is PHYH; the disease is Hepatic steatosis.