ASAH1 and Farber lipogranulomatosis: For example, in mice heterozygous for an Asah1 mutation, ceramide accumulates in the liver.43 In humans, patients with Farber disease show reduced activity of ASAH1 due to their genetic defects and exhibit ceramide accumulation in the kidney.44 Taken together, these results strongly indicate that UGCG and ASAH1 are important for regulating ceramide levels.