ASAH1 and Arthritis: Farber disease (FD) (Online Mendelian Inheritance in Man #228000) is a rare but devastating lysosomal storage disorder (LSD) characterized by deficient acid ceramidase (ACDase) activity.1 Patients carrying two mutant alleles classically present with a triad of symptoms shortly after birth: deforming arthritis, subcutaneous nodules over the joints and pressure areas, and hoarseness of the voice.