Farber disease (OMIM 22800) is an ultra rare (about 80 individuals affected by this condition have been reported worldwide) progressive multisystemic neurodevelopmental storage disorder caused by a deficiency of the lysosomal enzyme acid ceramidase (N-acylsphingosine deacylase, EC 3.5.1.23; AC) due to mutations in the acid ceramidase gene (ASAH1) [65]. Here, ASAH1 is linked to Farber lipogranulomatosis.