Of the six ceramide synthases, ceramide synthase 1 (CERS1) is highly expressed in skeletal muscle (as is CerS5, which has been associated with ALS [49]), with CerS1 being specific for the synthesis of Cer18:1/18:0, the preferred substituents of GM1 [167]. Here, CERS1 is linked to amyotrophic lateral sclerosis.