AGXT and amyotrophic lateral sclerosis: These findings are supported by a recent publication reporting that a monogenic form of ALS is caused by SPTLC1 variants that disrupt the normal homeostatic regulation of serine palmitoyltransferase (SPT) by ORMDL sphingolipid biosynthesis regulator proteins, with the consequent upregulation of SPT activity and increased levels of glycolipids [66].