Loss of myelination is exemplified by the changes in G-protein coupled receptors (GPRCs) marking developmental milestones: GPR56, expressed in OPCs41, and GPR37, expressed in myelinating cells42, were lowly expressed in ALS-enriched groups and globally downregulated (Extended Data Fig. 7p). The gene discussed is GPR37; the disease is amyotrophic lateral sclerosis.