PTPRN and amyotrophic lateral sclerosis: These included axonal guidance and neurodevelopment (Neurofascin, Semaphorin-7A, Ciliary neurotrophic factor receptor subunit alpha, Peptidyl-glycine alpha-amidating monooxygenase, Neuritin, Disintegrin and metalloproteinase domain-containing protein 22), synapse assembly and function (Calsyntenin-3, Receptor-type tyrosine-protein phosphatase-like N, Neurofascin), neuropeptide signaling [Neuroendocrine protein 7B2, identified as a candidate ALS biomarker in a previous CSF proteomic study (Ranganathan et al., 2005)] and RNA processing (ATP-dependent RNA helicase DHX8).