UBQLN2 and amyotrophic lateral sclerosis: Two non-neurological controls (NNC), one fALS case with a Ubiquilin 2 (UBQLN2) mutation, and six sporadic ALS cases were combined with a ‘spike-in’ PEG10 channel containing 5% lysate from cells transfected with HA-PEG10 gag-pol and 95% spinal cord lysate to normalize proteomic background complexity.