Previous work has shown that neurons derived from C9orf72 NRE patient iPS cells show increased glutamate receptors (Shi et al, 2018), age‐dependent glutamate sensitivity, and hyperactivity/hypoactivity (Donnelly et al, 2013; Sareen et al, 2013; Wainger et al, 2014; Devlin et al, 2015), and motor neuron excitotoxicity may be a primary mechanism that contributes to ALS disease pathogenesis (Starr & Sattler, 2018). The gene discussed is C9orf72; the disease is amyotrophic lateral sclerosis.