VCP and Parkinson disease: Human-induced pluripotent stem cells (iPSCs) are a valuable tool for the study of neurological disorders.17 Patient-derived iPSCs have been used successfully to model a range of neurological conditions, including ALS, Alzheimer’s disease and Parkinson’s disease.18–21 Hall et al.22 modelled p97-related ALS using patient-derived iPSCs and revealed that cytoplasmic TDP-43, ER stress, mitochondrial function and oxidative stress are key differences between healthy control and p97 mutants MNs.