We have shown previously21,22 that iron accumulation (in the form of ferritin) is associated with TDP-43 burden in symptomatic brain regions in ALS but extending this analysis to additional cases and brain regions and to assess this relationship in ageing and AD is clearly warranted, especially given the association between brain iron accumulation and cognitive dysfunction in ageing cohorts23,24. Here, TARDBP is linked to Alzheimer disease.