Transcripts altered in the C9ORF72-ALS Drosophila heads include biological processes previously identified in patient-derived neurons (such as cell signalling, stress responses, and ion transport) but also changes in defence/ immune response, lipid/ carbohydrate metabolisms, neurological process and learning/ memory (Fig. 4b, C9-disease). Here, C9 is linked to amyotrophic lateral sclerosis.