A recent transcriptome-based study of postmortem frontal cortex tissue from patients with ALS reported a coordinated upregulation of transcripts from a sub-population of microglia (termed disease-associated microglia) and overexpressed neuroinflammatory molecules, such as YKL 40 (also known as CHI3L1) and CHI3L2. Here, CHI3L1 is linked to amyotrophic lateral sclerosis.