This revealed significantly greater area density of expression (percentage of section positively labeled for the marker in question) in the spinal cord than in the motor cortex for Iba1 (U = 7, p = 0.006), HLA‐DR (U = 0, p = 0.0001), TYROBP (U = 0, p = 0.002), and TREM2 (U = 0, p = 0.0004) for control white matter, HLA‐DR (U = 0, p = 0.0001), CD163 (U = 4, p = 0.014), and TREM2 (U = 0, p = 0.0004) for control gray matter, and all markers in the spinal cord compared to the precentral gyrus in the ALS/MND cases (all p ≤ 0.012). This evidence concerns the gene AIF1 and amyotrophic lateral sclerosis.