Regarding CSF levels of t‐tau in ALS patients, previous studies have yielded similar inconsistent results, which ranged between normal7, 8, 15, 27, 28 and increased levels.5, 6, 29 This inconsistency might be linked to the inherent variability of the disease; for example, variability in release of tau from motor neurons during disease progression. Here, MAPT is linked to amyotrophic lateral sclerosis.