Recent studies reporting elevated levels of CSF total Tau (t‐tau) in ALS patients compared with controls have generated novel interest in the diagnostic potential of t‐tau for ALS.5, 6 However, there are conflicting results, which ranged between normal5, 6 and increased levels,7, 8 and the prognostic significance of plasma t‐tau in ALS has so far received little attention. The gene discussed is MAPT; the disease is amyotrophic lateral sclerosis.