Nevertheless, robust detection of pTDP‐43 in small volumes of ALS patient plasma remains difficult and is an active area of interest, as it has the potential to provide a plasma‐based measurement for TDP‐43 proteinopathy in ALS patients and to inform when TDP‐43 aggregation starts in pre‐clinical asymptomatic C9 expansion carriers. Here, C9 is linked to amyotrophic lateral sclerosis.