PFN1 and motor neuron disorder: Furthermore, the protein products for several genes that have been causally linked to ALS (Taylor et al, 2016) are found within the M2 module, including HNRNPA1, MATR3, and PFN1 and TDP‐43 itself (Fig 4B), whereas HSPB1 (in M6) has been linked to hereditary motor neuropathy, a form of motor neuron disease (James & Talbot, 2006; Rossor et al, 2011).