Description:
<jats:p>Point mutations in <jats:styled-content style="fixed-case">FUS</jats:styled-content> cause amyotrophic lateral sclerosis (<jats:styled-content style="fixed-case">ALS</jats:styled-content>), a devastating neurodegenerative disease—but do they do that by a loss of the protein's normal function, or by endowing it with novel toxic functions, or both? In this issue of <jats:italic>The <jats:styled-content style="fixed-case">EMBO</jats:styled-content> Journal</jats:italic>, Scekic‐Zahirovic <jats:italic>et al</jats:italic> (<jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#embj201694397-bib-0009" />) report that mutant <jats:styled-content style="fixed-case">FUS</jats:styled-content>, but not the complete loss of <jats:styled-content style="fixed-case">FUS</jats:styled-content>, triggers motor neuron degeneration in mice, arguing for a toxic gain‐of‐function mechanism.</jats:p>