HSPB1 and myopathy: As previously mentioned, the p.(Pro209Leu) BAG3 variant leads to neuropathy and myopathy, as is also the case for a number of other NMD genes,34 including the bicaudal Drosophila homologue 2 (BICD2),35,36 valosin-containing protein (VCP),37 small heat-shock proteins 1 and 8 (HSPB1 and HSPB8)38-41 and, more recently, the von Willebrand Factor A domain containing 1 (VWA1) gene.42 The BAG3 protein is a co-chaperone implicated in multiple protein–protein interactions, including binding the HSP70 system and small heat-shock proteins (HSPB), and it plays a crucial role in protein quality control.