The extent to which these responses are activated in CMT1A is unclear, though there have been studies suggesting UPR activation in a CMT1A mouse model carrying seven copies of the human PMP22 gene, the C22 mouse, which shows a severe dysmyelinating neuropathy [15], and in Trembler J (TrJ) mice [16], which are caused by a missense mutation in Pmp22 [17]. This evidence concerns the gene PMP22 and neuropathy.