We first demonstrated that CMT4B1 is caused by loss-of-function mutations in the MTMR2 gene (Myotubularin-related 2), which encodes a ubiquitously expressed phospholipid phosphatase acting on PtdIns3P and PtdIns(3,5)P2 phosphoinositides.7 We previously reported that loss of MTMR2 in Schwann cells is both sufficient and necessary to cause myelin outfoldings and aberrant myelin.8,9 However, due to the early onset of the neuropathy with fast progression, a cell autonomous role of MTMR2 in neurons/axons cannot be excluded. Here, MTMR2 is linked to neuropathy.