 The protocol consists of two anonymous surveys. The first large scale survey is designed to identify items that best reflect the issues and symptoms with high impact upon QOL in CMT. A second brief survey focuses on the frequency and impact of muscle cramps on QOL in adult CMT. The surveys will be distributed via an online link to all adult CMT patients self-registered with the RDCRN contact registry. Those who complete the first two surveys will be requested to complete only the second brief survey on muscle cramps again 3 weeks after completing it the first time. Those who complete the brief muscle cramps survey a second time will be requested to complete it again 5 weeks later to assess variability in occurrence of muscle cramps. 