Studying Nerve Function and Structure in Charcot-Marie-Tooth Disease, Anti-MAG Neuropathy and CIDP

Inclusion Criteria: 1. The subject is ≥ 18 years old. AND: 2. A genetically confirmed diagnosis of one of the several CMT subtypes (i.e., CMT1A, CMT1B, CMTX1, CMT2I/J, CMT4B, CMT4D and CMT4J) OR 3. A clinical diagnosis of either Chronic Inflammatory Demyelinating Polyneuropathy or anti-MAG polyneuropathy Exclusion Criteria: 1. Known neuropathy from another cause (e.g., diabetes, chronic renal insufficiency, medications, alcohol), including previous carpal tunnel syndrome surgery. 2. History of exposure to chemotherapeutic agents (e.g., bortezomib, vincristine, cisplatin, taxol, vedotin/auromycin-conjugated antibodies), or other medications (e.g., disulfuram, thalidomide, voriconizole, chronic colchicine use) that can cause neuropathy, active alcohol abuse. 3. History of cancer, other than skin cancer, within 5 years prior to enrollment. 4. Pregnancy or nursing. 5. Known systemic disease that predisposes to neuropathy. 6. Other central nervous system diseases.