NT-3 Levels and Function in Individuals With CMT

Inclusion Criteria: * Males or females from 7 years of age or older * Diagnosis of acquired peripheral neuropathy (PN) such as due to diabetes, chemo-induced, autoimmune chronic inflammatory demyelinating polyneuropathy (CIDP) established by a report of electrical studies or with a known genetic CMT diagnosis. Definitive diagnosis of PN is established with a report of electrical studies, EMG/nerve conduction studies.2 * Perform assessments to the best of their ability with reliable results as deemed by the evaluator. * Ability to attend scheduled appointments * Ability to provide informed consent (or assent for ages 9-18) Exclusion Criteria: * Current pregnancy per medical history * Has a medical condition or extenuating circumstances that, in the opinion of the investigator, might compromise the subject's wellbeing, safety, or clinical interpretability