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Understanding genetics of Charcot-Marie-Tooth disease

Genetics of Charcot Marie Tooth Disease (CMT) - Modifiers of CMT1A, New Causes of CMT

Observational University of Iowa · NCT01193088

This study is trying to find new genes that cause Charcot-Marie-Tooth disease and see how they affect symptoms in people with CMT type 1A.

Quick facts

Study typeObservational
Enrollment1050 (estimated)
SexAll
SponsorUniversity of Iowa Academic / other
Locations22 sites (Los Angeles, California and 21 other locations)
Trial IDNCT01193088 on ClinicalTrials.gov

What this trial studies

This project aims to identify new genes responsible for Charcot-Marie-Tooth disease (CMT) and to explore modifier genes that influence the severity of symptoms in patients with CMT type 1A (CMT1A). Eligible participants will either have a confirmed diagnosis of CMT1A or an unknown form of CMT. Blood samples will be collected and analyzed through exome sequencing at the University of Miami to uncover genetic factors associated with the disease. Participation is voluntary, and subjects will be informed about the optional nature of the genetic testing.

Who should consider this trial

Good fit: Ideal candidates include individuals diagnosed with CMT1A or those with a family history of the disease linked to PMP22 duplication.

Not a fit: Patients without a documented PMP22 duplication or a clear familial connection to CMT1A may not benefit from this study.

Why it matters

Potential benefit: If successful, this research could lead to better understanding and management of Charcot-Marie-Tooth disease, potentially improving patient outcomes.

How similar studies have performed: Other studies focusing on genetic factors in CMT have shown promise, but this specific approach to identifying modifier genes is relatively novel.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

All patients must agree to take part in the study and sign a consent form. A teenager (age 13-17 years) considering enrolling must agree to take part in the study and sign an assent form (depending on local ethics committee requirements).

Additional inclusion criteria are described below.

Inclusion Criteria: CMT1A Gene Modifier Study

Patients must have at least one of the following:

1. Patient has a documented PMP22 duplication. AND/OR
2. Patient has a first or second degree relative (parent, child, sibling, half- sibling, aunt, uncle, grandparent, grandchild, niece, or nephew) with a documented PMP22 duplication AND a clear link between that family member and the affected patient AND a phenotype consistent with CMT1A.

i. A clear link is necessary for a second-degree relative. For example, if a grandparent is affected and has a PMP22 duplication, and the parent does not have any signs, symptoms, or electrophysiology consistent with CMT1A, there is no clear link.

ii. In cases where clear links are not available, genetic testing is required for the patient or the first degree family member who is not clearly affected.

Inclusion Criteria - Patients for CMT Exome Project

a. Patient has demonstrated neuropathy on nerve conduction studies or clinically diagnosed genetic neuropathy, in the opinion of the investigator or genetic counsellor.

Inclusion Criteria - Controls for CMT Exome Project

1. Person is a family member of a CMT patient who is enrolled in the CMT Exome Project.

   AND one of the following:
2. Person does not have a peripheral neuropathy, in the opinion of the investigator or genetic counsellor.

   OR
3. Person is suspected to have a peripheral neuropathy, but has not been examined at an INC site.

Exclusion Criteria

1. Patient does not wish to participate or does not sign a consent form.
2. For CMT Exome Project, patient has a genetically confirmed form of CMT (i.e. mutation in MFN2 causing CMT2A, mutation in GARS causing CMT2D, etc.).
3. Patients with known neuropathy from a non-genetic source, such as chemotherapies (i.e. Vincristine, Taxol, Cisplatin), diabetes, alcoholism will be evaluated independently so that genetic contributions to their effects on CMT1A phenotypes can also be analyzed.

Where this trial is running

Los Angeles, California and 21 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov → Find more trials like this →
Conditions Charcot-Marie-Tooth Disease, Type IaHMSNCMTCMT1A
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.