National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Charcot-Marie-Tooth disease type 1

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Other Names:
Autosomal dominant demyelinating Charcot-Marie-Tooth disease; CMT1; Hereditary motor and sensory neuropathy type 1; Autosomal dominant demyelinating Charcot-Marie-Tooth disease; CMT1; Hereditary motor and sensory neuropathy type 1; Charcot-Marie-Tooth type 1; Charcot-Marie-Tooth neuropathy type 1; HMSN1; Hereditary motor and sensory neuropathy 1 See More
Subtypes:
Charcot-Marie-Tooth disease type 1A; Charcot-Marie-Tooth disease type 1B; Charcot-Marie-Tooth disease type 1C; Charcot-Marie-Tooth disease type 1A; Charcot-Marie-Tooth disease type 1B; Charcot-Marie-Tooth disease type 1C; Charcot-Marie-Tooth disease type 1D; Charcot-Marie-Tooth disease type 1E; Charcot-Marie-Tooth disease type 1F See More
This disease is grouped under:
Charcot-Marie-Tooth disease type 1 (CMT1) is a type of peripheral neuropathy, a condition affecting the transmission of information between the central nervous system (brain and spinal cord) and the rest of the body. Symptoms often begin between age 5 and 25, and the condition is usually slowly progressive. Signs and symptoms include distal muscle weakness and wasting (atrophy); sensory loss; and slow nerve conduction velocity. It is often associated with pes cavus foot deformity (high arch) and bilateral foot drop. Fewer than 5% of people with CMT1 become wheelchair dependent.[1]

CMT1 is inherited in an autosomal dominant manner. There are 6 different subtypes CMT1A CMT1B, CMT1C, CMT1D and CMT1F/ CMT2E, caused by different pathogenic variants (mutations)involving the PMP22 gene (designated CMT1A), or the MPZ, LITAF, EGR2, PMP22 or NEFL genes.[1]

Treatment may involve physical or occupational therapy; the use of special shoes, braces or other orthopedic devices; surgery for severe pes cavus; canes or wheelchairs for mobility; and pain medication as needed.[1][2]
Last updated: 4/19/2018

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

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Medical Terms Other Names
Learn More:
HPO ID
30%-79% of people have these symptoms
Kyphoscoliosis 0002751
Peripheral demyelination 0011096
Percent of people who have these symptoms is not available through HPO
Areflexia
Absent tendon reflexes
0001284
Autosomal dominant inheritance 0000006
Autosomal recessive inheritance 0000007
Childhood onset
Symptoms begin in childhood
0011463
Clusters of axonal regeneration 0007233
Cold-induced muscle cramps 0003449
Decreased motor nerve conduction velocity 0003431
Decreased number of peripheral myelinated nerve fibers 0003380
Distal amyotrophy
Distal muscle wasting
0003693
Distal muscle weakness
Weakness of outermost muscles
0002460
Distal sensory impairment
Decreased sensation in extremities
0002936
Foot dorsiflexor weakness
Foot drop
0009027
Hammertoe
Hammer toe
Hammertoes
[ more ] 		0001765
Hearing impairment
Deafness
Hearing defect
[ more ] 		0000365
Hypertrophic nerve changes 0003382
Hyporeflexia
Decreased reflex response
Decreased reflexes
[ more ] 		0001265
Insidious onset
Gradual onset
0003587
Juvenile onset
Signs and symptoms begin before 15 years of age
0003621
Limb muscle weakness
Limb weakness
0003690
Motor delay 0001270
Myelin outfoldings 0004336
Onion bulb formation 0003383
Peripheral neuropathy 0009830
Pes cavus
High-arched foot
0001761
Segmental peripheral demyelination/remyelination 0003481
Sensorineural hearing impairment 0000407
Slow progression
Signs and symptoms worsen slowly with time
0003677
Split hand
Claw hand
Claw hand deformities
Claw hands
Claw-hand deformities
Split-hand
[ more ] 		0001171
Steppage gait
High stepping
0003376
Talipes calcaneovalgus 0001884
Tonic pupil 0012074
Ulnar claw 0001178
Upper limb muscle weakness
Decreased arm strength
Weak arm
[ more ] 		0003484
Variable expressivity 0003828
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Last updated: 7/1/2020
A diagnosis of Charcot-Marie-Tooth disease type 1 (CMT1) can be made based on signs and symptoms and molecular genetic testing.[1] People with symptoms of CMT1 should be evaluated by a neurologist. Evaluation may include a thorough neurological exam, special nerve studies, and consideration of medical and family histories.[1][3] If CMT is suspected, tests that may be ordered include:
  • nerve conduction studies - electrodes are placed on the skin over nerves and produce small electric shocks. This stimulates the nerves and provides quantifiable information for the doctor.
  • electromyography (EMG) - involves inserting a needle electrode through the skin to measure the bioelectrical activity of muscles. Specific abnormalities in the readings can be useful in characterizing the distribution and severity of peripheral nerve involvement.[3]
A clinical diagnosis may be considered in individuals with:
  • progressive peripheral motor and sensory neuropathy
  • slow nerve conduction velocity (NCV)
  • palpably enlarged nerves, especially the ulnar nerve at the elbow and the greater auricular nerve running along the side of the neck
  • a family history consistent with autosomal dominant inheritance[1]
Genetic testing results can usually confirm a diagnosis.[3] Different genetic testing strategies have been proposed in people with symptoms of CMT1, as several genes are associated with the condition. One testing strategy involves testing a single gene at a time, starting with the gene most commonly responsible, and ending with gene least commonly responsible. An alternative genetic testing strategy is using a multi-gene panel that includes all genes of interest.[1] Molecular genetic testing is needed to distinguish the subtype of CMT1 (type A through F), which is based on the responsible gene and mutation.

The Genetic Testing Registry (GTR) provides information about the genetic tests for CMT1. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.
Last updated: 4/19/2018
The long-term outlook (prognosis) for people with Charcot-Marie-Tooth disease type 1 (CMT1) varies because the severity of the condition varies. Some people with CMT1 have extremely mild disease that goes unrecognized, while others have considerable weakness and disability.[4]

In general, the condition is slowly progressive (gradual).[3][5] Affected individuals often experience long periods without obvious deterioration. Most people with CMT1 remain ambulatory throughout life with fewer than 5% becoming wheelchair dependent.[4][1] Life expectancy for affected individuals is normal.[4][3][1]
Last updated: 4/19/2018

If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

Healthcare Resources

Related diseases are conditions that have similar signs and symptoms. A health care provider may consider these conditions in the table below when making a diagnosis. Please note that the table may not include all the possible conditions related to this disease.

Conditions with similar signs and symptoms from Orphanet
Differential diagnosis includes other genetic neuropathies, especially X-linked CMT, autosomal dominant CMT2, CMT4, and hereditary neuropathy with liability to pressure palsies (see these terms). CMT1 identification may be challenging when there is no family history and acquired demyelinating neuropathies must also be taken into account.
Visit the Orphanet disease page for more information.

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

Living with a genetic or rare disease can impact the daily lives of patients and families. These resources can help families navigate various aspects of living with a rare disease.

Community Resources

  • The Job Accommodation Network (JAN) has information on workplace accommodations and disability employment issues related to this condition. JAN is a service of the Office of Disability Employment Policy in the U.S. Department of Labor.

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

In-Depth Information

  • GeneReviews provides current, expert-authored, peer-reviewed, full-text articles describing the application of genetic testing to the diagnosis, management, and genetic counseling of patients with specific inherited conditions.
  • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
    Charcot-Marie-Tooth disease type 1A
    Charcot-Marie-Tooth disease type 1B
    Charcot-Marie-Tooth disease type 1C
    Charcot-Marie-Tooth disease type 1D
    Charcot-Marie-Tooth disease type 1E
    Charcot-Marie-Tooth disease type 1F / 2E
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know.

  1. Bird TD. Charcot-Marie-Tooth Neuropathy Type 1. GeneReviews. March 26, 2015; http://www.ncbi.nlm.nih.gov/books/NBK1205/.
  2. Charcot-Marie-Tooth Disease Fact Sheet. National Institute of Neurological Disorders and Stroke Website. May, 2017; http://www.ninds.nih.gov/disorders/charcot_marie_tooth/detail_charcot_marie_tooth.htm.
  3. Charcot-Marie-Tooth Disease Fact Sheet. NINDS. January 14, 2016; http://www.ninds.nih.gov/disorders/charcot_marie_tooth/detail_charcot_marie_tooth.htm.
  4. Davide Pareyson, Chiara Pisciotta. Charcot-Marie-Tooth disease type 1. Orphanet. March, 2016; http://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=en&Expert=65753.
  5. Divakara Kedlaya. Charcot-Marie-Tooth Disease. Medscape Reference. March 14, 2016; http://emedicine.medscape.com/article/1232386-overview.