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 1A

Información en español


Other Names:
Charcot-Marie-Tooth disease, demyelinating, type 1A; CMT 1A; Hereditary motor and sensory neuropathy 1A; Charcot-Marie-Tooth disease, demyelinating, type 1A; CMT 1A; Hereditary motor and sensory neuropathy 1A; HMSN 1A; Charcot Marie Tooth disease type 1A See More
Categories:
Charcot-Marie-Tooth disease type 1A (CMT1A) is a type of inherited neurological disorder that affects the peripheral nerves. People with this disease experience weakness and wasting (atrophy) of the muscles of the lower legs beginning in adolescence; later they can also have hand weakness and sensory loss.[1] In CMT1A, abnormal nerve conduction studies can be found in babies or toddlers, but the symptoms that are characteristic of the disease may not occur until 20 years of age or later.[2] CMT1A is caused by having an extra copy (a duplication) of the PMP22 gene.[1][2]  It is inherited in an autosomal dominant manner. Treatment for this condition may include physical therapy; occupational therapy; braces and other orthopedic devices; orthopedic surgery; and pain medications.[1] The severity and degree of disability varies very much among the affected people.[2]
Last updated: 4/17/2018
Usually, people with CMT1A are slow runners in childhood, can develop high arches and hammertoes and often require the use of braces for ankle support. They may have hand weakness, that appear about 10 years after foot and leg problems. Problems with balance because of ankle weakness and loss of proprioception (the brain’s ability to know where the limbs are in space) are common. Most patients (95 percent) remain ambulatory throughout their lives and life expectancy is normal.[2][3]

Last updated: 4/17/2018

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.

Showing of 38 |
Medical Terms Other Names
Learn More:
HPO ID
30%-79% of people have these symptoms
Decreased motor nerve conduction velocity 0003431
Decreased sensory nerve conduction velocity 0003448
Distal muscle weakness
Weakness of outermost muscles
0002460
Distal sensory impairment
Decreased sensation in extremities
0002936
Hyporeflexia
Decreased reflex response
Decreased reflexes
[ more ] 		0001265
Pes cavus
High-arched foot
0001761
Sensory ataxia 0010871
Skeletal muscle atrophy
Muscle degeneration
Muscle wasting
[ more ] 		0003202
5%-29% of people have these symptoms
Acute demyelinating polyneuropathy 0007131
Calf muscle hypertrophy
Increased size of calf muscles
0008981
Diaphragmatic weakness
Weak diaphragm
0009113
Gait imbalance
Abnormality of balance
Abnormality of equilibrium
Imbalanced walk
[ more ] 		0002141
Kyphoscoliosis 0002751
Paresthesia
Pins and needles feeling
Tingling
[ more ] 		0003401
Shoulder pain 0030834
Spontaneous pain sensation 0010833
1%-4% of people have these symptoms
Hyperactive deep tendon reflexes 0006801
Percent of people who have these symptoms is not available through HPO
Areflexia
Absent tendon reflexes
0001284
Autosomal dominant inheritance 0000006
Cold-induced muscle cramps 0003449
Decreased number of peripheral myelinated nerve fibers 0003380
Distal amyotrophy
Distal muscle wasting
0003693
Foot dorsiflexor weakness
Foot drop
0009027
Hammertoe
Hammer toe
Hammertoes
[ more ] 		0001765
Hearing impairment
Deafness
Hearing defect
[ more ] 		0000365
Hypertrophic nerve changes 0003382
Insidious onset
Gradual onset
0003587
Juvenile onset
Signs and symptoms begin before 15 years of age
0003621
Limb muscle weakness
Limb weakness
0003690
Myelin outfoldings 0004336
Onion bulb formation 0003383
Peripheral neuropathy 0009830
Segmental peripheral demyelination/remyelination 0003481
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
Ulnar claw 0001178
Variable expressivity 0003828
Showing of 38 |
Last updated: 7/1/2020
CMT1A is inherited in an autosomal dominant manner.[2] This means that having a change (mutation) in only one copy of the responsible gene in each cell is enough to cause features of the condition.

In some cases, an affected person inherits the mutated gene from an affected parent. In other cases, the mutation occurs for the first time in a person with no family history of the condition. This is called a de novo mutation.

When a person with a mutation that causes an autosomal dominant condition has children, each child has a 50% (1 in 2) chance to inherit that mutation.
Last updated: 1/10/2017

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

Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Clinical Research Resources

  • ClinicalTrials.gov lists trials that are related to Charcot-Marie-Tooth disease type 1A. Click on the link to go to ClinicalTrials.gov to read descriptions of these studies.

    Please note: Studies listed on the ClinicalTrials.gov website are listed for informational purposes only; being listed does not reflect an endorsement by GARD or the NIH. We strongly recommend that you talk with a trusted healthcare provider before choosing to participate in any clinical study.
  • The Research Portfolio Online Reporting Tool (RePORT) provides access to reports, data, and analyses of research activities at the National Institutes of Health (NIH), including information on NIH expenditures and the results of NIH-supported research. Although these projects may not conduct studies on humans, you may want to contact the investigators to learn more. To search for studies, enter the disease name in the "Text Search" box. Then click "Submit Query".

Patient Registry

  • The Inherited Neuropathies Consortium is a team of doctors, nurses, research coordinators, and research labs throughout the U.S., working together to improve the lives of people with Charcot Marie Tooth disease through research. The Inherited Neuropathies Consortium has a registry for patients who wish to be contacted about clinical research opportunities.

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

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

  • Genetics Home Reference (GHR) contains information on Charcot-Marie-Tooth disease type 1A. This website is maintained by the National Library of Medicine.
  • The Muscular Dystrophy Association has developed an information page entitled "Surgery Sometimes, Bracing Often, Caution Always: Caring for the CMT-affected Foot." Click on Muscular Dystrophy Association to view this information page.
  • MedlinePlus was designed by the National Library of Medicine to help you research your health questions, and it provides more information about this topic.
  • The National Institute of Neurological Disorders and Stroke (NINDS) collects and disseminates research information related to neurological disorders. Click on the link to view information on this topic.
  • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.

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. 
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Charcot-Marie-Tooth disease type 1A. Click on the link to view a sample search on this topic.

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. Submit a new question

  • My daughter's father was diagnosed with CMT1A in childhood. My daughter is very active and we decided to not have her tested, unless she shows symptoms. I have noticed that her hands sometimes shake. Should this be a concern? Also she walks on her tip toes. She has since she started walking. However I did too as a child and I don't have the disease. Her father has stated that he has never been physically able to walk on his toes even as a child. I read so many things on the internet and it's so confusing. Her feet do not look abnormal. Anyway I was just wondering about the toe walking and the hands shaking sometimes. See answer

  • Do people with CMT type 1A relapse or does the illness just progress to a more advanced stage? I am aware that it is progressive. I have not read or heard of relapses in this disease, but as it is similar to MS, wondered whether this is a possibility or whether the illness itself is progressing and I will therefore have to learn to accept it. I have experienced periods similar to this but never as extreme. See answer


  1. 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.
  2. Bird TD. Charcot-Marie-Tooth Neuropathy Type 1. GeneReviews. March 26, 2015; http://www.ncbi.nlm.nih.gov/books/NBK1205/.
  3. Francisco de Assis Aquino Gondim. Hereditary Neuropathies of the Charcot-Marie-Tooth Disease Type. Medscape Reference. 2014; http://emedicine.medscape.com/article/1173484-overview#a1.