Charcot-Marie-Tooth (CMT) Disease
What is CMT?
CMT is a common neurological disorder which has a prevalence of 1 in 2,500 people.[1] The disorder was named after three physicians (Jean-Martin Charcot, Pierre Marie and Howard Henry Tooth) who discovered the disease in 1886. The disorder is also known as Hereditary Sensory Motor Neuropathy (HMSN) or peroneal muscular atrophy. CMT affects the peripheral nerves which lie outside the brain and spinal chord. As a result, there is loss of muscle tissue and touch sensation in the limbs. Although CMT is known as a hereditary disorder, about one third of all patients have no family history. [2]
It may be difficult to distinguish CMT from other hereditary and autoimmune neuropathies based on symptoms due to clinical variability and genetic heterogeneity. Even within the same family, disease severity is highly variable. Some individuals may show minimal symptoms and are unaware of being affected, while others may have significant disabilities.
Common Clinical Features [3]:
- Muscles weakness in legs and feet
- Loss of muscle bulk in lower limbs
- Sensory loss in feet
- Foot Drop (inability to lift feet)
- Foot deformities (very high arched feet or flat feet)
- As disease progresses, similar symptoms may be seen in arms and hands
Diagnosing CMT1
Neurologists diagnose CMT by:
- Physical examination
- Medical history
- Electromyography and Nerve Conduction studies
- Genetic testing with a blood test
Treatment
Although there is no cure for CMT, patients can manage their symptoms through[4]:
- Physical therapy and exercise
- Assistive devices (such as foot arthoses)
- Surgery
Proper foot care may help reduce ulcers and painful deformities in the feet.
Benefits of Genetic testing for CMT:
While all tests neurologists perform may suggest CMT, genetic testing pinpoints the cause of CMT with a blood test. Only Athena offers the most comprehensive number of CMT genes in clinically relevant profiles to help diagnose more than 80% of patients with this disorder.
- An accurate diagnosis for CMT allows physicians to:
- Provide prognostic information for the patient
- Determine treatment options
- Avoid certain contra-indicated medications
- Provide inheritance implications
- Help patients join support groups to manage their symptoms such as:
Educational Resources:
Virtual Grand Rounds (VGR) for Healthcare Professionals
Overview of Charcot-Marie-Tooth Disease
by Dr. Michael Shy
Professor of Neurology, Member of Center for Molecular Medicine and Genetics,
Wayne State University School of Medicine
Professor of Neurology, Member of Center for Molecular Medicine and Genetics,
Wayne State University School of Medicine
Patient Education Resource (Download)
Facts about Charcot-Marie-Tooth Disease
CMT brochure (Download)
Provides detailed information on Athena’s CMT genes and clinical profiles
Ordering information (Access Athena Requisition Download)
Reimbursement Resources
Letter of Medical Necessity for CMT
For more information on Athena’s genetic testing services, visit www.athenadiagnostics.com or call 1-800-394-4493.
[1] Szigeti, K. et al. Molecular Diagnostics of Charcot-Marie-Tooth disease and related peripheral neuropathies. 2006. Neuromolecular Medicine. 8:243-253.
[2] Boerkoel, C. et al. Charcot-Marie-Tooth disease and related neuropathies: mutation distribution and genotype-phenotype correlation. Ann Neurol. 2002; (2):190-201.
[3] http://www.ninds.nih.gov/disorders/charcot_marie_tooth, April 22, 2010.
[4] Shy, M. Therapeutic strategies for the inherited neuropathies.2006. NeuroMolecular Medicine. 8:255-278