Rare Pulmonology News

Disease Profile

Charcot-Marie-Tooth disease type 4B2

Prevalence
Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.

Unknown

Age of onset

Childhood

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ICD-10

G60.0

Inheritance

Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease

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Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype

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X-linked
dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.

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X-linked
recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder

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Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.

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Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.

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Not applicable

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Other names (AKA)

CMT 4B2; Charcot Marie Tooth disease type 4B2; CHARCOT-MARIE-TOOTH DISEASE, WITH FOCALLY FOLDED MYELIN SHEATHS, AUTOSOMAL RECESSIVE, TYPE 4B2;

Categories

Congenital and Genetic Diseases; Nervous System Diseases

Summary

Charcot-Marie-Tooth disease type 4B2 (CMT4B2) is a disorder that affects the peripheral nerves. Peripheral nerves connect the brain and spinal cord to muscles and to sensory cells that detect sensations such as touch, pain, heat, and sound. Damage to the peripheral nerves can result in loss of sensation and wasting (atrophy) of muscles in the feet, legs, and hands.[1] CMT4B2 can also cause glaucoma (damage to the eye’s optic nerve).[2] There is currently no cure for CMT4B2, but physical therapy, occupational therapy, braces and other orthopedic devices, pain medication, and orthopedic surgery can help manage and improve symptoms.[3] CMT4B2 is inherited in an autosomal recessive fashion. It is caused by mutations in the SBF1 gene.[2]

Symptoms

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.

Medical Terms Other Names
Learn More:
HPO ID
Percent of people who have these symptoms is not available through HPO
Areflexia
Absent tendon reflexes
0001284
Autosomal recessive inheritance
0000007
Decreased motor nerve conduction velocity
0003431
Decreased number of peripheral myelinated nerve fibers
0003380
Difficulty walking
Difficulty in walking
0002355
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
Glaucoma
0000501
Hammertoe
Hammer toe
Hammertoes

[ more ]

0001765
Hyporeflexia
Decreased reflex response
Decreased reflexes

[ more ]

0001265
Juvenile onset
Signs and symptoms begin before 15 years of age
0003621
Kyphoscoliosis
0002751
Onion bulb formation
0003383
Pes cavus
High-arched foot
0001761
Segmental peripheral demyelination/remyelination
0003481
Sensorineural hearing impairment
0000407
Split hand
Claw hand
Claw hand deformities
Claw hands
Claw-hand deformities
Split-hand

[ more ]

0001171
Steppage gait
High stepping
0003376
Talipes equinovarus
Club feet
Club foot
Clubfeet
Clubfoot

[ more ]

0001762
Ulnar claw
0001178

Diagnosis

Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

Testing Resources

  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. 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.

    Organizations

    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

      Organizations Providing General Support

        Learn more

        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

        • 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.

          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.
          • 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 4B2. Click on the link to view a sample search on this topic.

            References

            1. Charcot-Marie-Tooth disease. Genetics Home Reference (GHR). December, 2015; https://ghr.nlm.nih.gov/condition/charcot-marie-tooth-disease.
            2. Bird TD. Charcot-Marie-Tooth Neuropathy Type 4. GeneReviews. August 20, 2015; https://www.ncbi.nlm.nih.gov/books/NBK1468/.
            3. Charcot-Marie-Tooth Disease Fact Sheet. NINDS. January 14, 2016; https://www.ninds.nih.gov/disorders/charcot_marie_tooth/detail_charcot_marie_tooth.htm.