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Charcot-Marie-Tooth disease, type IC(CMT1C)

MedGen UID:
331363
Concept ID:
C1832775
Disease or Syndrome
Synonyms: Charcot-Marie-Tooth disease type 1C; Charcot-Marie-Tooth disease, demyelinating, Type 1C; Charcot-Marie-Tooth Neuropathy Type 1; CHARCOT-MARIE-TOOTH NEUROPATHY, TYPE 1C; CMT 1C; CMT, SLOW NERVE CONDUCTION TYPE C; CMT1C; HMSN IC; NEUROPATHY, HEREDITARY MOTOR AND SENSORY, TYPE IC
Modes of inheritance:
Autosomal dominant inheritance
MedGen UID:
141047
Concept ID:
C0443147
Intellectual Product
Autosomal dominant inheritance refers to genetic conditions that occur when a mutation is present in one copy of a given gene (i.e., the person is heterozygous).
 
Gene: LITAF
Cytogenetic location: 16p13.13
OMIM: 601098

Disease characteristics

Excerpted from the GeneReview: Charcot-Marie-Tooth Neuropathy Type 1
Charcot-Marie-Tooth neuropathy type 1 (CMT1) is a demyelinating peripheral neuropathy characterized by distal muscle weakness and atrophy, sensory loss, and slow nerve conduction velocity. It is usually slowly progressive and often associated with pes cavus foot deformity and bilateral foot drop. Affected individuals usually become symptomatic between age five and 25 years. Fewer than 5% of individuals become wheelchair dependent. Life span is not shortened.  [from GeneReviews]
Full text of GeneReview (by section):
Summary  |  Diagnosis  |  Clinical Description  |  Differential Diagnosis  |  Management  |  Genetic Counseling  |  Resources  |  Molecular Genetics  |  References  |  Chapter Notes
Authors:
Thomas D Bird   view full author information

Additional descriptions

From OMIM
For a phenotypic description and a discussion of genetic heterogeneity of autosomal dominant Charcot-Marie-Tooth disease type 1, see CMT1B (118200).  http://www.omim.org/entry/601098
From GHR
Charcot-Marie-Tooth disease is a group of progressive disorders that affect 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. Charcot-Marie-Tooth disease usually becomes apparent in adolescence or early adulthood, but onset may occur anytime from early childhood through late adulthood. Symptoms of Charcot-Marie-Tooth disease vary in severity, even among members of the same family. Some people never realize they have the disorder, but most have a moderate amount of physical disability. A small percentage of people experience severe weakness or other problems which, in rare cases, can be life-threatening. In most affected individuals, however, Charcot-Marie-Tooth disease does not affect life expectancy. Typically, the earliest symptoms of Charcot-Marie-Tooth disease involve balance difficulties, clumsiness, and muscle weakness in the feet. Affected individuals may have foot abnormalities such as high arches (pes cavus), flat feet (pes planus), or curled toes (hammer toes). They often have difficulty flexing the foot or walking on the heel of the foot. These difficulties may cause a higher than normal step (or gait) and increase the risk of ankle injuries and tripping. As the disease progresses, muscles in the lower legs usually weaken, but leg and foot problems rarely require the use of a wheelchair. Affected individuals may also develop weakness in the hands, causing difficulty with daily activities such as writing, fastening buttons, and turning doorknobs. People with this disorder typically experience a decreased sensitivity to touch, heat, and cold in the feet and lower legs, but occasionally feel aching or burning sensations. In some cases, affected individuals experience gradual hearing loss, deafness, or loss of vision. There are several types of Charcot-Marie-Tooth disease. Type 1 Charcot-Marie-Tooth disease (CMT1) is characterized by abnormalities in myelin, the fatty substance that covers nerve cells, protecting them and helping to conduct nerve impulses. These abnormalities slow the transmission of nerve impulses. Type 2 Charcot-Marie-Tooth disease (CMT2) is characterized by abnormalities in the fiber, or axon, that extends from a nerve cell body and transmits nerve impulses. These abnormalities reduce the strength of the nerve impulse. Type 4 Charcot-Marie-Tooth disease (CMT4) affects either the axon or myelin and is distinguished from the other types by its pattern of inheritance. In intermediate forms of Charcot-Marie-Tooth disease, the nerve impulses are both slowed and reduced in strength, probably due to abnormalities in both axons and myelin. Type X Charcot-Marie-Tooth disease (CMTX) is caused by mutations in a gene on the X chromosome, one of the two sex chromosomes. Within the various types of Charcot-Marie-Tooth disease, subtypes (such as CMT1A, CMT1B, CMT2A, CMT4A, and CMTX1) are distinguished by the specific gene that is altered. Sometimes other, more historical names are used to describe this disorder. For example, Roussy-Levy syndrome is a form of Charcot-Marie-Tooth disease defined by the additional feature of rhythmic shaking (tremors). Dejerine-Sottas syndrome is a term sometimes used to describe a severe, early childhood form of Charcot-Marie-Tooth disease; it is also sometimes called Charcot-Marie-Tooth disease type 3 (CMT3). Depending on the specific gene that is altered, this severe, early onset form of the disorder may also be classified as CMT1 or CMT4. CMTX5 is also known as Rosenberg-Chutorian syndrome. Some researchers believe that this condition is not actually a form of Charcot-Marie-Tooth disease. Instead, they classify it as a separate disorder characterized by peripheral nerve problems, deafness, and vision loss.  http://ghr.nlm.nih.gov/condition/charcot-marie-tooth-disease

Clinical features

Decreased motor nerve conduction velocity
MedGen UID:
500951
Concept ID:
CN003094
Finding
A type of decreased nerve conduction velocity that affects the `motor neuron` (FMA:83617).
Pes cavus
MedGen UID:
425071
Concept ID:
CN001601
Finding
The presence of an unusually high `plantar arch` (FMA:43942). Also called high instep, pes cavus refers to a distinctly hollow form of the sole of the foot when it is bearing weight.
Distal amyotrophy
MedGen UID:
505575
Concept ID:
CN003339
Finding
Muscular atrophy affecting muscles in the distal portions of the extremities.

Term Hierarchy

CClinical test,  RResearch test,  OOMIM,  GGeneReviews

Recent clinical studies

Etiology

Mercuri E, Poulton J, Buck J, Broadbent V, Bamford M, Jungbluth H, Manzur AY, Muntoni F
Arch Dis Child 1999 Nov;81(5):442-3. PMID: 10519723Free PMC Article

Therapy

Mercuri E, Poulton J, Buck J, Broadbent V, Bamford M, Jungbluth H, Manzur AY, Muntoni F
Arch Dis Child 1999 Nov;81(5):442-3. PMID: 10519723Free PMC Article

Prognosis

Mercuri E, Poulton J, Buck J, Broadbent V, Bamford M, Jungbluth H, Manzur AY, Muntoni F
Arch Dis Child 1999 Nov;81(5):442-3. PMID: 10519723Free PMC Article

Clinical prediction guides

Huxley C, Passage E, Robertson AM, Youl B, Huston S, Manson A, Sabéran-Djoniedi D, Figarella-Branger D, Pellissier JF, Thomas PK, Fontés M
Hum Mol Genet 1998 Mar;7(3):449-58. PMID: 9467003

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