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Charcot-Marie-Tooth disease type 4G(CMT4G; HMSNR)

MedGen UID:
343122
Concept ID:
C1854449
Disease or Syndrome
Synonyms: CHARCOT-MARIE-TOOTH DISEASE, DEMYELINATING, TYPE 4G; CHARCOT-MARIE-TOOTH NEUROPATHY, TYPE 4G; Neuropathy, hereditary motor and sensory, Russe type
SNOMED CT: Charcot-Marie-Tooth disease type 4G (715799004); Hereditary motor and sensory neuropathy Russe type (715799004)
Modes of inheritance:
Autosomal recessive inheritance
MedGen UID:
141025
Concept ID:
C0441748
Intellectual Product
Source: Orphanet
A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in individuals with two pathogenic alleles, either homozygotes (two copies of the same mutant allele) or compound heterozygotes (whereby each copy of a gene has a distinct mutant allele).
 
Gene (location): HK1 (10q22.1)
 
Monarch Initiative: MONDO:0011534
OMIM®: 605285
Orphanet: ORPHA99953

Definition

The Russe type of hereditary motor and sensory neuropathy (HMSNR) is an autosomal recessive progressive complex peripheral neuropathy characterized by onset in the first decade of distal lower limb weakness and muscle atrophy resulting in walking difficulties. Distal impairment of the upper limbs usually occurs later, as does proximal lower limb weakness. There is distal sensory impairment, with pes cavus and areflexia. Laboratory studies suggest that it is a myelinopathy resulting in reduced nerve conduction velocities in the demyelinating range as well as a length-dependent axonopathy (summary by Sevilla et al., 2013). For a discussion of genetic heterogeneity of autosomal recessive hereditary motor and sensory neuropathy, also known as Charcot-Marie-Tooth disease, see CMT4A (214400). [from OMIM]

Clinical features

From HPO
Pes cavus
MedGen UID:
675590
Concept ID:
C0728829
Congenital Abnormality
An increase in height of the medial longitudinal arch of the foot that does not flatten on weight bearing (i.e., a distinctly hollow form of the sole of the foot when it is bearing weight).
Distal lower limb muscle weakness
MedGen UID:
324514
Concept ID:
C1836450
Finding
Reduced strength of the distal musculature of the legs.
Distal upper limb muscle weakness
MedGen UID:
461970
Concept ID:
C3150620
Finding
Reduced strength of the distal musculature of the arms.
Peripheral neuropathy
MedGen UID:
18386
Concept ID:
C0031117
Disease or Syndrome
Peripheral neuropathy is a general term for any disorder of the peripheral nervous system. The main clinical features used to classify peripheral neuropathy are distribution, type (mainly demyelinating versus mainly axonal), duration, and course.
Areflexia
MedGen UID:
115943
Concept ID:
C0234146
Finding
Absence of neurologic reflexes such as the knee-jerk reaction.
Paralysis
MedGen UID:
105510
Concept ID:
C0522224
Finding
Paralysis of voluntary muscles means loss of contraction due to interruption of one or more motor pathways from the brain to the muscle fibers. Although the word paralysis is often used interchangeably to mean either complete or partial loss of muscle strength, it is preferable to use paralysis or plegia for complete or severe loss of muscle strength, and paresis for partial or slight loss. Motor paralysis results from deficits of the upper motor neurons (corticospinal, corticobulbar, or subcorticospinal). Motor paralysis is often accompanied by an impairment in the facility of movement.
Gait disturbance
MedGen UID:
107895
Concept ID:
C0575081
Finding
The term gait disturbance can refer to any disruption of the ability to walk.
Hyporeflexia
MedGen UID:
195967
Concept ID:
C0700078
Finding
Reduction of neurologic reflexes such as the knee-jerk reaction.
Distal sensory impairment
MedGen UID:
335722
Concept ID:
C1847584
Finding
An abnormal reduction in sensation in the distal portions of the extremities.
Axonal regeneration
MedGen UID:
340241
Concept ID:
C1854454
Finding
The presence of axonal regeneration following a previous axonal lesion.
Decreased motor nerve conduction velocity
MedGen UID:
388130
Concept ID:
C1858729
Finding
A type of decreased nerve conduction velocity that affects the motor neuron.
Decreased number of large peripheral myelinated nerve fibers
MedGen UID:
395303
Concept ID:
C1859606
Finding
A reduced number of large myelinated nerve fibers.
Peripheral hypomyelination
MedGen UID:
870480
Concept ID:
C4024927
Finding
Reduced amount of myelin in the nervous system resulting from defective myelinogenesis in the peripheral nervous system.
Scoliosis
MedGen UID:
11348
Concept ID:
C0036439
Disease or Syndrome
The presence of an abnormal lateral curvature of the spine.
Distal muscle weakness
MedGen UID:
140883
Concept ID:
C0427065
Finding
Reduced strength of the musculature of the distal extremities.
Distal lower limb amyotrophy
MedGen UID:
324515
Concept ID:
C1836451
Disease or Syndrome
Muscular atrophy of distal leg muscles.
Claw hand deformity
MedGen UID:
1814631
Concept ID:
C5702555
Anatomical Abnormality
An abnormality of the hand characterized by metacarpophalangeal (MCP) hyperextension and proximal interphalangeal (PIP) and distal interphalangeal (DIP) flexion. The position of the affected hand is said to resemble a claw.
Dysphonia
MedGen UID:
282893
Concept ID:
C1527344
Mental or Behavioral Dysfunction
Difficulty in speaking due to a physical disorder of the mouth, tongue, throat, or vocal cords. Associated with a known physical or neurological cause.
Ptosis
MedGen UID:
2287
Concept ID:
C0005745
Disease or Syndrome
The upper eyelid margin is positioned 3 mm or more lower than usual and covers the superior portion of the iris (objective); or, the upper lid margin obscures at least part of the pupil (subjective).

Term Hierarchy

CClinical test,  RResearch test,  OOMIM,  GGeneReviews,  VClinVar  
Follow this link to review classifications for Charcot-Marie-Tooth disease type 4G in Orphanet.

Recent clinical studies

Diagnosis

Goleyjani Moghadam M, Elahi Z, Soveyzi M, Arzhangi S, Nafissi S, Najmabadi H, Kahrizi K, Fattahi Z
Arch Iran Med 2023 May 1;26(5):279-284. doi: 10.34172/aim.2023.43. PMID: 38301092Free PMC Article

Clinical prediction guides

Goleyjani Moghadam M, Elahi Z, Soveyzi M, Arzhangi S, Nafissi S, Najmabadi H, Kahrizi K, Fattahi Z
Arch Iran Med 2023 May 1;26(5):279-284. doi: 10.34172/aim.2023.43. PMID: 38301092Free PMC Article