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Charcot-Marie-Tooth disease, axonal, autosomal recessive, type 2a2b;(CMT2A2B)

MedGen UID:
934692
Concept ID:
C4310725
Disease or Syndrome
Synonyms: Charcot-Marie-Tooth disease, axonal, autosomal recessive, type 2A2B; Charcot-Marie-Tooth disease, axonal, type 2A2B
 
Gene (location): MFN2 (1p36.22)
 
Monarch Initiative: MONDO:0014906
OMIM®: 617087

Disease characteristics

Excerpted from the GeneReview: MFN2 Hereditary Motor and Sensory Neuropathy
MFN2 hereditary motor and sensory neuropathy (MFN2-HMSN) is a classic axonal peripheral sensorimotor neuropathy, inherited in either an autosomal dominant (AD) manner (~90%) or an autosomal recessive (AR) manner (~10%). MFN2-HMSN is characterized by more severe involvement of the lower extremities than the upper extremities, distal upper-extremity involvement as the neuropathy progresses, more prominent motor deficits than sensory deficits, and normal (>42 m/s) or only slightly decreased nerve conduction velocities (NCVs). Postural tremor is common. Median onset is age 12 years in the AD form and age eight years in the AR form. The prevalence of optic atrophy is approximately 7% in the AD form and approximately 20% in the AR form. [from GeneReviews]
Authors:
Stephan Züchner   view full author information

Additional description

From OMIM
Autosomal recessive axonal CMT2A2B is a neurologic disorder characterized by onset of peripheral neuropathy in the first years of life. Patients have difficulty walking due to distal muscle weakness; upper limbs may also be affected. Sensory impairment is more variable. Patients often have optic atrophy (summary by Polke et al., 2011).  http://www.omim.org/entry/617087

Clinical features

From HPO
Clubfoot
MedGen UID:
3130
Concept ID:
C0009081
Congenital Abnormality
Clubfoot is a congenital limb deformity defined as fixation of the foot in cavus, adductus, varus, and equinus (i.e., inclined inwards, axially rotated outwards, and pointing downwards) with concomitant soft tissue abnormalities (Cardy et al., 2007). Clubfoot may occur in isolation or as part of a syndrome (e.g., diastrophic dysplasia, 222600). Clubfoot has been reported with deficiency of long bones and mirror-image polydactyly (Gurnett et al., 2008; Klopocki et al., 2012).
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).
Foot dorsiflexor weakness
MedGen UID:
356163
Concept ID:
C1866141
Finding
Weakness of the muscles responsible for dorsiflexion of the foot, that is, of the movement of the toes towards the shin. The foot dorsiflexors include the tibialis anterior, the extensor hallucis longus, the extensor digitorum longus, and the peroneus tertius muscles.
Hearing impairment
MedGen UID:
235586
Concept ID:
C1384666
Disease or Syndrome
A decreased magnitude of the sensory perception of sound.
Abnormally high-pitched voice
MedGen UID:
66836
Concept ID:
C0241703
Finding
A persistent (minutes to hours) abnormal increase in the pitch (frequency) of the voice for the context or social situation or significantly different from baseline of the individual.
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.
Peripheral axonal neuropathy
MedGen UID:
266071
Concept ID:
C1263857
Disease or Syndrome
An abnormality characterized by disruption of the normal functioning of peripheral axons.
Delayed gross motor development
MedGen UID:
332508
Concept ID:
C1837658
Finding
A type of motor delay characterized by a delay in acquiring the ability to control the large muscles of the body for walking, running, sitting, and crawling.
Distal sensory impairment
MedGen UID:
335722
Concept ID:
C1847584
Finding
An abnormal reduction in sensation in the distal portions of the extremities.
Decreased number of large peripheral myelinated nerve fibers
MedGen UID:
395303
Concept ID:
C1859606
Finding
A reduced number of large myelinated nerve fibers.
Kyphosis
MedGen UID:
44042
Concept ID:
C0022821
Anatomical Abnormality
Exaggerated anterior convexity of the thoracic vertebral column.
Scoliosis
MedGen UID:
11348
Concept ID:
C0036439
Disease or Syndrome
The presence of an abnormal lateral curvature of the spine.
Proximal muscle weakness
MedGen UID:
113169
Concept ID:
C0221629
Finding
A lack of strength of the proximal muscles.
Upper limb amyotrophy
MedGen UID:
867165
Concept ID:
C4021523
Disease or Syndrome
Muscular atrophy involving the muscles of the upper limbs.
Lower limb amyotrophy
MedGen UID:
870475
Concept ID:
C4024921
Finding
Muscular atrophy affecting the lower limb.
Respiratory insufficiency due to muscle weakness
MedGen UID:
812797
Concept ID:
C3806467
Finding
Optic atrophy
MedGen UID:
18180
Concept ID:
C0029124
Disease or Syndrome
Atrophy of the optic nerve. Optic atrophy results from the death of the retinal ganglion cell axons that comprise the optic nerve and manifesting as a pale optic nerve on fundoscopy.
Optic disc pallor
MedGen UID:
108218
Concept ID:
C0554970
Finding
A pale yellow discoloration of the optic disc (the area of the optic nerve head in the retina). The optic disc normally has a pinkish hue with a central yellowish depression.

Term Hierarchy

CClinical test,  RResearch test,  OOMIM,  GGeneReviews,  VClinVar  
  • CROGVCharcot-Marie-Tooth disease, axonal, autosomal recessive, type 2a2b;

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