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Charcot-Marie-Tooth disease axonal type 2N(CMT2N)

MedGen UID:
413754
Concept ID:
C2750090
Disease or Syndrome
Synonyms: CHARCOT-MARIE-TOOTH DISEASE, AXONAL, AUTOSOMAL DOMINANT, TYPE 2N; Charcot-Marie-Tooth disease, type 2N; Charcot-Marie-Tooth Neuropathy Type 2N; CHARCOT-MARIE-TOOTH NEUROPATHY, AXONAL, TYPE 2N; CMT2N
SNOMED CT: Autosomal dominant Charcot-Marie-Tooth disease type 2N (719515001)
Modes of inheritance:
Autosomal dominant inheritance
MedGen UID:
141047
Concept ID:
C0443147
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 heterozygotes. In the context of medical genetics, an autosomal dominant disorder is caused when a single copy of the mutant allele is present. Males and females are affected equally, and can both transmit the disorder with a risk of 50% for each child of inheriting the mutant allele.
 
Gene (location): AARS1 (16q22.1)
 
Monarch Initiative: MONDO:0013212
OMIM®: 613287
Orphanet: ORPHA228174

Definition

A mild form of axonal Charcot-Marie-Tooth disease, a peripheral sensorimotor neuropathy, with characteristics of distal legs sensory loss and weakness that can be asymmetric. Tendon reflexes are reduced in the knees and absent in ankles. Progression is slow. [from SNOMEDCT_US]

Clinical features

From HPO
Absent Achilles reflex
MedGen UID:
108240
Concept ID:
C0558845
Finding
Absence of the Achilles reflex (also known as the ankle jerk reflex), which can normally be elicited by tapping the tendon is tapped while the foot is dorsiflexed.
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).
Hammertoe
MedGen UID:
209712
Concept ID:
C1136179
Anatomical Abnormality
Hyperextension of the metatarsal-phalangeal joint with hyperflexion of the proximal interphalangeal (PIP) joint.
Lower limb muscle weakness
MedGen UID:
324478
Concept ID:
C1836296
Finding
Weakness of the muscles of the legs.
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.
Sensorineural hearing loss disorder
MedGen UID:
9164
Concept ID:
C0018784
Disease or Syndrome
A type of hearing impairment in one or both ears related to an abnormal functionality of the cochlear nerve.
Areflexia
MedGen UID:
115943
Concept ID:
C0234146
Finding
Absence of neurologic reflexes such as the knee-jerk reaction.
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.
Distal sensory impairment
MedGen UID:
335722
Concept ID:
C1847584
Finding
An abnormal reduction in sensation in the distal portions of the extremities.
Decreased motor nerve conduction velocity
MedGen UID:
388130
Concept ID:
C1858729
Finding
A type of decreased nerve conduction velocity that affects the motor neuron.
Distal muscle weakness
MedGen UID:
140883
Concept ID:
C0427065
Finding
Reduced strength of the musculature of the distal extremities.
Muscular atrophy
MedGen UID:
892680
Concept ID:
C0541794
Pathologic Function
The presence of skeletal muscular atrophy (which is also known as amyotrophy).
Distal lower limb amyotrophy
MedGen UID:
324515
Concept ID:
C1836451
Disease or Syndrome
Muscular atrophy of distal leg muscles.

Term Hierarchy

CClinical test,  RResearch test,  OOMIM,  GGeneReviews,  VClinVar  
Follow this link to review classifications for Charcot-Marie-Tooth disease axonal type 2N in Orphanet.

Recent clinical studies

Prognosis

Jennings MJ, Kagiava A, Vendredy L, Spaulding EL, Stavrou M, Hathazi D, Grüneboom A, De Winter V, Gess B, Schara U, Pogoryelova O, Lochmüller H, Borchers CH, Roos A, Burgess RW, Timmerman V, Kleopa KA, Horvath R
Brain 2022 Nov 21;145(11):3999-4015. doi: 10.1093/brain/awac055. PMID: 35148379Free PMC Article

Clinical prediction guides

Jennings MJ, Kagiava A, Vendredy L, Spaulding EL, Stavrou M, Hathazi D, Grüneboom A, De Winter V, Gess B, Schara U, Pogoryelova O, Lochmüller H, Borchers CH, Roos A, Burgess RW, Timmerman V, Kleopa KA, Horvath R
Brain 2022 Nov 21;145(11):3999-4015. doi: 10.1093/brain/awac055. PMID: 35148379Free PMC Article

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