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Start free with EleplanCharcot-Marie-Tooth disease type 4A
ORPHA:99948Disease
Also called CMT4A
What it is
A form of Charcot-Marie-Tooth disease type 4 characterized by early-onset (infancy to early childhood) of severe, rapidly progressing axonal, demyelinating, or intermediate sensorimotor neuropathy usually affecting first, and more severely, the distal lower extremities and later the proximal muscles and upper extremities. Nerve conduction velocities range from very slow to normal. Apart from the typical CMT phenotype (distal muscle weakness and atrophy, sensory loss, frequent pes cavus foot deformity), patients commonly present delayed motor development, vocal cord paresis, mild sensory loss, abolished deep tendon reflexes, and skeletal deformities.
Key facts
- Age of onset
- Infancy, Neonatal
- Inheritance
- Autosomal recessive
- Classified as
- Disease
Recorded for the broader condition
- Prevalence
- 1-5 / 10 000 (Europe)Charcot-Marie-Tooth disease type 4
Orphanet records these for the broader condition rather than for this specific form. They are a starting point, not a figure for this subtype — subtypes often differ, and some are defined by being rarer than the condition they sit under.
Signs and symptoms
Very common80–99%
9Common30–79%
20- Areflexia
- Bilateral talipes equinovarus
- Chronic axonal neuropathy
- Decreased Achilles reflex
- Decreased number of large peripheral myelinated nerve fibers
- Hammertoe
- Hand muscle weakness
- Hoarse voice
- Hyporeflexia of upper limbs
- Impaired distal proprioception
- Impaired distal tactile sensation
- Impaired distal vibration sensation
- Impaired pain sensation
- Inability to walk
- Joint contracture of the hand
- Limited interphalangeal movement
- Limited wrist movement
- Motor delay
- Unsteady gait
- Vocal cord paresis
These ranges are how often a sign appears across everyone diagnosed, not a prediction for one person — most people have some of these and not others. Orphanet also records findings that are specifically absent in this disease; those are in the data but not listed here.
Gene
ICD-10 codes
ICD-10 has no distinct code for most rare diseases, so many are filed under the nearest available one. A shared code identifies the group, not this disease — the ORPHAcode above is what identifies it.
Related health topics
Reached through the ICD-10 categories this disease is filed under, so these describe the broader group rather than this disease specifically.
Cross-references
Orphadata Science: Free access data from Orphanet. © INSERM 1999. Data version 2026-06-23. Available under CC BY 4.0. This is a reference, not medical advice.
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