Caring for someone with this diagnosis? Eleplan keeps diagnoses, medications, documents and every specialist in one plan.
Start free with EleplanCharcot-Marie-Tooth disease type 4B2
ORPHA:99956Disease
Also called CMT4B2
What it is
A form of Charcot-Marie-Tooth disease type 4 characterized by a severe, early childhood-onset of demyelinating sensorimotor neuropathy, early-onset glaucoma, focally folded myelin sheaths in the peripheral nerves, severely reduced nerve conduction velocities, and the typical CMT phenotype (i.e. distal muscle weakness and atrophy, sensory loss, absence of deep tendon reflexes, and frequent pes cavus). Severe visual impairment leading to visual loss, usually associated with glaucoma, and vocal cord paresis, has also been reported.
Key facts
- Age of onset
- Childhood
- 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%
9Sometimes5–29%
22- Autistic behavior
- Buphthalmos
- Cataract
- Developmental glaucoma
- Hand muscle weakness
- Inability to walk
- Motor delay
- Optic atrophy
and 14 more in this range
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.
Powered by Eleplan
A rare diagnosis is just the start. Eleplan keeps the whole care plan in one place.
Diagnoses, medications, documents, appointments, and the whole care team — organized and always in sync, so you are not retelling the same story to every new specialist. With Ellie, your AI care assistant, on top of it. Free to start.