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Start free with EleplanCharcot-Marie-Tooth disease type 4D
ORPHA:99950Disease
Also called CMT4D · HMSN, Lom type · HMSN-Lom · Hereditary motor and sensory neuropathy, Lom type
What it is
A form of Charcot-Marie-Tooth disease type 4 characterized by a childhood-onset of severe, progressive, demyelinating sensorimotor neuropathy manifesting with distal muscle weakness and atrophy, sensorineural hearing impairment leading to deafness (usually in third decade), severely reduced nerve conduction velocities, and skeletal, especially foot, deformities. Tongue atrophy has also been reported. It was initially reported in the Lom Roma community due to a common founder variant, and called hereditary motor and sensory neuropathy, Lom type. Other variants were reported since.
Key facts
- Age of onset
- Adolescent, 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%
4Common30–79%
6Sometimes5–29%
12- Distal sensory impairment
- Distal upper limb muscle weakness
- Hammertoe
- Inability to walk
- Kyphoscoliosis
- Pes cavus
- Postural tremor
- Proximal muscle weakness
and 4 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.
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