Charcot Marie Tooth Disease (CMT)

Outline

Background

• Charcot Marie Tooth is the commonest inherited neurological disorder and a frequent PACES station, also known as hereditary motor- sensory neuropathies (HMSN)

• Inheritance is usually autosomal dominant but all inheritance patterns are possible given type

• Most common CMT subtype is HMSN 1, caused by a mutation for the peripheral myelin protein-22 (PMP22) on chromosone 17, this is autosomal dominant

Assessment

Presentation

• Childhood peripheral weakness and numbness

• Family history of peripheral neuropathy

Examination

• Sensory predominant peripheral neuropathy in lower limbs

  • Sensory loss: distal to proximal, variable modalities-

    • Rhomberg's positive: sensory ataxia/ reduced proprioception

  • Motor loss: LMN distal weakness- reduced power and reflexes

• Bilateral pes cavus and foot orthoses- suggests hereditary cause, sign of long standing muscle imbalances

• Inverted champagne bottle legs- distal muscle wasting

• High stepping gait and foot drop

• Palpable nerves (also seen in Leprosy)

Investigations

• Genetic testing

• Nerve conduction studies- to assess if they are demyelinating or axonal neuropathy to aid for genetic testing

• Peripheral neuropathy bloods: Hb, urea, crp; b12, folate, blood sugar/ HbA1c, immunoglobulins, ANA, protein electrophoresis

Diagnosis

Diagnostic criteria: 

Differentials: other peripheral neuropathies- alcohol, diabetes, nutrition, immune but these take time to be acquired

Classification: based off genetic testing of subtype

severity, aetiology

Management

Chronic:

• MDT

  • Neurology consultant, specialist interest in CMT

  • Genetic Counsellor

  • Orthotics- foot drop, reduce pain

  • Orthopedics

    • PT & dieticians- rehab & nutrition to maintain muscle bulk, walking aids

    • OT- home environment changes; SW- carers to allow to function at home, psychologists

• Lifestyle: exercise, nutrition, wellbeing

• Medical

  • No disease modifying medications

  • Neuropathic pain can be managed with 1) amitriptyline, 2) gabapentinoids, 3) SNRI- duloxetine

• Surgical

  • Orthopaedics- surgical interventions for symptom relief

Resources and References

1. https://www.nhs.uk/conditions/charcot-marie-tooth-disease/

2. https://www.ninds.nih.gov/health-information/disorders/charcot-marie-tooth-disease

Written in 2025