Inherited disease that affects the peripheral motor and sensory nerves

Aetiology

• AD, AR, X-linked - hundreds of mutations, demyelinating and axonal varieties
• HSMN Ia is the most common type (70%) - autosomal dominant demyelinating neuropathy

Clinical features

Symptoms

• Typical presenting symptom is weakness of the feet and ankle

Signs

• Depressed or absent tendon reflexes with a weakness of foot dorsiflexion at the ankle
• An affected adult typically has a bilateral foot drop, symmetrical atrophy of muscles below the knee (stork leg appearance), pes cavus, atrophy of intrinsic hand muscles, especially the thenar muscles of the thumb, and absent tendon reflexes in both upper and lower extremities

Investigations

• Tests to exclude other causes of neuropathy e.g. bloods, serum and urine protein electrophoresis, muscle biopsy, CSF
• Genetic studies
• Nerve conduction studies

Management

• Currently there are no effective treatments to reverse or slow the underlying disease process
• Management is supportive with input from various members of the MDT