Autosomal dominant hereditary demyelinating motor and sensory neuropathy

Autosomal dominant hereditary demyelinating motor and sensory neuropathy, also commonly known as Charcot-Marie-Tooth disease type 1 (CMT1), is a group of inherited peripheral nerve disorders characterized by progressive demyelination of peripheral nerves. Demyelination refers to the loss or damage of the myelin sheath — the protective insulating layer that surrounds nerve fibers — which leads to slowed nerve conduction and progressive nerve dysfunction. The condition primarily affects the peripheral nervous system, impacting both motor nerves (which control muscle movement) and sensory nerves (which transmit sensation). Key clinical features include slowly progressive distal muscle weakness and atrophy, typically beginning in the feet and legs and later affecting the hands and forearms. Patients commonly develop foot deformities such as high arches (pes cavus) and hammer toes, difficulty walking, frequent tripping, and steppage gait. Sensory symptoms include reduced sensation to touch, pain, and temperature in the extremities. Deep tendon reflexes are often diminished or absent. Onset is typically in childhood or adolescence, though the age of onset and severity can vary considerably even within the same family. There is currently no cure for this condition. Treatment is supportive and multidisciplinary, focusing on maintaining function and quality of life. Physical therapy, occupational therapy, orthotic devices (such as ankle-foot orthoses), and pain management are cornerstones of care. Surgical intervention may be considered for severe skeletal deformities. Several subtypes exist within this category, including CMT1A (caused by PMP22 gene duplication), CMT1B (MPZ gene mutations), and others, each with specific genetic causes but overlapping clinical presentations. Research into gene therapy and pharmacological approaches is ongoing.

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