Charcot-Marie-Tooth disease type 4E

Charcot-Marie-Tooth disease type 4E (CMT4E), also known as congenital hypomyelinating neuropathy or CMT4E/congenital hypomyelinating neuropathy, is a rare and severe autosomal recessive hereditary motor and sensory neuropathy caused by mutations in the EGR2 (Early Growth Response 2) gene. This gene plays a critical role in peripheral nerve myelination by Schwann cells. CMT4E is characterized by severely impaired myelination of peripheral nerves from birth, leading to profound motor and sensory deficits. It is one of the most severe forms within the CMT4 spectrum of demyelinating neuropathies. Clinical features typically present at birth or in early infancy and include severe generalized hypotonia (floppy infant), marked muscle weakness, areflexia, and respiratory difficulties that may require ventilatory support. Affected individuals often have significantly delayed motor milestones, and many never achieve independent ambulation. Nerve conduction velocities are dramatically reduced, often below 10 m/s, reflecting the severe hypomyelination of peripheral nerves. Additional features may include distal muscle wasting, skeletal deformities such as scoliosis and foot deformities, and cranial nerve involvement leading to facial weakness or feeding difficulties. There is currently no cure or disease-modifying treatment for CMT4E. Management is supportive and multidisciplinary, involving physical therapy, occupational therapy, orthopedic interventions for skeletal complications, and respiratory support as needed. Genetic counseling is recommended for affected families. Research into gene therapy and other molecular approaches for CMT-related neuropathies is ongoing but remains in early stages.

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