Anti–MAG Antibodies

This laboratory assay detects IgM subclass autoantibodies against myelin-associated glycoprotein (MAG). MAG is an integral component of the myelin sheath produced by Schwann cells in the peripheral nervous system. It plays an essential role in maintaining the stability and function of myelinated nerves, enabling rapid and precise nerve impulse conduction. Anti-MAG IgM antibodies interfere with normal myelin function, leading to progressive demyelination of peripheral nerves and a chronic, slowly progressive neuropathy with predominantly sensory symptoms.

Clinically, anti-MAG neuropathy features tingling, numbness, hand tremor, gait difficulty and muscle weakness, mainly affecting distal extremities (hands and feet) with gradual worsening over time. The condition is often associated with IgM monoclonal gammopathy. Diagnosis is based on clinical evaluation, supported by electrodiagnostic studies (electromyography and nerve-conduction velocities) and detection of anti-MAG antibodies in blood, frequently alongside identification of an underlying monoclonal gammopathy. Early diagnosis and targeted treatment can significantly improve quality of life. Management may include immunosuppressive therapies and symptomatic measures to improve motor and sensory function.