MMN is a rare immune-mediated motor neuropathy, which presents as slowly progressive, asymmetric, and predominantly distal limb weakness. Weakness typically begins in the fingers or thumb and may include involuntary fasciculations and cramping. As the disease advances, patients may experience wrist drop, foot drop, and/or loss of grip strength, and weakness may move proximally. MMN affects nearly 3x more men than women Years 20 to 70. Mean age onset of 40 years.