C5 and myasthenia gravis: The anti-C5 (mAb) eculizumab, already in the clinic for more than 16 years for the treatment of rare systemic complement dysregulation diseases, was FDA approved for the treatment of the neuromuscular conduction disorder myasthenia gravis (MG) in 2017 and for the demyelinating disease NMO spectrum disorder (NMOSD) in 2019 [219,220].