MUSK and myasthenia gravis: Among excluded individuals (n = 135) based on the exclusion criteria, 80 tested positive for AchR Abs, 9 for Musk Abs, 1 for LRP4 Abs, 24 were seronegative and/or antibody profile was unclear (several diagnoses was established even more than 3 decades before), 6 had congenital MG and 5 had indefinite diagnosis (not laboratory confirmed, with high clinical suspicion – treated as MG).