MOG and myeloid sarcoma: With a MOG seropositivity in 100% of MOGAD patients and 35.4% of MS patients being positive MRZR in our cohort, the estimated population-based prevalence of MOG seropositivity is more than 33x less frequent than a positive MRZR (2/100.000 vs. 67.3/100.000, p<0.00001) (Supplementary Table 11).