MOG antibody-associated disease epidemiology in Olmsted County, USA, and Martinique.

Objectives: To report myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) epidemiology in two American regions using 2023 diagnostic criteria.

Patients And Methods: We compared age- and sex-adjusted incidence and prevalence of MOGAD per 2023 diagnostic criteria in Olmsted County (Minnesota [USA]) and Martinique (Caribbean [FR]) (01/01/2003-12/31/2018, prevalence day) using Poisson regression. Archived sera in 68-85% were available for MOG-IgG testing by live cell-based assay at Mayo Clinic.

Results: Of 21 patients with MOG-IgG positivity identified, 16 fulfilled MOGAD criteria (38% female; median age of 27 years, interquartile-range [IQR 23-42]) and five with low-positive MOG-IgG did not (optic neuritis lacking supportive criteria, 2; alternative diagnosis of multiple sclerosis, 3). MOGAD prevalence was similar in Olmsted County (3.70/100,000, 95% confidence interval [CI] 0.74-6.66]) and Martinique (2.61/100,000; 95% CI 0.85-4.37, P = 0.46). MOGAD incidence was 3.00/million-person-years (95% CI 0.78-5.22) in Olmsted County and 1.18/million-person-years (95% CI 0.30-2.07) in Martinique (P = 0.08). Children represented 29% of MOGAD in Olmsted County and 11% in Martinique. During their disease course the attacks included: optic neuritis (13/16 [81%]); myelitis (6/16 [38%]); and acute disseminated encephalomyelitis (2/16 [13%]). The proportion of MOGAD among incident CNS demyelinating diseases was greater in children (13-14%) than adults (2-4%; P = 0.005). At last follow-up (median, 5 years, IQR 2-9), the median EDSS was 1.0 (IQR 0.5-2.75) with 1/16 (6%) blind in one eye and 9/16 (56%) had relapsing MOGAD.

Conclusions: This study provides estimates of incidence and prevalence of MOGAD in the USA and Martinique and shows that, although children are predisposed, the disease is spread broadly across the age spectrum and population-based outcomes are favorable.