The Prevalence, Demographics, Clinical Features, Neuroimaging, and Inter-ethnic Differences of MOGAD in Malaysia with Global Perspectives.

Introduction: CNS IIDDs tested positive for anti-MOG are known to have a distinct clinical profile with a better overall prognosis.

Objectives: We aim to determine the prevalence, demographic and clinical characteristics of MOG antibody disease (MOGAD) specifically identifying any ethnic variations unique to our local population, with global perspectives.

Methods: This is a cross-sectional study conducted at the Neurology Department, Kuala Lumpur Hospital from January 2018 to January 2021. Out of 750 CNS IIDDs, seventy-eight consecutive anti-AQP4 antibody negative NMOSD/high risk undifferentiated relapsing or monophasic CNSIIDD subjects were tested for anti-MOG.

Results: Anti-MOG was positive in thirty six out of seventy-eight (%)(46.1%) seronegative patients. The prevalence of MOGAD in our Malaysian population is 0.12 per 100,000 persons with less marked female preponderance of 2:1 and younger age at onset of 23.8 ± 14.4 years. Despite a predominantly ethnic Malay population, a high proportion of our MOGAD patients were Indian (Proportion of Malay:Chinese:Indian:others; 16:9:10:1, prevalence 0.5 per 100,000 population for Indians) with favourable disease course in the most with minor exceptions. Monophasic and relapsing disease course was seen in 11.2% and 88.8% of patients respectively. However, fulminant aggressive disease can occur especially amongst the Chinese and paediatric cohorts. Optic neuritis, NMOSD and ADEM were the commonest presentations at onset and first relapse. EDSS at diagnosis, first relapse, and last follow-up were 4.5±2.5, 3±2.0, and 1.75(range 1-3). Neuroimaging showed large, fluffy, PRES- like supratentorial cortical, periventricular deep white matter ,diencephalon lesions,enhancing anterior optic nerve with or without chiasmal sparring lesions and cervical/cervicothoracic involvement. Area post rema lesions were rare. Threshold steroid levels exist relapsing on withdrawal some fulminantly requiring Immunosuppressants(rituximab) and intravenous immunoglobulins to maintain remission.

Conclusion: Malaysian MOGAD profile was similar to its international descriptions of the disease with ethnic selectivity for Indians. Prolonged steroid maintenance is essential to prevent relapses. Fulminant aggressive cases of MOGAD especially amongst Paediatric patients and the Chinese cohort have been reported.