Epidemiology of autoimmune neurologic disorders in Sardinia: Comparison between NMOSD and Myasthenia Gravis

Over the last two decades, the spectrum of neurologic disorders associated with specific autoantibody biomarkers have expanded. These autoimmune disorders may affect both the central and peripheral nervous system, including the neuromuscular junction. Aquapoin-4-IgG-positive neuromyelitis optica spectrum disorder (AQP4-IgG+NMOSD) and myasthenia gravis (MG) are among the most common autoimmune neurologic disorders of the central and peripheral nervous system, respectively. Although epidemiological studies are crucial to better understand the burden of these rare diseases in the population and adequately plan healthcare assistance, data on incidence and prevalence of autoimmune neurologic disorders in Italy are scarce and outdated. Among Italian regions, Sardinia has historically been studied for its unique characteristics with an unusually high prevalence of different immune-mediated disorders, including multiple sclerosis; but data on antibody mediated neurologic disorders are lacking. The aim of this thesis was to investigate the incidence and prevalence of AQP4-IgG+NMOSD and MG in the island of Sardinia. We found that, while the incidence and prevalence of AQP4-IgG+NMOSD is in line with that of other countries with a predominantly White population, the incidence and prevalence of MG in Sardinia are disproportionally high compared to what previously reported in the literature. In particular, the prevalence of MG in Sardinia seems to exceed the established European threshold to define a rare disorder. Our data represent the first step for an extensive assessment and comparison of the epidemiology of different autoimmune neurologic disorders in Sardinia, which might help better understand the risk factors associated with each disorder and help planning healthcare resources and treatment strategies.