Prevalence of multiple sclerosis in Verona, Italy: an epidemiological and genetic study

Background and purpose Recent multiple sclerosis (MS) prevalence studies classify Italy as a high-risk area without intra-regional latitude effect. Objectives To determine MS prevalence in Verona, Italy, and frequency of myelin oligodendrocyte glycoprotein (MOG) gene G511C polymorphism and HLA-DRB1*15 locus in a sample of cases and healthy controls. Methods The study area population on the prevalence date (31 December 2001) was 253208 (133508 women, 119700 men). Multiple case sources were examined. Patients fulfilling McDonald's criteria (2001) were included. Crude, age- and sex-specific prevalence rates were computed. MOG G511C polymorphism and HLA-DRB1*15 were determined by standard methods. Results We identified 270 cases of MS yielding a crude prevalence rate of 106.6/100000 (95% CI: 94120). Prevalence was higher in women (140.8/100000) than in men (68.5/100000). The age-adjusted prevalence rate standardized to the European population was 96.0/100000. MOG G511C polymorphism did not differ between cases and controls. HLA-DRB1*15 frequency was 58/155 (37%) in cases and 24/157 (15%) in controls (P<0.001). There was no HLA-DRB1*15 influence on susceptibility to other autoimmune disorders. Conclusions The high MS prevalence in Verona confirms Italy as a high-risk area with a homogenous distribution across the country. HLA-DRB1*15 is a relevant MS susceptibility locus in the Italian population, possibly with little influence on the occurrence of concomitant autoimmune disorders.