We correlated the weighted genetic risk score measured using 107 established susceptibility variants for multiple sclerosis (MS) with the age at onset in bout-onset (BOMS, n=906) and progressive-onset MS Italian patients (PrMS) (n=544). We observed an opposite relationship in the two disease courses: a higher weighted genetic risk score was associated with an earlier age at onset in BOMS (rho= -0.1; p=5 × 10(-3)) and a later age at onset in PrMS cases (rho=0.07; p=0.15) (p of difference of regression=1.4 × 10(-2)). These findings suggest that established MS risk variants anticipate the onset of the inflammatory phase, while they have no impact on, or even delay, the onset of the progressive phase.
Keywords: Primary-progressive; age of onset; genetic risk; multiple sclerosis; relapsing–remitting; weighted genetic risk score.
© The Author(s), 2014.