Objective: The apolipoprotein E (APOE) polymorphism is known to impact on various neurologic disorders and has differential effects on the immune system and on CNS repair. Previous findings concerning a possible modulation of the clinical course of MS have been inconsistent, however.
Methods: In a cross-sectional study, the authors investigated 374 patients with clinically definite MS and a disease duration of at least 3 years and related their clinical and demographic findings to the allelic polymorphism of the APOE gene. The genotype distribution of patients with MS was compared with a cohort of 389 asymptomatic, randomly selected elderly volunteers.
Results: The authors found no significant differences in the distribution of genotypes between patients with MS and controls. However, patients with MS with the epsilon4 allele (n = 85) had a significantly higher progression index of disability (0.46 +/- 0.4 versus 0.33 +/- 0.26; p < 0.004) and a worse ranked MS severity score (5.1 +/- 1.9 versus 5.7 +/- 1.7; p = 0.05) than their non-epsilon4 counterparts, despite significantly more frequent long-term immunotherapy in epsilon4 carriers (74% versus 58%; p < 0.007). The annual relapse rate in epsilon4 carriers (0.87 +/- 0.56) was significantly higher than in patients with MS without an epsilon4 allele (0.71 +/- 0.47; p = 0.03).
Conclusions: These results suggest no effect of the APOE genotype on susceptibility to MS, but indicate an association of the APOE epsilon4 allele with a more severe course of the disease.