Genotypes at the APOE and SCA2 loci do not predict the course of multiple sclerosis in patients of Portuguese origin.

Multiple sclerosis (MS) is a demyelinating disease that affects about one in 500 young Europeans. In order to test the previously proposed influence of the APOE and SCA2 loci on susceptibility to MS, we studied these loci in 243 Portuguese patients and 192 healthy controls and both parents of 92 patients. We did not detect any significant difference when APOE and SCA2 allele frequencies of cases and controls were compared, or when we compared cases with different forms of the disease. Disequilibrium of transmission was tested for both loci in the 92 trios, and we did not observe segregation distortion. To test the influence of the APOE epsilon4 and SCA2 22 CAGs alleles on severity of disease, we compared age at onset and progression rate between groups with and without those alleles. We did not observe an association of the epsilon4 or the 22 CAGs alleles with rate of progression in our total patient population; allele epsilon4 was associated with increased rate of progression of MS in a subset of patients with less than 10 years of the disease. However, globally in the Portuguese population, the APOE and SCA2 genes do not seem to be useful in the clinical context as prognostic markers of this disorder.