An investigation of human apolipoprotein E polymorphisms in multiple sclerosis patients of Iran
Multiple sclerosis (MS) is a chronic inflammatory disorder of the central nervous system, with a complex etiology that includes a strong genetic component. The chromosome 19q13 region surrounding the apolipoprotein E (APOE) gene has shown consistent evidence of involvement in MS. In a cross-sectional study, to show the APOE genotype and allele frequency in the MS population of Iran in comparison with the control group, we genotyped its polymorphisms (?2, ?3 and ?4 alleles). The authors investigated 81 patients with clinically definite MS and 93 asymptomatic elderly volunteers. The frequency of the APOE allele in the MS population in comparison with controls was 9.3% vs. 0.5% for ?4, 44.4% vs. 51.6% for ?3, and 46.3% vs. 47.8% for ?2. The highest frequency of APOE genotype was from ?2/?3 with 66.7% vs. 94.6% and the lowest, ?4/?4 genotype with 2.5% vs. 0%. The authors found significant differences in the distribution of ?4 allele between patients with MS and controls (9.3% vs. 0.5%; ?2=15.2; df=2; p<0.001). The highest frequency of ?4 allele in MS patients was in Pure Turkish (25.0% vs. 5.3%) ethnicity. There was no significant relation between ethnicity and genotype. In the present study ?2/?4, ?3/?4 and ?4/?4 genotypes were more common in bout-onset cases compared to primary progressive cases, and the secondary progressive disease was higher in carriers of ?4 allele. Also, the ?2 allele was higher in relapsing remitting disease.