Apolipoprotein E polymorphism and stroke subtypes in an Italian cohort

Studies have indicated that apolipoprotein E (ApoE)-epsilon4 is a risk factor for ischemic cerebrovascular diseases (ICVD), but the existence of this association is still controversial. The aims of this study were: (1) to compare ApoE genotype and allele frequencies in Italian cases with ICVD and in healthy control subjects and (2) to compare ApoE allele frequencies among ischemic stroke subtypes.

A hospital-based cohort of 302 Italian subjects with ICVD and 228 healthy subjects have been recruited to investigate the role of ApoE polymorphisms as risk factors for ICVD. TOAST criteria were employed to stratify ICVD cases by subtypes.

No significant differences in ApoE genotype and allele frequencies were found between cases and control subjects. The frequency of ApoE-epsilon4 was lower in cases than in control subjects (6% vs. 10.1%), although not significantly. No differences in ApoE genotype and allele frequencies were evident among ICVD subtypes. However, out of 36 ApoE-epsilon4 alleles 23 (3.7%) were found in subjects with ICVD related to primary degenerative arterial disease related to large vessel disease and small vessel disease, and 13 (2.1%) in remaining subjects. Using logistic regression analysis we assessed whether ApoE-epsilon4 allele was independently associated with risk of ICVD related to a primary degenerative arterial disease compared to other ICVD subtypes. While classical risk factors were significantly associated with higher risk for ICVD due to large vessel disease and small vessel disease than other ICVD subtypes, the role of ApoE-epsilon4 allele was not significant (OR 1.25, 95% CI 0.57-2.74).

Our study shows similar ApoE-epsilon4 genotype and allele frequencies in patients with ICVD and in control subjects. No differences were found among different ICVD subtypes either.