Association study between ApoE genetic polymorphism and vascular dementia after cerebral infarction

Objective To study the distribution of ApoE genetic polymorphism and its influence on the latency and severity of vascular dementia after cerebral infarction. Methods Hachinski Inchemic Score Test and Mini Mental State Examination (MMSE) were performed to test the frontotemporal cerebral infarction patients. Those with Hachinski ≥ 7 and MMSE ≤ 24 were recruited in the VD group. Meanwhile, the healthy controls were included. The intervals from first episode of cerebral infarction to first diagnosis of VD were obtained and considered as the latency. MMSE scores were used as the index of severity. Blood samples from all subjects were collected for ApoE genetic polymorphism test by PCR. Chi-square test was used to compare the distributions of ApoE genetic polymorphism and student t-test was performed to analyze the difference of latency and MMSE scores between the VD group and the control group. Results The VD group had obviously higher ε4 allele frequency (30.38%, 48/158) and ε4 genotype frequency (45.57%, 36/79) as compared to those of the control group (15.62%, 25/160; 28.75%, 23/80) (P=0.002 and 0.028). ApoE ε3 allele frequency (60.76%, 96/158) and ε3 genotype frequency (45.57%, 36/79) were significant lower in the VD group as compared with the control group (77.50%, 124/160; 61.25%, 49/80, P=0.001 and 0.047). No significant difference was observed in ε2 allele and genotype frequency between the two groups. VD patients with ε4 genotype had an obviously shorter mean latency after first-onset of cerebral infarction[(13.44±6.00) months] as compared with ε2 genotype[(22.43±9.01) months] (P=0.003). However, there was no significant difference in the severity of VD among three genotypes (P>0.05). Conclusion ApoE ε4 genotype may be associated with the susceptibility of VD and it may shorten the latency of VD after cerebral infarction.