A Study On The Relation Between The Apolipoprotein E Polymorphisms And Traumatic Brain Injury

Objective To determine the relationship between APOE polymorphisms(ε2,ε3,ε4 and promoter polymorphisms) and the patient's condition after traumatic brain injury in a cohort of Chinese patients. Methods Venous blood was collected at the time of admission to determine the APOE genotype and promoter polymorphisms in 110 Chinese patients who presented with traumatic brain injury.The APOE polymorphisms (ε2,ε3,ε4 and promoter polymorphisms) were determined by PCR-RFLP.X2 test and logistic regression analyses were performed by SPSS version 11.5. Results 1. In 110 Chinese patients,the distributions of APOE genotypes and alleles matched Hardy-Weinberg Law. 7 of 17 patients with APOEε4(41.2%)had a deteriorated condition(such as larger hematoma than on admission,delayed hematoma, etc.)which was significantly different from those without APOEε4(12 of 93 patients,12.9%,p =0.01).However,neither the presence of ε2 nor of ε3 was significantly different from those absent of it(p>0.05) .logistic regression analyses showed that APOEε4 was a risk factor(OR=4.836,P=0.011,95%CI 1.443 -16.208) to predispose to aggravation after adjusting for patient age ,injury severity and injury mechanism etc.. 2. No differences in APOE promoter genotypic distribution were observed in patient's condition (p>0.05).But after adjusting for patient age ,injury severity and injury mechanism etc.,logistic regression analyses showed that -491AA was a risk facto(rOR=11.681,P=0.009,95%CI 1.824-74.790)as APOEε4. traumatic condition and alcohol-drinking were also risk factor. Conclusions Our findings suggest that the patients with APOEε4 predispose to aggravation after head injury .And in the Chinese population ,only APOE -491 promoter alleles confer significant risk factor of brain injury,but not independent risk factor.This may contribute to the poor outcome after head injury.