Genetic Variation of ApoE Gene in Ethnic Kashmiri Population and Its Association with Outcome After Traumatic Brain Injury

Abstract

The outcome from traumatic brain injury (TBI) is variable and only partly explained by known prognostic factors. Genetic factors may influence the brain's susceptibility to injury or capacity for repair and regeneration. ApoE has been implicated in modifying neurological outcome after TBI, although the mechanisms by which this occurs remain poorly defined. Apolipoprotein E is an apparently multifunctional protein involved in the response of the brain to injury and in subsequent repair processes. Several studies have shown that patients with APOE e4 have a poorer outcome after TBI. This study was aimed to analyse the genotypes of ApoE in Kashmiri population and to examine the association of APOE genotype with outcome after TBI. A total of 450 subjects (300 healthy controls and 150 TBI patients) were recruited for the study. Genotyping was done by PCR-restriction fragment length polymorphism (RFLP).Our study indicated Apoe3/e3 to be the most common genotype in this study group. The allele frequency of the Apo E gene in these study subjects was observed to be 0.07 for the e2 allele, 0.82 for the e3 allele and 0.11 for the e4 allele. However, no association between the presence of APOe4 allele and outcome after head injury was observed in this study [p = 0.92]. Thus, genotype containing the e4 allele (e4/e3 and e4/e4) was not associated with unfavourable outcome after TBI in Kashmiri population.

ApoE gene polymorphism and its relationship with coronary artery disease in ethnic Kashmiri population

“…This is for the first time that study of ApoE gene polymorphism in CAD patients has been done in ethnically discrete Kashmiri population. Different populations exhibit different frequencies in the distribution of apo E isoforms, and so far, the most frequent allele in all populations examined including our population is e3 which codes for the isoform apo e3 [13,15,16]. In our investigation, ApoE allelic frequencies in CAD group were 0.72, 0.20, and 0.065 for e3, e4, and e2, respectively, while in controls the frequency was 0.82 for e3, 0.11 for e4, and 0.075 for e2.…”

“…Indian population showed the frequency of e3 allele to be higher than e2 and e4 [14]. Our previous study also reported e3 allele to be the most common allele in Kashmiri Population [15]. This study was carried out to determine the role of ApoE genotypes in the risk of CAD in Kashmiri population.…”

The Association Between Apolipoprotein E and Functional Outcome After Traumatic Brain Injury

“…We then excluded 2 more studies because they used overlapping or duplicate data, 16 , 17 resulting in 12 studies that met the eligibility criteria and were included in our analyses. 18 – 29 …”

The genetic basis of inter-individual variation in recovery from traumatic brain injury

“…Merritt et al found that the ApoE4 genotype was associated with high levels of psychiatric distress in veterans 75 . Interestingly, the lack of association of ApoE4 genotype with outcomes has been shown in different populations such as African, British, and Indian [76][77][78] . Future studies will need to look closely at how genetic background modulates the effect of ApoE4 genotype of individual response, as recently noted in a study in mice 79 .…”