The Role of Genetics in TBI Recovery
Friedman, G., Froom, P., Sazbon, L., Grinblatt, I., Shochina, M., Tsenter, J., Babaey, S., Yehuda, B., & Groswasser, Z. (1999). Apolipoprotein E-e4 genotype predicts a poor outcome in survivors of traumatic brain injury. Neurology, 52, 244-248.
The prognosis of recovery following traumatic brain injury (TBI) has involved factors including age and estimated damage, however genetic factors may also play a role. A gene responsible for the productions of apolipoprotein E (ApoE-e4) may influence the brain's susceptibility to brain injury and the capacity for repair and regeneration, also predicting outcome. The purpose of this study was to determine whether APOE genotypes "predict days of unconsciousness and a suboptimal functional outcome in TBI survivors"(p.244). The authors hypothesized that the ApoE-e4 allele would be present in those who were unconscious for at least 7 days and had unsatisfactorily recovery.
In this study, analysis was performed on 69 patients who had experienced blunt head injuries, ranging from ages 18 to 73 years. "The ability to obey commands was the operational definition of the end of coma" in which a message was "received, understood, and acted on" by the patient (p.245). A functional assessment of mobility and independence in activities of daily living was performed after a 6-8 month follow-up period. Good functional outcome was defined as having no dysarthria or dysphasia, being independent and having no severe cognitive or behavioral abnormalities. Unfavorable outcome included fully dependent patients or those who had severe cognitive abnormalities.
The results of the study showed:
- 27 subjects with at least one allele of e4
- all poorer outcomes except for the presence of epilepsy were more frequent in those with the e4 allel
- one of the 27 subjects with the e4 allele had excellent function compared to the 13 of 42 without the e4 allele
- those with unfavorable outcomes were distributed evenly between those with and those without the e4 allele (p.246).
The results indicated that the e4 allele predicted short and long-term morbidity. Data confirmed the association between the ApoE-e4 allele and outcome in patients with TBI, implying genetic susceptibility. Data confirms the implication of genetic susceptibility showing a relation between the ApoE-e4 allele and outcome in TBI patients.
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