The E4 gene variant of apolipoprotein E (ApoE) confers an increased risk of developing Alzheimer’s disease, but the mechanisms by which it does so are not understood. ApoE plays a role in transporting fatty molecules to cell membranes, and may be critical for repairing damaged cells. One theory is that the E4 variant is not as effective in performing this healing function, and may predispose a person to neurodegenerative disorders such as Alzheimer’s. Support for this idea now comes from a study published in the February issue of Neurology, which reports that the E4 allele leads to a poorer prognosis for recovery from traumatic brain injuries. In the study, 69 people who suffered blunt head injuries were evaluated for six to eight months by researchers in Israel. Survivors who did not recover well-i.e., were unable to live independently and had severe cognitive or behavioral impairments-were 5.6 times more likely to have the ApoE4 gene than those who did recover well, according to study author Zeev Groswasser of Tel Aviv University. Only one of the 27 study participants with the ApoE4 gene had an excellent recovery, compared to 13 of the 42 participants without the E4 gene. Those with the E4 gene were also more likely to remain unconscious following the brain injury for more than seven days. Groswasser said methods need to be developed to treat people with ApoE4 to improve the cell repair ability. "Also more effective treatments need to be developed for such patients during recovery from traumatic brain injury," he said. "This could include gene therapy, which could perhaps prevent development of Alzheimer's disease."—June Kinoshita
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- Friedman G, Froom P, Sazbon L, Grinblatt I, Shochina M, Tsenter J, Babaey S, Yehuda B, Groswasser Z. Apolipoprotein E-epsilon4 genotype predicts a poor outcome in survivors of traumatic brain injury. Neurology. 1999 Jan 15;52(2):244-8. PubMed.