美國一項新研究顯示,，一個被稱為CLU的阿爾茨海默氏癥（早老性癡呆癥）風險基因早在患者發(fā)病前50年就開始損害大腦,。研究人員說，這種損害不會表現(xiàn)出癥狀,，但能通過核磁共振掃描觀察到,。
CLU基因是在2009年與另外兩個阿爾茨海默氏癥風險基因一起被發(fā)現(xiàn)的。當時有研究認為,，攜帶CLU基因的人罹患這種癡呆癥的風險要高16%,，但其作用機制并沒有弄清,。
美國加州大學洛杉磯分校的研究人員在新一期《神經(jīng)科學期刊》網(wǎng)絡上報告說,，CLU基因損害覆蓋在大腦神經(jīng)元外側(cè)起保護作用的髓鞘質(zhì)，使其功能減弱,，最終導致阿爾茨海默氏癥在晚年發(fā)作,。
研究人員表示，攜帶CLU基因的人,，在青少年時期并不會出現(xiàn)認知能力減退,，因為大腦能自動修補。但隨著年齡增長,，自動修補能力減弱,，認知能力就會逐漸減退。
研究人員還發(fā)現(xiàn),，CLU基因并非少數(shù)人才有,，白人攜帶這種基因的比例高達88%。
報告主要撰稿人,、神經(jīng)學教授保羅·湯普森說,，認識這一基因可幫助阿爾茨海默氏癥潛在病人提前50年采取預防措施，包括堅持鍛煉身體及保持健康的飲食習慣等,。（生物谷Bioon.com）
生物谷推薦原文出處：
The Journal of Neuroscience DOI:10.1523/?JNEUROSCI.5794-10.2011
Common Alzheimer's Disease Risk Variant Within the CLU Gene Affects White Matter Microstructure in Young Adults
Meredith N. Braskie1, Neda Jahanshad, Jason L. Stein1, Marina Barysheva, Katie L. McMahon, Greig I. de Zubicaray, Nicholas G. Martin, Margaret J. Wright, John M. Ringman, Arthur W. Toga1, and Paul M. Thompson1
There is a strong genetic risk for late-onset Alzheimer's disease (AD), but so far few gene variants have been identified that reliably contribute to that risk. A newly confirmed genetic risk allele C of the clusterin (CLU) gene variant rs11136000 is carried by ～88% of Caucasians. The C allele confers a 1.16 greater odds of developing late-onset AD than the T allele. AD patients have reductions in regional white matter integrity. We evaluated whether the CLU risk variant was similarly associated with lower white matter integrity in healthy young humans. Evidence of early brain differences would offer a target for intervention decades before symptom onset. We scanned 398 healthy young adults (mean age, 23.6 ± 2.2 years) with diffusion tensor imaging, a variation of magnetic resonance imaging sensitive to white matter integrity in the living brain. We assessed genetic associations using mixed-model regression at each point in the brain to map the profile of these associations with white matter integrity. Each C allele copy of the CLU variant was associated with lower fractional anisotropy—a widely accepted measure of white matter integrity—in multiple brain regions, including several known to degenerate in AD. These regions included the splenium of the corpus callosum, the fornix, cingulum, and superior and inferior longitudinal fasciculi in both brain hemispheres. Young healthy carriers of the CLU gene risk variant showed a distinct profile of lower white matter integrity that may increase vulnerability to developing AD later in life.
