丹麥科學家最新研究發(fā)現(xiàn),，一種影響鐵代謝的普通基因變異后,，可使其攜帶者患中風的風險大大上升。
據(jù)英國《新科學家》雜志網(wǎng)絡版3月27日報道,，丹麥海萊烏大學醫(yī)院的研究人員發(fā)現(xiàn),，這種名為ＨＦＥ的基因一旦發(fā)生被稱為Ｈ６３Ｄ突變的細微變異,，就會導致變異基因攜帶者血液中的鐵元素過量進入細胞，由于這種現(xiàn)象通常不易發(fā)現(xiàn),，有些這種基因變異的人還會因此患上肝硬化,。
為了研究這種基因變異是否對神經(jīng)系統(tǒng)有影響，研究人員在丹麥收集了9000人的ＤＮＡ樣本,，然后跟蹤這些人的健康情況長達24年,。這期間約有400名參與者出現(xiàn)過大腦缺血性卒中。ＨＦＥ基因變異后會出現(xiàn)不同版本,。在156名攜帶兩個ＨＦＥ基因變異版本的參與者中,，有１０％在研究期間死于這種中風。相比較,，攜帶一個變異版本或不攜帶變異版本的參與者中,，只有４％死于中風。
研究人員在考慮如年齡,、性別和膽固醇水平等因素后推算出,，攜帶兩個ＨＦＥ基因變異版本的人患中風的風險比不攜帶者高１８０％。
這項研究的負責人推測,，這種基因發(fā)生Ｈ６３Ｄ突變,，會使血液中的鐵元素過量進入細胞，有可能加快血管內(nèi)危險血凝塊的形成,，從而使大腦血液循環(huán)中斷,。不過這一研究還沒有發(fā)現(xiàn)Ｈ６３Ｄ突變與血管內(nèi)血凝塊形成之間有任何關系。
研究人員認為,，對Ｈ６３Ｄ突變進行基因測試有助于發(fā)現(xiàn)中風風險較高的人,，這些人可及時服用藥物如他汀類藥物或阿斯匹林，以降低出現(xiàn)血凝塊的風險,。
英文原文：
Common gene mutation linked to tripled stroke risk
12:05 27 March 2007 NewScientist.com news service Roxanne Khamsi
People with a common gene mutation that affects iron metabolism are nearly three times more likely to suffer stroke, a new study reports. The finding should help doctors identify patients who are most at risk of stroke, enabling them to take preventative measures, the researchers say.
As many as one in four Europeans carry one defective copy of this gene, called HFE. Borge Nordestgaard at Herlev University Hospital in Copenhagen, Denmark, explains that a tiny change in the HFE gene, known as the H63D defect, appears to cause excessive iron uptake from the blood into cells. He adds that while this iron overload usually goes undetected, some people may develop liver cirrhosis late in life as a result.
To see whether this gene had an effect on the nervous system, Nordestgaard and colleagues collected DNA samples from 9000 people in Denmark, and then tracked their health over the course of 24 years. During that period about 400 participants suffered an ischemic stroke – a sudden loss of blood supply to a region of the brain.
Ten per cent of the 156 subjects with two copies of the defective HFE gene died from this type of stroke during the study. By comparison only 4% of people with one or no mutated versions of HFE died from stroke. After adjusting for possible confounding factors such as age, gender and cholesterol levels, researchers calculated that people with two mutated HFE genes had a 180% higher risk of stroke than those with no mutations in the gene.
Missing plaques
Nordestgaard says he expected that the iron overload associated with the H63D mutation may somehow increase the formation of dangerous plaques inside blood vessels, thereby disrupting circulation in the brain. But his team did not find any link between the H63D mutation and symptoms of plaque build-up in the subjects.
"Further research is needed to determine why this gene appears to cause such a significant increased risk of stroke, since our data suggests plaque build-up in the arteries and iron overload are not to blame," he says.
He says that a gene test for the H63D mutation could help encourage patients with stroke risk factors to take drugs such as statins or aspirin to reduce the risk of blood clotting. "If people are told they have a genetic risk they might better stick to their preventative medication."
Daniel Woo at the University of Cincinnati in Ohio, US, says that further research into how the H63D mutation and other gene defects prime the brain for stroke could eventually help drug developers find targets for new preventative medicines.
Journal reference: Neurology (vol 68, p 1025)
