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【bio-news】科学家发现新的基因变异 携带者患心
据英国广播公司1月19日报道，科学家发现一种新的基因变异，它可以在很大程度上增加携带者患心脏病的几率。印度次大陆4%的人是这种基因变异的携带者。
英国维康信托基金会桑格研究所在印度城市海德拉巴和英国都有分支。该研究所的科学家发现了这一新的基因变异。
心脏病的起因多种多样，其中也包括生活方式。科学家说，可能有一大批遗传基因都会影响携带者患心脏病的几率。
但是，桑格研究所发现的这种心脏蛋白基因变异不同寻常。其一是因为携带者人数众多，其二则是因为它影响巨大。
携带变异基因的人到了中年晚期患心脏病的机会大大增加，可以高达90%。
另外非常不寻常的一个现象是，这个基因变异特别集中于一个地区。
参加研究工作的科学家之一泰勒·史密斯说，研究人员收集了来自印度、巴基斯坦、斯里兰卡的数据，他们发现，总体来说，该地区有4%的人携带这种变异基因。
次大陆地区心脏病的发病率近年来急剧上升。有预测显示，到2010年，印度心脏病患者将占世界患者总数的60%。
个中原因可能包括生活方式，比如抽烟、缺乏锻炼、饮食结构不良等。但是，潜在的基因因素也不容忽视。
现在科学家已经发现了一种可以预警的基因变异，下一步就是要找到一种可以筛选出携带者的检测手段。
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Asian heart disease gene found
http://news.***.co.uk/2/hi/health/7833753.stm
A gene mutation that almost guarantees the development of heart disease is carried by 60m people, researchers say.
Around 4% people from the Indian subcontinent have the mutation, which increases the risk of heart disease seven-fold, Nature Genetics reports.
It is rare to find a gene which has such a big effect and is so common, the international team of scientists said.
Experts said it could lead to a screening test but it was not yet clear if it would aid treatment decisions.
Heart disease is the number one killer in the world and India is particularly badly hit, with the problem set to intensify in coming years.
The World Health Organization estimates that by 2010, India will have 60% of the world's heart patients.
The researchers first identified the mutation in the heart protein gene MYBPC3 five years ago in two Indian families with cardiomyopathy - a disease causing deterioration of the heart muscle.
In the latest study they looked for the mutation in 800 people with heart disease and 700 controls.
They found the mutation was common - carried by 1% of the world's population.
And the increased risk of heart disease - seven times that of people without the mutation - is so high is almost guarantees the development of heart problems.
Abnormal protein
In the test tube, cells with the mutation - where 25 letters of genetic code are missing - the MYBPC3 protein is abnormal and "messes up" the structure of the heart muscle.
The researchers said in younger people the body seemed to have an effective mechanism for breaking down and removing the mutated protein.
But with age the mechanism stops working efficiently which is why heart disease in people carrying the gene develops in middle age.
Chris Tyler-Smith, a senior investigator at The Wellcome Trust Sanger Institute, Hinxton, UK, and one of the study authors said the mutation probably arose around 30,000 years ago and has been able to spread because its effects usually develop only after people have had their children.
"What we expect to find are common mutations with very small effects or rare mutations with big effects.
"The combination of big effects and high frequency is surprising."
He said "in principle" it would be extremely easy to test people at a young age for the gene but at the moment all that doctors could do would be to offer healthy lifestyle advice.
"In the longer term I think trying to improve the efficiency of the protein degradation mechanism might be a novel approach for treatment - all you would have to do is postpone the effects for a few decades."
Professor Peter Weissberg, medical director at the British Heart Foundation, said the study underpins the strong genetic nature of heart disease.
"It provides good grounds for screening people of South Asian origin with unexplained heart failure and screening their families if positive."
"However, there is no evidence yet that early detection will lead to improved outcome since we have no idea if the outlook for this group can be modified by conventional heart failure treatments." [标签:content1][标签:content2]
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作者:admin@医学,生命科学 2011-02-15 05:12
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