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都是粒腺体的错！？
高血压伴随了其它心血管危险因子，如血液中高胆固醇和三酸甘油酯含量，以及糖尿病。虽然肥胖的人常会有这些代谢并发症状，可是体重正常人也会有，所以过重并非主因。
耶鲁大学医学院的Richard Lifton等人发现了一位血液中镁离子含量过低的女病人，接着他们发现粒线体中一连串的基因突变是主因。这位女病人的其它亲人也有低镁离子的症状。追踪了142个亲人，他们大多有低镁离子、高血压和高胆固醇的问题。这些症状都是遗传自一位母亲－－粒线体靠母系遗传把突变传给了一大票后代。
把整个粒线体定序了之后，他们发现一个碱基的变化发生在tRNA的基因中，一个胸腺嘧啶变成了胞嘧啶，结果改变了tRNA的结构而影响了蛋白质合成。
旧金山加州大学的高血压专家Theodore Kurtz指出，虽然还不知道为何这个粒腺体突变会造成多种症状，不过这个发现是非常重要的。之前没前个心脏病学家把粒腺体原来在高血压以及其它心血管疾病危险因子上参了一脚，不过这个发现将改变一切。
原学术论文：Science, Published online 21 October 2004. DOI: 10.1126/science.1102521
--参考来源：
• EurekAlert! (10/21/2004) -- Mitochondrial mutation linked to blood pressure and choleste
• ScienceNOW (10/21/2004) -- When Mitochondrial Genes Go Bad Mitochondrial mutation linked to blood pressure and cholesterol problems
New Haven, Conn. ?Researchers at Yale and Syracuse Universities found the first direct evidence for a mutation in mitochondrial DNA that directly affects blood pressure and cholesterol levels.
It has long been known that several metabolic traits including high cholesterol and hypertension cluster in individuals more frequently than by chance, but the underlying causes were unknown. This study, published early in Science Express on line, suggests that altered mitochondria may account for the clustering as well as the disorders.
"Looking further, this finding raises the possibility that all features of the metabolic syndrome may be attributable to altered mitochondrial function," said Richard P. Lifton, Sterling Professor and Chair of Genetics at Yale and research team leader.
Metabolic syndrome is an emerging problem in industrial societies and. epidemic in the United States. The symptoms include high blood pressure, cholesterol and triglycerides, insulin resistance, obesity, and low HDL. There is independent evidence that altered mitochondrial function plays a role in insulin resistance and high triglyceride level, and the current finding indicates that these other components of metabolic syndrome may also linked to mitochondrial disfunction.
The clear correlation of mutation and disorder in this study was made possible by the evaluation of 142 people in four generations of an affected family. Although family members with each disorder ?hypertension, hypercholesterolemia and hypermagnesemia ?have the same mitochondrial mutation, the presence of the mutation does not produce all of the symptoms in each individual.
While this study focuses on a rare mutation in mitochondria that provides a clear link to specific disorders, mitochondrial function is known to decline with age in normal people and may be contributing to these common traits in the general population.
Other researchers included Frederick H. Wilson, Ali Hariri, Anita Farhi, Hongyu Zhao, Kitt Falk Petersen, Hakan R. Toka, Carlo Nelson-Williams, Michael Kashgarian, and Gerald I. Schulman at Yale, and Khalid M. Raja and Steven J. Scheinman at Syracuse University. Grants from the National Institutes of Health the Howard Hughes Medical Institute and the American Heart Association supported this research. 阿滋海默症（Alzheimer's Disease）具有家族性，但目前已知并不是一种遗传疾病。确切的阿滋海默症成因至今仍不清楚。最新的研究显示阿滋海默症可能跟粒线体的突变有关。
研究人员至今已经发现某些和「家族性阿滋海默症」有关的基因，然而这些特殊基因对「晚发性阿滋海默症」的影响仍然没有重要的关联。加州大学尔湾分校（University of California, Irvine）的Douglas Wallace 及其同仁发现，粒线体内DNA 的突变可能是导致晚发性阿滋海默症的起因。研究人员发现，在比较四十个年龄相当的正常人和二十三个阿滋海默症病人的脑部检体后发现，有65% 的阿滋海默症的病人在脑部调控粒腺体基因表现的DNA上有突变。研究人员同时发现，早期发生的脑部基因突变会导致大量细胞携带突变基因，并可能是导致某些阿滋海默症患者较早死亡的原因。
哈佛医学院神经遗传学家Rudolph Tanzi表示，虽然这个研究令人瞩目，但是由于样本数量过于狭小，而且基因突变的比例（65%）并不是很高，所以晚发性阿滋海默症和此粒腺体基因突变的真正关系仍待进一步的研究。
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作者:admin@医学,生命科学 2010-11-23 17:11
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