People with restless legs syndrome (RLS) typically say they feel pins and needles in their legs, experience sudden compulsions to get up and walk to relieve the discomfort, and at night suffer involuntary leg jerks called periodic limb movement. Skeptics argue it isn抰 really a disease. Now, two independent studies find a link between certain genes and the affliction.
Estimates of prevalence vary widely and with ethnicity: One study found that one in every 1000 people in Singapore has the condition, whereas another claimed that a whopping 15% of Western Europeans may be afflicted. Whatever the rate, symptoms are often worse at night, disrupting sleep and affecting overall well-being. The condition has also been linked to hypertension. However, some skeptics argue that drug companies have hyped the condition, leading to over-diagnosis.
A team led by Juliane Winkelmann at the Institute of Human Genetics and at the Max Planck Institute of Psychiatry, both in Munich, Germany, examined 401 patients whose restless legs run in the family. They analyzed 500,000 one-letter variations, or single nucleotide polymorphisms, in their DNA to look for commonalities. They then confirmed possible culprits in two separate studies of Germans and French-Canadians. Reporting in Nature Genetics, they describe three variants associated with the syndrome. Curiously, the genes are involved in embryonic development. \"We were completely surprised,\" says Winkelmann.
Similarly, a team led by geneticist Hreinn Stefansson at deCODE Genetics, the biopharmaceutical company in Reykjavik, Iceland, analyzed sequences from 17,000 Icelanders, 965 of whom have RLS. They found one gene, BTBD9, which the German study also found: People with it were up to 80% more likely to have the syndrome as those without it. BTBD9 accounts for 50% of cases, the team reports this week in the New England Journal of Medicine. \"The discovery of a gene like this shows it's clearly based in biology,\" says Kari Stefansson, Chief Executive of the company and member of the research team. They also found links to low levels of iron and dopamine.
\"We now are given a hint as to what parts of RLS may be genetically determined,\" says John Winkelman, a sleep specialist at Harvard Medical School in Boston, Massachusetts. Still, he points out that periodic limb movement occurs in other sleep disorders, and he would like to see whether the variants appear in people with such ailments
科学》网络版每日消息称，发表于《自然遗传学》和《新英格兰医学杂志》的多项研究均发现了与不宁腿综合症有关的基因突变。
患有不宁腿综合症的人都会说他们感觉脚发麻，常常突然被迫起身行走使自己感觉舒服些，晚上还会出现一种被称作周期性肢体运动的无意识腿部抽动现象。一些质疑者怀疑这其实不是一种疾病。现在，也有两项独立的研究发现了两种特定基因和这种痛苦现象之间的联系。研究估计这种现象非常普遍，而且带有种族特性：一项研究表明在新加坡每1000人中就有1人存在这种症状，而另一项研究称西欧有15%人群受该病影响。不管比率如何，晚上的症状总是比较严重，影响睡眠和一切的状态。该疾病甚至与高血压有关。不管怎样，一些质疑者称制药公司夸大了疾病现象，为的是诊断更多的病人。在德国慕尼黑的人类基因研究所和Max Planck心理研究所，由Juliane Winkelmann领导的一个研究小组检测了401名家族性不宁腿综合症的患者。为了找出共同特征，他们分析了他们DNA中500，000个单基因突变或者单核苷酸多态性，最终在关于德国人和法籍加拿大人的两个独立的研究中确定了可能的致病突变。该研究结果发表在《自然遗传学》上，他们描述了与综合症有关的三个突变。令人惊讶的是，这些基因与胚胎成熟有关。Winkelmann说，“我们完全被惊呆了”。
同样，这一周《新英格兰医学杂志》也报道了类似的结果。来自冰岛雷基亚比克一家生物药剂公司deCODE Genetics的遗传学家Hreinn Stefansson领导的小组分析了包括965名不宁腿综合症患者在内的17，000名冰岛人的基因序列，最终也发现了与德国研究一致的基因： BTBD9；相比于没有BTBD9的人群，带有该基因的人80%可能会出现不宁腿综合症，BTBD9可以解释50%患者的病因。公司首席执政官兼研究组成员Kari Stefansson说：“BTBD9的发现证实这种疾病有非常明确的生物基础。”他们还发现铁剂和多巴胺水平偏低与该综合症相关。
“关于不宁腿综合症哪个部分是由遗传学决定的，我们现在已经得到一些线索”，来自麻萨诸塞州波士顿哈佛医学中心的睡眠学家John Winkelman说。同时，他还指出其他一些睡眠障碍也会出现周期性肢体运动现象，他很想知道在这些疾病患者中是否也存在同样的突变。 |
发表于 2007-7-25 22:10:56