Scientists Discover Gene Responsible for Multiple Sclerosis
From VOA Learning English, this is the Health and Lifestyle report.
An estimated two million people around the world have multiple sclerosis, a disease commonly called MS.
The disease can affect a person's brain, spinal cord, and optic nerves in the eyes. It can cause problems with eyesight, balance, muscle control, and other body functions. The severity often differs from one MS patient to the next.
The most severe form of the disease is called "primary progressive." Scientists have found that a single change in a person's genetic material can cause primary progressive MS. They say this finding could lead to a cure for a disease that cripples millions of people.
Researchers have long suspected that multiple sclerosis resulted from some kind of interaction among genes.
Individuals with that genetic interaction, they thought, were more likely than others to get sick. They also believed that something in the environment, such as a viral infection or lack of vitamins in the diet, could activate the disease.
But Canadian researchers have found that is not the cause of the most severe form of multiple sclerosis. With primary progressive MS, a single mutated gene can greatly increase the risk for developing the disease.
This single gene is called NR1H3.
The Canadian researchers are with the University of British Columbia in Vancouver. They reported the findings in the journal Neuron.
The researchers examined medical records for 2,000 Canadian families with family members who had MS. The investigation led them to two families that carried a mutation, a structural change, in the NR1H3 gene. Members of those families suffered from the most severe form of multiple sclerosis.
Medical geneticist Carles Vilari?o-Güell was the lead writer of the report. He noted that 15 to 20 percent of MS cases were thought to be hereditary, but that has never been proven.
Vilari?o-Güell says other studies have linked other genes to the disease. But those genes increased the risk of getting MS by, at most, three percent.
"With this mutation, your risk is 60- to 70-percent. So, that's a 600 to 700 (percent) increase in comparison to the general population. And that's what really makes this completely different from other genetic findings."
In other experiments, the researchers examined the NR1H3 gene in mice. Animals with a normal copy of the gene developed neurological problems when the gene was removed. The problems included a decrease in the production of myelin.
Myelin protects protein on the outside of neurons. It speeds the electrical messages that control movement. A common sign of MS is muscle weakness and a loss of coordination.
Many research teams are studying how to repair myelin in MS patients. Currently, drugs to treat it only slow down progression of the disease. They do not cure it.
Discovery of a single genetic defect as the cause of MS, Vilari?o-Güell says, could mean it may one day be possible to repair the gene. This means curing the crippling disorder.
"You know, the more understanding we have of the mechanism of disease for all these families allows us to develop different treatments for different forms of the disease."
Researchers say they will continue their search for a single genetic cause for the most common form of multiple sclerosis, called "relapsing remitting MS."
They say their hope is that a cure could be discovered soon.
I'm Anna Matteo.
1.body function 身体机能
Love every cell that makes your body function.
2.get sick 生病
How often do you get sick in one year?
3.in comparison to 与...相比
In comparison to city life, life in the country is quiet and peaceful .
4.suffered from 遭受；承受
I merely told him that I suffered from nightmares.
1.They say this finding could lead to a cure for a disease that cripples millions of people.
lead to 导致；造成
Exposure to the air will lead to erroneous results.
Blindly copying others might very well lead to losses.
2.They also believed that something in the environment, such as a viral infection or lack of vitamins in the diet, could activate the disease.
lack of 缺少；缺乏
Production has come to a halt owing to the lack of raw materials.
The whole operation was hamstrung by for lack of funds.
此疾病会影响大脑、脊髓及眼部的视神经 。还会引起视力、平衡、肌肉控制障碍以及其他身体机能问题 。每个MS患者的患病程度均有所不同 。
最严重的程度称为“原发进展型” 。科学家已经发现，人类基因的单一改变会引发原发型MS 。他们表示此项发现将有助治愈数百万患者 。
他们认为，基因进行交互作用的人更容易患病 。他们还相信，病毒性感染或饮食中缺乏维生素等环境因素都会诱发这一病症 。
然而，加拿大研究人员发现，最严重的多发性硬化症并非由此造成 。单个的基因突变会大大增加原发进展型MS的发病风险 。
加拿大研究人员与温哥华英属哥伦比亚大学的人员共同研究 。他们在《神经元》期刊上报道了这一发现 。
研究人员调查了2000户家庭成员中有MS病人的病史档案 。通过调查，他们发现了NR1H3产生结构变异的两户家庭 。这些家庭成员患有最严重的多发性硬化症 。
医学遗传专家Carles Vilarino-Guell是该报道的首席作者 。他注意到，约15%至20%的多发性硬化症病例都存在一种特殊的遗传成分，但这并未得到证实 。
Vilarino-Guell称，另外一项研究表明其他的基因与该病有关 。这些基因将患MS的风险提升了3% 。
研究人员对鼠类的基因NR1H3进行了试验 。移除该基因时，进行正常基因复制的老鼠出现了神经类问题 。包括髓磷脂产量的下降 。
髓磷脂对神经元外部蛋白质起保护作用 。它能够加速控制运动的电信号的传递 。MS的常见症状是肌无力以及丧失协调能力 。
很多试验团队正在研究如何修复MS患者的髓磷脂 。目前，治疗药物只能延缓病情 。无法彻底治愈该病 。
Vilarino-Guell说道，MS的诱因是单个基因缺陷也就意味着未来能够修复该基因缺陷 。也就是说多发性硬化症能够被治愈 。