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Amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig's disease and Charcot disease, is a specific disorder that involves the death of neurons. In a number of countries the term motor neurone disease (MND) is commonly used,〔(【引用サイトリンク】url=http://www.nhs.uk/conditions/Motor-neurone-disease/Pages/Introduction.aspx )〕 while others use that term for a group of five conditions of which ALS is the most common. ALS is characterized by stiff muscles, muscle twitching, and gradually worsening weakness due to muscle wasting.〔(【引用サイトリンク】title=Motor Neuron Diseases Fact Sheet )〕 This results in difficulty speaking, swallowing, and eventually breathing.〔 The cause is not known in 90% to 95% of cases. About 5–10% of cases are inherited from a person's parents. About half of these genetic cases are due to one of two specific genes. It results in the death of the neurons that control voluntary muscles. The diagnosis is based on a person's signs and symptoms with testing done to rule out other potential causes.〔 There is no known cure for ALS.〔 A medication called riluzole may extend life expectancy by about two to three months. Non-invasive ventilation may result in both improved quality and length of life. The disease usually starts around the age of 60 and in inherited cases around the age of 50.〔 The average survival from onset to death is three to four years. About 10% survive longer than 10 years.〔 Most die from respiratory failure. In much of the world, rates of ALS are unknown.〔 In Europe and the United States, the disease affects about 2 people per 100,000 per year.〔〔(【引用サイトリンク】url=http://aces.stanford.edu/acesmem2/EpiDescSporadic.html )〕 Descriptions of the disease date back to at least 1824 by Charles Bell.〔 In 1869, the connection between the symptoms and the underlying neurological problems were first described by Jean-Martin Charcot, who in 1874 began using the term amyotrophic lateral sclerosis. It became well known in the United States in the 20th century when it affected the baseball player Lou Gehrig,〔 and later when Stephen Hawking gained fame for his scientific achievements. In 2014 videos of the ice bucket challenge went viral on the internet and increased public awareness. == Signs and symptoms == The disorder causes muscle weakness and atrophy throughout the body due to the degeneration of the upper and lower motor neurons. Individuals affected by the disorder may ultimately lose the ability to initiate and control all voluntary movement, although bladder and bowel function and the muscles responsible for eye movement are usually spared until the final stages of the disorder. Cognitive function is generally spared for most people, although some (about 5%) also develop frontotemporal dementia. A higher proportion of people (30–50%) also have more subtle cognitive changes which may go unnoticed, but are revealed by detailed neuropsychological testing. Sometimes, ALS coexists in individuals who also experience dementia, degenerative muscle disorder, and degenerative bone disorder as part of a syndrome called multisystem proteinopathy. Sensory nerves and the autonomic nervous system are generally unaffected, meaning the majority of people with ALS maintain hearing, sight, touch, smell, and taste.〔http://www.ninds.nih.gov/disorders/amyotrophiclateralsclerosis/〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「amyotrophic lateral sclerosis」の詳細全文を読む スポンサード リンク
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