Maciamo
05-12-10, 19:18
Autism is one of the most common and yet one of the least understood psychological disorders. Genetic inheritance, testosterone levels in the womb, environmental factors, brain damage, and even measles vaccinations have all been implicated, but none is sufficient alone to cause autism. Here is another clue from mitochondrial DNA that may explain some cases of autism.
Explaining autism - Energy drain : The cause of autism may be faulty mitochondria (http://www.economist.com/node/17626864?story_id=17626864&fsrc=rss)
One suggestion that does pop up from time to time is that the process which leads to autism involves faulty mitochondria. The mitochondria are a cell’s powerpacks. They disassemble sugar molecules and turn the energy thus liberated into a form that biochemical machinery can use. Mitochondrial faults could be caused by broken genes, by environmental effects, or by a combination of the two.
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Dr Giulivi found that mitochondria from children with autism consumed far less oxygen than those from the control group. That is a sign of lower activity. One important set of enzymes—NADH oxidases—used, on average, only a third as much oxygen in autistic children as they did in non-autists, and eight of the autistic children had significantly lower NADH-oxidase activity than is normal.
The mitochondria of the autistic children also leaked damaging oxygen-rich chemicals such as hydrogen peroxide. These are a normal by-product of mitochondrial activity, but are usually mopped up by special enzymes before they can escape and cause harm—for instance, by damaging a cell’s DNA. The level of hydrogen peroxide in the cells of autistic children was twice that found in non-autists. Such high levels suggest the brains of autistic children are exposed to a lot of oxidative stress, something that would probably cause cumulative damage.
And here is the original article from the Journal of the American Medical Association Mitochondrial Dysfunction in Autism (http://jama.ama-assn.org/content/304/21/2389.abstract)
The mutations involved are unfortunately not mentioned in the abstract.
Explaining autism - Energy drain : The cause of autism may be faulty mitochondria (http://www.economist.com/node/17626864?story_id=17626864&fsrc=rss)
One suggestion that does pop up from time to time is that the process which leads to autism involves faulty mitochondria. The mitochondria are a cell’s powerpacks. They disassemble sugar molecules and turn the energy thus liberated into a form that biochemical machinery can use. Mitochondrial faults could be caused by broken genes, by environmental effects, or by a combination of the two.
...
Dr Giulivi found that mitochondria from children with autism consumed far less oxygen than those from the control group. That is a sign of lower activity. One important set of enzymes—NADH oxidases—used, on average, only a third as much oxygen in autistic children as they did in non-autists, and eight of the autistic children had significantly lower NADH-oxidase activity than is normal.
The mitochondria of the autistic children also leaked damaging oxygen-rich chemicals such as hydrogen peroxide. These are a normal by-product of mitochondrial activity, but are usually mopped up by special enzymes before they can escape and cause harm—for instance, by damaging a cell’s DNA. The level of hydrogen peroxide in the cells of autistic children was twice that found in non-autists. Such high levels suggest the brains of autistic children are exposed to a lot of oxidative stress, something that would probably cause cumulative damage.
And here is the original article from the Journal of the American Medical Association Mitochondrial Dysfunction in Autism (http://jama.ama-assn.org/content/304/21/2389.abstract)
The mutations involved are unfortunately not mentioned in the abstract.