Hi, all.
A new study of twins in California shows that environmental factors play a larger role than genetics in causing cases of autism, though both play important roles. This is a change for the autism researchers, who have been focusing more on genetics to the exclusion of environmental factors in recent years.
Note that "environmental factors" could include the multiple vaccinations that children receive after birth, though none of the news reports on this study or the paper itself mention this possibility. After the Wakefield affair, the media and the mainstream autism researchers have ruled that out in their minds, but I don't think it is a dead issue. The autism parents have a lot of personal experience that suggests otherwise.
Because I believe that autism and ME/CFS are the same disorder from a biochemical perspective (and probably from a genomic perspective as well), I think this study has relevance to ME/CFS causation as well. The numbers might be somewhat different for the contributions of genetics and environmental factors (including lifestyle-associated factors, stressors, etc.) in ME/CFS vs. autism because of the later onset of the former, but I think the results of this study are consistent with the proposition that both genetic and environmental factors are involved in the causation of cases of ME/CFS as well. This would also be consistent with other available research results in ME/CFS, including the recent study in Utah, and it is consistent with what I have proposed in the Glutathione Depletion--Methylation Cycle Block hypothesis, which applies to sporadic cases of ME/CFS. The situation must have been different for the epidemic or cluster cases, such as arose in the 80s in Incline Village, Lyndonville, and North Carolina. In those cases, the genetic contribution must be less. I think it is likely that a virulent virus (or retrovirus) was involved in these cases, which was able to impact people with less regard for their genomics than is true in the sporadic cases.
Best regards,
Rich
Here's the reference to the full paper:
http://archpsyc.ama-assn.org/cgi/content/full/archgenpsychiatry.2011.76
Here's an article from today's San Francisco Chronicle:
Study: Environmental Factors May Be Just as Important as Genes in Autism
By Alice Park Tuesday, July 5, 2011
"Autism is undeniably influenced by genes, but a new study suggests that environmental factors may also contribute significantly more than researchers previously thought to the developmental disorder. In fact, environmental factors may play at least as big a role as genes in causing autism.
"Dr. Joachim Hallmayer, a psychiatrist at the Stanford University School of Medicine, and his team report online in the Archives of General Psychiatry that shared environmental influences may account for as much as 55% of autism risk, while less than 40% can be attributed to genes.
"The study modeled risk, but did not specify which environmental factors were at play. But other research has implicated increasing maternal and paternal age, low birth weight, multiple pregnancies and any medications or infections to which an expectant mom is exposed during pregnancy.
"Autism, which affects at least 1% of children, is a complex disorder, so it's no surprise that both environmental and genetic factors contribute to its development. But in recent years, experts have focused intensively on the genetic components of autism; with the availability of more sophisticated tools to analyze genetic changes and development of disease, researchers have identified important clues about autism's roots in DNA.
"But the rise in autism spectrum disorders has occurred too quickly to be explained fully by genes. And scientists know that genetic changes don't occur in a vacuum. Such aberrations, combined with non-genetic factors, may offer a fuller picture of what causes the disorder.
"To determine how much either factor may contribute to autism, Hallmayer's group analyzed identical and fraternal twins, in which either one or both were diagnosed with autism or an autism spectrum disorder. Identical twins share identical genetic makeup, while fraternal twins are only as genetically similar as any two siblings. So by comparing the prevalence of autism between the two groups, the scientists were able to determine with relative assurance how much genes and shared environment contributed to the twins' conditions.
"The study found that the likelihood of both twins being affected by autism was higher among identical than fraternal twins. That suggests that genetics plays a key role in the disorder. But importantly, the chance of both twins being affected by autism was not low among fraternal twins, which is counter to what would be expected if genetics were the dominant factor.
"The study also found that autism rates among both identical and fraternal twins were higher than in the general population. That further suggests that environmental factors, probably shared by the twins as early as in the womb, contribute significantly to causing the disorder. "The fact that both groups have elevated rates suggests that something is making the two groups of twins similar to each other," says Neil Risch, director of the Institute for Human Genetics at University of California San Francisco and senior author on the paper. "Whether it occurs in utero, during childbirth or soon thereafter, we can't differentiate. But it suggests that something environmental is causing the twins to be alike."
"Risch notes that the results do not discount genetic factors by any means. "It's not either-or in terms of genetics or environment," he says. "We're not saying autism isn't genetic, because the huge majority of twins don't have autism. Obviously something is priming the risk, and it looks like that may be a genetic predisposition. So a genetic base and environmental factors together may explain autism better."
"The risk in twins with a genetic vulnerability may be triggered by being a multiple, for instance; something about the more crowded uterine environment may contribute to a greater chance of developing the disorder, Risch notes.
"The good news is that as researchers better understand the environmental factors that are responsible for autism, the more some of these factors may be modified to help lower the risk of the disorder. A fuller picture of the spectrum of both genetic and non-genetic contributors to autism may also help lead to more effective ways to treat it."
Read more: http://healthland.time.com/2011/07/...s-important-as-genes-in-autism/#ixzz1RFGzuunU
Rich
A new study of twins in California shows that environmental factors play a larger role than genetics in causing cases of autism, though both play important roles. This is a change for the autism researchers, who have been focusing more on genetics to the exclusion of environmental factors in recent years.
Note that "environmental factors" could include the multiple vaccinations that children receive after birth, though none of the news reports on this study or the paper itself mention this possibility. After the Wakefield affair, the media and the mainstream autism researchers have ruled that out in their minds, but I don't think it is a dead issue. The autism parents have a lot of personal experience that suggests otherwise.
Because I believe that autism and ME/CFS are the same disorder from a biochemical perspective (and probably from a genomic perspective as well), I think this study has relevance to ME/CFS causation as well. The numbers might be somewhat different for the contributions of genetics and environmental factors (including lifestyle-associated factors, stressors, etc.) in ME/CFS vs. autism because of the later onset of the former, but I think the results of this study are consistent with the proposition that both genetic and environmental factors are involved in the causation of cases of ME/CFS as well. This would also be consistent with other available research results in ME/CFS, including the recent study in Utah, and it is consistent with what I have proposed in the Glutathione Depletion--Methylation Cycle Block hypothesis, which applies to sporadic cases of ME/CFS. The situation must have been different for the epidemic or cluster cases, such as arose in the 80s in Incline Village, Lyndonville, and North Carolina. In those cases, the genetic contribution must be less. I think it is likely that a virulent virus (or retrovirus) was involved in these cases, which was able to impact people with less regard for their genomics than is true in the sporadic cases.
Best regards,
Rich
Here's the reference to the full paper:
http://archpsyc.ama-assn.org/cgi/content/full/archgenpsychiatry.2011.76
Here's an article from today's San Francisco Chronicle:
Study: Environmental Factors May Be Just as Important as Genes in Autism
By Alice Park Tuesday, July 5, 2011
"Autism is undeniably influenced by genes, but a new study suggests that environmental factors may also contribute significantly more than researchers previously thought to the developmental disorder. In fact, environmental factors may play at least as big a role as genes in causing autism.
"Dr. Joachim Hallmayer, a psychiatrist at the Stanford University School of Medicine, and his team report online in the Archives of General Psychiatry that shared environmental influences may account for as much as 55% of autism risk, while less than 40% can be attributed to genes.
"The study modeled risk, but did not specify which environmental factors were at play. But other research has implicated increasing maternal and paternal age, low birth weight, multiple pregnancies and any medications or infections to which an expectant mom is exposed during pregnancy.
"Autism, which affects at least 1% of children, is a complex disorder, so it's no surprise that both environmental and genetic factors contribute to its development. But in recent years, experts have focused intensively on the genetic components of autism; with the availability of more sophisticated tools to analyze genetic changes and development of disease, researchers have identified important clues about autism's roots in DNA.
"But the rise in autism spectrum disorders has occurred too quickly to be explained fully by genes. And scientists know that genetic changes don't occur in a vacuum. Such aberrations, combined with non-genetic factors, may offer a fuller picture of what causes the disorder.
"To determine how much either factor may contribute to autism, Hallmayer's group analyzed identical and fraternal twins, in which either one or both were diagnosed with autism or an autism spectrum disorder. Identical twins share identical genetic makeup, while fraternal twins are only as genetically similar as any two siblings. So by comparing the prevalence of autism between the two groups, the scientists were able to determine with relative assurance how much genes and shared environment contributed to the twins' conditions.
"The study found that the likelihood of both twins being affected by autism was higher among identical than fraternal twins. That suggests that genetics plays a key role in the disorder. But importantly, the chance of both twins being affected by autism was not low among fraternal twins, which is counter to what would be expected if genetics were the dominant factor.
"The study also found that autism rates among both identical and fraternal twins were higher than in the general population. That further suggests that environmental factors, probably shared by the twins as early as in the womb, contribute significantly to causing the disorder. "The fact that both groups have elevated rates suggests that something is making the two groups of twins similar to each other," says Neil Risch, director of the Institute for Human Genetics at University of California San Francisco and senior author on the paper. "Whether it occurs in utero, during childbirth or soon thereafter, we can't differentiate. But it suggests that something environmental is causing the twins to be alike."
"Risch notes that the results do not discount genetic factors by any means. "It's not either-or in terms of genetics or environment," he says. "We're not saying autism isn't genetic, because the huge majority of twins don't have autism. Obviously something is priming the risk, and it looks like that may be a genetic predisposition. So a genetic base and environmental factors together may explain autism better."
"The risk in twins with a genetic vulnerability may be triggered by being a multiple, for instance; something about the more crowded uterine environment may contribute to a greater chance of developing the disorder, Risch notes.
"The good news is that as researchers better understand the environmental factors that are responsible for autism, the more some of these factors may be modified to help lower the risk of the disorder. A fuller picture of the spectrum of both genetic and non-genetic contributors to autism may also help lead to more effective ways to treat it."
Read more: http://healthland.time.com/2011/07/...s-important-as-genes-in-autism/#ixzz1RFGzuunU
Rich
