Gene Mutations and Autism Risk: A Link?

In any discussion about how common autism has become — 1 in 88 children in the U.S. are now diagnosed with the neurodevelopmental disorder — the question of “why” inevitably rises. Many autism experts emphasize how the expanded DSM  criteria for autism spectrum disorders have greatly contributed to the rise in diagnoses. Scientists keep looking for possible environmental and genetic factors. Three new studies have just been published in the journal Nature about several gene mutations that, the researchers says, are linked to a higher risk of autism.

The genes in question are de novo mutations — spontaneous copy number mutations in the DNA. Previous studies have shown that such gene mutations occur more often in cases of sporadic autism rather than they do in familial (heritable) cases or than in children who do not have an autism spectrum disorder.

In the three new Nature studies, scientists examined genetic material from blood samples from families in which the parents had “no signs of autism” and an autistic child.

(1) A study under Dr. Matthew W. State, a professor of genetics and child psychiatry at Yale University, looked for de novo mutations in samples from 200 people with an ASD diagnosis and in their parents and siblings who did not have such a diagnosis. Two unrelated autistic  children were found to have de novo mutations in the same gene.

(2) A study of 209 families under Dr. Evan E. Eichler, a professor of genome sciences at the University of Washington in Seattle, found a de novo gene mutation in a different gene suspected of a possible link to autism risk. One autistic child in Dr. State’s study was found to have a de novo mutation in the very same gene.

(3) A third study under Mark J. Daly of Harvard University analysed the de novo gene mutations from the other studies as well as a third gene and found that, as noted in The New York Times, “kids with autism have a slightly higher rate, on average, and the effects are more severe.”

One caveat regarding de novo mutations and “sporadic autism”: The autistic children in the three new studies are described as having no family members with an autism diagnosis. However, it is not unusual for parents of autistic children to see some aspects of their child — a tendency to be obsessive-compulsive, difficulties with attention, perhaps — in themselves; some parents have even been diagnosed with Asperger’s after their child received an ASD diagnosis. If the expanded criteria for autism were applied to parents and siblings, might they not be found to have some “autistic traits”?

Parental Age and Autism Risk

All three studies also noted that, the older parents are, the greater the risk for giving birth to a child at risk for an autism diagnosis. Earlier studies have also suggested that older parents (both male and female) are more at risk for having an autistic child.

There are some caveats about correlating parental age and autism risk. For instance, parents who are “different” in some way, having ADHD or Asperger’s Syndrome, perhaps, may be more likely to have children later, due to their own challenges with relationships and social interactions.

So What Do These Studies Tell Us?

Currently autism is diagnosed by the observation of clinicians and psychologists, who examine a child to see if she or he has sufficient quantities of symptoms to qualify for an ASD diagnosis. In other words, diagnosing autism retains an element of subjectivity. The still-changing and evolving criteria for autism add to the challenge and, too, the confusion. Researchers have been hopeful that genetic studies might point to a possible biomarker for autism.

Jonathan Sebat, a professor of psychiatry and cellular and molecular medicine at the University of California, San Diego who was not involved in the three new studies, describes the studies not as a “breakthrough, because we knew this was coming” but as a “turning point.” Sebat said that “in the next year or two” we can likely expect to find “20, 30, maybe more such mutations.”

Like previous genetic studies about autism, the new studies have found rare genetic mutations in only a very few individuals vs. some “autism gene” in many individuals. Developing therapies from the new studies’ findings is a long way off. What the new studies, and future studies like them, may end up telling us is that “what is known generally as autism may represent a broad category of related but biologically distinct conditions.” Finding a biomarker that would definitely say “this child is autistic” remains elusive.

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Photo by dullhunk

45 comments

Jeanne R
Jeanne Rabout a month ago

Thank you for sharing.

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Jeanne R
Jeanne Rabout a month ago

Thank you for sharing.

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Jeanne R
Jeanne Rabout a month ago

Thank you for sharing.

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Jeanne R
Jeanne Rabout a month ago

Thank you for sharing.

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Jeanne R
Jeanne Rabout a month ago

Thank you for sharing.

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Kenneth L.
Kenneth L5 years ago

Since the terms 'autism', 'autism spectrum disorder' and 'asperger's syndrome' were all created by one field, Psychiatry, here is what the Chairman of the Task Force of the current DSM 4 (the book of 374 'mental disorders' including the above 3) says about the 'epidemic of autism':

"DSM 4 gave autism purchase by introducing a milder form that is close to the extremely populous boundary of normality. Then autism took flight on the wings of definitional diffusion, internet contagion, financial incentive, and naïve interpretation of epidemiological results.
The autism “epidemic” is set to spread further starting in May 2013, when the next revision of the diagnostic manual (DSM 5) will be published. The DSM 5 definition of an “autistic spectrum” will cast an even wider net, capturing many people now considered to be normal or to have another disorder" Dr. Allen Frances, professor emeritus of Psychiatry

Here is what another professor emeritus of Psychiatry says:
"We don't have an epidemic of mental illness, we have an epidemic of psychiatry." Dr. Thomas Szasz

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Mit Wes
Mit Wes5 years ago

"It couldn't POSSIBLY be the
WATER filled with amoeba, parasites, DRUGS, bird and animal FECES, DEAD ANIMALS
,PESTICIDES, antibiotics and every manner of unidentifiable crap! " - Jane B.

Well, we can immediately rule out amoeba[s], parasites, bird and animal FECES, DEAD ANIMALS, as that pretty much describes the water supplies of European cities up until modern water purification systems were put in place.

And, Barbara G., you have to realize all our food, no matter what the source, contains genes, including whatever bacteria may have been on and in the food at the time of eating. According to you, we acquire behaviors of other species simply by eating their genes. So, if you eat salmon, you'll feel like swimming, eat chicken, you'll be doing the chicken dance soon ! If you eat eggplant, well, let's just say that'll make you as happy as one, according to your theory.

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Barbara T.
Barbara Talbert5 years ago

Jane B. you are right but you forgot to mention the foods we are eating that are genetically engineered with genes from the lower orders of life and the adjuvants and mediums that vaccines are grown in. One mother mentioned that her son likes to hang over the couch, another that her child constantly flaps his hands. These behaviors belong to and are the intrinsic imprinting of certain orders of life. My heart aches for these children and their parents who are part of the great unfettered genetic experiment with food.

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Ute L.
Ute Lehmann5 years ago

I think autism and exspecally asperger is a gift: we are high intelligent humans, and I want to stay how I am. I will not get normal, I hate to get normal. I dont understand why asperger and autism-humans are not allowes to get children.i dont understand, why the aspergers´and autistic´children have to raise up like "normal" children...Without aspies and autis there would be no electric light, no higher mathematic, no moon landing, no computers,no higher physics--this is has been all done by us: the aspies and high autistic humans. I want equal rights and no racism which prefers non-autistic/non-aspergers´ normal people to us, who are said to be "ill". We are not ill. We dont talk with people which thing themselves to be sane and tell us to be insane. We are not insane, we have a high IQ. But often we are not allowed to use it. Most people want us to talk about the weather at overcrowded sandwichbars and loud music--a "social event" to make "small talk" by staring each other in the eyes? Why no "big talk" on "big, social meatings"?----But photographing and collecting clouds in this way is insane, but always silly talk about the weather (often without to know how weather works)is sane? Higher intelligence is not a disease! I love it to be autistic!The increase has to do with the change of the autistic people themselves: We use computers, We know about our rights. We know we are humans with the human rights .We are many. We are intelligent, some extremly in ma

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Ute L.
Ute Lehmann5 years ago

The increase has to do with the change of the autistic people themselves: We use computers, We know about our rights. We know we are humans with the human rights .We are many. We are intelligent, some extremly in mathematics and poorly in language. We marry. We get children and are proud of them. We dont need the acceptance of non-autistic people any more. We accept ourselves how we are. We are strong,, we get our children, we get our children back some day. We are friendly, we love peace, but we are more intelligent in a special way. And we fight for our freedom in all situations of life...

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