Genetics of Autism

Autism is a mysterious neurological disorder that has seen an upsurge of diagnoses to the point where most children have some form of it. It can be relatively unnoticeable or it can be distracting. It is considered a neurological disorder, but genetics has been linked to it. I was watching ABC News Thursday evening when something very interesting came up about Autism. Harvard researchers have found genes that are believed to be associated with Autism. The genes believed to be associated are genes that are “turned off” meaning they could potentially be turned back on. This gives hope to those who have a severe case or have children with a severe case for future effective treatment.

In looking for that treatment, one of ABC’s links gave some very helpful and important information about what to look for when looking for known developed and well tested treatments. Finding that quick answer may be desirable but may be the wrong answer in the long run.

• Science – Science uses specific, time-honored tools to put hunches or hypotheses to logical and empirical tests. Some of those tools include operational definitions of the phenomena of interest; direct, accurate, reliable, and objective measurement; controlled experiments; reliance on objective data for drawing conclusions and making predictions; and independent verification of effects.

  Science does not take assertions or observations at face value, but seeks proof. Good scientists differentiate opinions, beliefs, and speculations from demonstrated facts; they don’t make claims without supporting objective data. (ASAT) Good sciences, Physics, Psychology, Neurology, Pathology, Biology, Meteorology, Physiology, and many other “ologies.”

• Pseudoscience – this tries to lend credibility to beliefs, speculations, and untested assumptions by making them appear scientific — for example, by using scientific jargon, endorsements from individuals with “scientific” credentials, perhaps even some numbers or graphs. (ASAT) If you’ve seen those late night ads for some sort of pill or something that needs to be put into the body, where Dr. So-and-so is endorsing it. This is an example. That person may be a real doctor, but might be a PhD. of something else like Philosophy, which has nothing to do with health. Known Pseudosciences are the Paranormal, New age stuff, Creationism, Astrology, etc.

• Antiscience – this is the outright rejection of the time-tested methods of science as a means of producing valid and useful knowledge. The extreme antiscientific view is that there are no objective facts; all knowledge is made up of personal interpretations of phenomena. (ASAT) This is new to me. I’ve heard of Pseudoscience but not Antiscience. I don’t know who would believe this type of science. I can’t even give an example of an antiscience. This type of science sounds like some sort of existential issue. How would they explain their own existence? Alright, I’m gonna stop myself right here before this becomes any longer!

National Institute of Neurological Disorders and Stroke for more information about Autism.

I found an interesting article about this very subject from ScienceDaily. I don’t know how often people click links on a blog, so I posted the article.

Common Mechanisms May Underlie Autism’s Seemingly Diverse Mutations

ScienceDaily ( July 11, 2008 ) — Many of the seemingly disparate mutations recently discovered in autism may share common underlying mechanisms, say researchers supported in part by the National Institute of Mental Health (NIMH)*, a part of the National Institutes of Health (NIH). The mutations may disrupt specific genes that are vital to the developing brain, and which are turned on and off by experience-triggered neuronal activity.

A research team led by Christopher Walsh, M.D., Ph.D., and Eric Morrow, M.D., Ph.D., of Harvard University, found two large sections missing on chromosomes in people with autism and traced them to likely inherited mutations in such genes regulated by neuronal activity.

The study breaks new ground for complex disorders like autism, taking advantage of a shortcut to genetic discovery by sampling families in which parents are cousins. The researchers found genes and mutations associated with autism in 88 families from the Middle East, Turkey and Pakistan in which cousins married and had children with the disorder.

“The emerging picture of the genetics of autism is quite surprising. There appear to be many separate mutations involved, with each family having a different genetic cause,” explained NIMH Director Thomas R. Insel, M.D. “The one unifying observation from this new report is that all of the relevant mutations could disrupt the formation of vital neural connections during a critical period when experience is shaping the developing brain.”

Earlier studies had suggested that the individually rare mutations are present in at least 10 percent of sporadic cases of autism, which is the most common form.

The researchers used a technique that pinpoints from a relatively small group of families genes responsible for disorders that can be amplified by parenthood among relatives, which can increase transmission of recessive diseases. Evidence had hinted at such transmission in autism, and the large amount of genetic information obtainable from such families reduced the need for a much larger sample including many families with multiple affected members.

The ratio of females to males with autism — normally one female to four males — was less lopsided in such families in which parents share a common recent ancestor. This ratio equalized even more in a subset of these families with more than one affected member, suggesting a doubling of the rate of autism, due to recessive causes on non-sex-linked chromosomes. Also, autism-linked spontaneous deletions and duplications of genetic material were relatively uncommon in these families, suggesting recessive inherited causes.

The researchers found multiple different genetic causes of autism in different individuals with little overlap between the families in which parents shared ancestry. Yet a few large inherited autism-linked deletions, likely mutations, in a minority of families stood out. The largest turned out to be in or near genes regulated, directly or indirectly, by neuronal activity.

“Autism symptoms emerge at an age when the developing brain is refining the connections between neurons in response to a child’s experience,” explained Walsh. “Whether or not certain important genes turn on is thus dependent on experience-triggered neural activity. Disruption of this refinement process may be a common mechanism of autism-associated mutations.”

Can normal function be revived?

Interestingly, only one chromosome deletion found in the Middle Eastern families actually removed a gene — in most cases, what was lost was a region adjacent to the gene that contains its “on/off” switches. This has important implications for therapy, because it suggests that autism mutations don’t always remove a gene altogether, but only inhibit its activity in certain contexts, says Eric Morrow, MD, PhD, of Massachusetts General Hospital, who is co-first author of the paper with Seung-Yun Yoo, PhD. “This means that we would not need to replace the gene, if we could only figure out how to reactivate it, perhaps with medications,” says Morrow, who also holds appointments at BIDMC and Children’s.

The findings also support the use of behavioral therapies in autism, which expose children to a rich environment and highly repetitive activities that may help turn on the genes and strengthen synaptic connections, Morrow adds.

The study was also supported in part by the NIH’s National Center for Research Resources, National Human Genome Research Institute, Eunice Kennedy Shriver National Institute of Child and Human Development, and the National Institute on Neurological Disorders and Stroke.

ScienceDaily article found on 10 July.