Mutations in the CHD8 gene and ASD
There is increasing evidence of mutations in the CHD8 gene, which is found on chromosome 14, causing a large number of cases of ASD. Some mutations seem quite specific to ASD, with about 90% prevalence of ASD when using gold standard measures. It can cause other abnormalities: Macrocephaly (head circumference greater than the 98th percentile) in early childhood, caused by a larger-than-normal head at birth followed by a rapid growth in head size shortly after birth; distinctive facial features, such as a prominent brow ridge, wide-set eyes, and a short nose with a wide tip (pictures at link); intellectual disability, though patients with average IQ have been found (but none with above-average IQ); and gastrointestinal disturbances, including recurrent constipation and an increased risk for cancers of that system. This article, published in December, reviews the evidence:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4681771/
I find this very interesting, because I seem to fit this profile. I'm on the spectrum, I had macrocephaly at least in Kindergarten, my facial features seem to match those of the kids (more on that below), and I have lots of GI problems, including the constipation. If you look at Figure 1, you can see some examples of those facial features. As a kid, I seemed to most resemble the kids on the upper left and the upper right. As an adult, the features of my brows, forehead, eyes, and nose seem to most resemble the kid on the bottom middle (who seems to be a teenager). My eyebrows are very closely set over my eyes, I have a fivehead, and I have that same nose shape with the wide tip at the bottom and the nostrils visible from the front. If you look closely, you can see very subtle curved lines under that kid's eyes that start up near the nose and curve down away from it on either side. I have those very same curved lines. I also have a pointy chin, though not quite like my sister's, who is said to have a "Jay Leno chin."
I have recurrent constipation, though right now my stools are loose. When I've had constipation, and for a while after stopping, I would for weeks have blood on the toilet paper when I wipe after doing a bowel movement. I also have bad, almost constant heartburn. I remember a bad bout of constipation in or around 3rd grade, but I don't remember much about my bowel movements then.
The only thing I don't have is intellectual disability, but an average IQ doesn't disprove a connection. What was not found were above-average IQs. The highest IQ I've tested for is 113, which is called "high average." I guess that would qualify as average.
I wonder if I should try getting tested. If what they say about the cancer risk is right, then doing so might save my life.
Does anyone else seem to share these signs and symptoms of what seems to be a CHD8 disorder?
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"You have a responsibility to consider all sides of a problem and a responsibility to make a judgment and a responsibility to care for all involved." --Ian Danskin
I think you may have a hard sell with the genetic testing - getting it paid for by your insurance, I mean. And it may be impossible if there isn't a standardized test for this gene.
Anyone with longstanding gastrointestinal disorders probably has an increased chance of cancers in those systems. I think you are best served with a proactive treatment stance, such as maintenance medication for GERD or constipation. And you would do these things whether or not you had this CHD8 gene.
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A finger in every pie.
Better look to something like 23&me for testing.
But I would be very cautious about over-interpreting this, which is not really a new finding:
http://www.sciencedaily.com/releases/20 ... 125851.htm
15 cases of CHD8 mutation out of 6,176 autistic people is not evidence that this gene is a major contributor to autism.
It is fascinating work and opens interesting avenues of study, but doesn't suggest any kind of reliable autism genetic test is coming anytime soon.
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Don't believe the gender note under my avatar. A WP bug means I can't fix it.
I have a fairly large head, and slight gastrointestinal problems, and I also have a "high average" IQ consistently: Superior in Verbal, Average in Performance.
I don't have prominent eye brow ridges, or the nose described, though.
Based upon my recollection of old case studies, gastrointestinal problems seemed to be prevalent in "regressive" autism--the type where language and social skills were acquired, but were lost by age 2 1/2.
Unfortunately 23andme doesn't test this gene. But maybe another gene testing company would. I think you should check that they test this particular gene before shilling out the money for testing.
You get access to your raw data and can look for whatever you want in it with online tools.
http://lifehacker.com/5802559/how-to-de ... ce-23andme
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Don't believe the gender note under my avatar. A WP bug means I can't fix it.
Unfortunately 23andme doesn't test this gene. But maybe another gene testing company would. I think you should check that they test this particular gene before shilling out the money for testing.
You get access to your raw data and can look for whatever you want in it with online tools.
http://lifehacker.com/5802559/how-to-de ... ce-23andme
I was looking in the raw data and it didn't have the CHD8 gene. Not every gene gets genotyped by their test.
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