“Autism is genetic”?
I don’t think so. Consider the hopeless Wired Magazine
journalist, Amy Wallace, making the following statement:
“In fact, the growing body of science indicates
that the autistic spectrum — which may well turn out to encompass
several discrete conditions — may largely be genetic in origin. In
April, the journal Nature published two studies that analyzed the
genes of almost 10,000 people and identified a common genetic
variant present in approximately 65 percent of autistic children.”
Ms. Wallace, like many other reporters, offers two separate misstatements here that must be addressed:
First, she suggests that the “the growing body of science indicates that the autistic spectrum may largely be genetic in origin.” This comment is absurd, particularly given what a crisis the world of genetic researchers are actually going through, as described in an excellent article published in the New York Times in April of this year called, “Genes Show Limited Value in Predicting Diseases”:
“The genetic analysis of common disease is turning out to be a lot more complex than expected. Since the human genome was decoded in 2003, researchers have been developing a powerful method for comparing the genomes of patients and healthy people, with the hope of pinpointing the DNA changes responsible for common diseases. This method, called a genomewide association study, has proved technically successful despite many skeptics’ initial doubts. But it has been disappointing in that the kind of genetic variation it detects has turned out to explain surprisingly little of the genetic links to most diseases…Unlike the rare diseases caused by a change affecting only one gene, common diseases like cancer and diabetes are caused by a set of several genetic variations in each person. Since these common diseases generally strike later in life, after people have had children, the theory has been that natural selection is powerless to weed them out. The problem addressed in the commentaries is that these diseases were expected to be promoted by genetic variations that are common in the population. More than 100 genomewide association studies, often involving thousands of patients in several countries, have now been completed for many diseases, and some common variants have been found. But in almost all cases they carry only a modest risk for the disease. Most of the genetic link to disease remains unexplained.”
Autism is perhaps the most prevalent of many diseases where the search for common variants has been a bust. Like clockwork, a new finding of a variant in autism is announced in one study, only to be unreproducible in the next (due to random chance common in genome-wide analysis) and explained perfectly by Mark Blaxill (HERE).
If autism were genetic, children would need to have specific genes in order to have the disorder, and none, and I mean NONE, have been found.
As one example, a genome-wide study on autism (more on the study in a moment) appeared in the journal Nature in October 2009. The researchers, from Harvard and MIT, were surprisingly forthright in characterizing the current state of genetic autism research:
“Modern approaches that harness genome-scale technologies have begun to yield some insights into autism and its genetic underpinnings. However, the relative importance of common genetic variants, which are generally present in the human population at a frequency of about 5%, as well as other forms of genetic variation, remains an unresolved question…Although the Nature paper identifies a handful of new genes and genomic regions, the researchers emphasize that the findings are just one piece of a very large — and mostly unfinished — puzzle.”
Unresolved? Mostly unfinished puzzle? Unlike many journalists, these researchers don’t sound very definitive. In fact, in the study itself, the researchers spell it out even more clearly, saying “attempts to identify specific susceptibility genes [to autism] have thus far met with limited success.”
Looking at the website of Autism Speaks, an organization that has had frequent run-ins with our community but certainly stands alone as the largest organization dedicated to autism science states:
“The best scientific evidence available to us today points toward a potential for various combinations of factors causing autism – multiple genetic components that may cause autism on their own or possibly when combined with exposure to as yet undetermined environmental factors.”
“Genes alone do not tell the whole story. Recent increases in chronic diseases like diabetes, childhood asthma, obesity or autism cannot be due to major shifts in the human gene pool as those changes take much more time to occur. They must be due to changes in the environment, including diet and physical activity, which may produce disease in genetically predisposed persons."
Did Dr. Collins say “autism”? Yes, he did. On one side of the “genes cause autism” debate, you have the Director of the NIH and every real scientist in the autism field. On the other side, you have vaccine apologists, uninformed journalists, and genetic researchers trumping up meaningless conclusions to facilitate more study dollars from unwitting organizations like Autism Speaks and the Simons Foundation.
Back to the Nature study, and Amy Wallace again, where she writes:
“In April, the journal Nature published two studies that analyzed the genes of almost 10,000 people and identified a common genetic variant present in approximately 65 percent of autistic children.”
She is correct, two studies were published in Nature in April 2009 related to autism and genetics. What Ms. Wallace fails to mention is that both studies came from the same place: The Children’s Hospital of Philadelphia, which happens to be Paul Offit’s employer.
Ms. Wallace is right, one of the studies did find a common genetic variant present in 65% of autistic children. But, what Ms. Wallace fails to mention, a fact that might leave the reader with a very different impression, is that 61% of the controls in the study – the children without autism – had the same variant. 65% vs. 61%? As is typically the case in genome-wide findings, it was likely the product of chance, nothing more. How come we never get this context when new studies are released?
(For those of you wanting more, read the study (HERE). If you go to table 2 on page 3, find the column labeled “Case MAF” and subtract the listed number from 1.0: So, 1.0-0.35=65%. Doing the same math with “Control MAF” gets you the 61% number.)
It actually gets better. Autism studies on genetic variants are plagued by this failure of replication issue. One set of researchers runs data on hundreds of thousands of genes. Invariably, they find correlations. A new set of researchers use different subjects and try to replicate the findings and finds nothing, and then the cycle repeats itself. In the case of the genetic variant that Ms. Wallace noted, the one that 65% of the kids with autism had (5p14.1, SNP rs4307059), it didn’t take long for the failure of replication to take place.
Remember the journal article in Nature I quoted above? It came out in October 2009. It’s called, “A genome-wide linkage and association scan reveals novel loci for autism” and the article mentions:
“Although there was significant overlap between study samples, each of these scans contained a large set of unique families, so we sought to evaluate independent evidence of the top SNP (rs4307059) reported at 5p14 [this is the gene from the CHP study Ms. Wallace cites at 65%]. This SNP happens to be directly genotyped by both Affymetrix and Illumina platforms. We have a sizable number (n 5 796) of affected subjects with two parents genotyped (and of predominantly similar European background). However, we observed no support for association at this locus (T:U 354:335 in favour of the minor allele, a trend in the opposite direction as reported).”
English translation: not only could they not find an association on the gene where an uneducated journalist reported 65% of children with autism carried it, they actually found that when they ran the numbers, the kids WITHOUT autism were MORE likely to carry it. Said differently, the chances that this variant means anything related to autism is nearly zero.
The devil is in the details, AoA readers, and I hope we can all do our part to refute the completely unfounded statements that genetic researchers have done anything to figure out the origins of autism. I will end with a great quote from our very own Mark Blaxill:
“Autism rates are now up to more than 1% of American children, nearly 2% of boys. Genetic research is in disarray, reeling from years of incoherent findings and an incoherent logic that ihas become increasingly exposed. We all get tired of saying it, but it bears repeating that there’s no such thing as a genetic epidemic. Yet NIH continues to pour millions more of our tax dollars down the gene hunting rat hole and, in a trend that is even more disturbing, the new administration appears to be doubling down on the failures of the past.
In the face of such obvious irrationality from so many highly educated analysts, it’s enough to make you ask, do any of these people have a brain?”
Author’s note: If parts of my writing here seem familiar, it’s because I have borrowed and paraphrased myself from past AoA articles I have written.