A minor nitpick, this study came out much earlier this year. I wrote about it in April although I believe it was published in March.

This is really a weak study and there are a number of problems with it:

The results were based on a parental report that was done at wide spaced intervals (4 weeks, 6 months, 18 months, 30 months, 42 month). I would have to question how much a parent would remember about incidents of diarrhoea, consistency of stools over a year period unless they were keeping detailed notes along the way (unlikely). And of course, tracking of other problems like abdominal pain is tricky at best when the children can’t talk (no data is included about the verbal status of the children).

The number of children with autism (76) is much, much smaller than the control population (12,805). For this to be relevant to autism I would think there would have to more children with autism included.

The data included in this study is from children born in 1991 and 1992, so it very dated. I think using a more recent group of children would have made the results much more useful and relevant.

There were other problems as well.

When you consider all of the problems this study does not tell us anything significant.

It as everything to do with your post. You cherrypick two studies you agree with as disproving all other studies with different results eg:

http://www.ncbi.nlm.nih.gov/pubmed/10547242?

@RAJ: Seriously, you don’t know what in the heck you’re talking about. How in the world does the non-controlled study above contradict anything in the post?

Besides, I’m sure Sullivan understands that the entire body of science on this issue is what matters, not one study here or there. If you look at the science as a whole, there’s no convincing evidence thus far that autism is associated with GI disease.

You can lead a horse to water…

http://gene.sfari.org/

ETA: Tom, Prometheus, and anyone else: you are welcome to continue the discussion should you like.

RAJ’s comment has no relationship to the blog post so I didn’t see the need to discuss it. Not that I caught the glaring mistake he made, and not that I’m not glad you pointed it out”.

It as everything to do with your post. You cherrypick two studies you agree with as disproving all other studies with different results eg:

http://www.ncbi.nlm.nih.gov/pubmed/10547242?

The Bailey et al 1995 twin study does the same thing. The study does a lot of conjecturing, dismissing the consistent evidence over many decades of an increase in unfavorable events in the pre peri and neonatal period as being unrelated to autism etiology because they are the consequence of earlier genetically influenced abnormal development, and that the presence of minor congenital anomolies in their sample proves their conjecture. Subsequent studies have shown that the presence of minor and major congenital anomolies in autism is low, between 10 and 14% and minor and major congenital anomolies are also present in 6 to 14% of healthy controls in the three studies I referenced.

Tom wrote:
“Either RAJ doesn’t understand genetics or he purposely misrepresents findings. From the damn abstract he claims invalidates autism micro deletions at 16p11.2:

“The assembled evidence indicates that recurrent 16p11.2 deletions are associated with variable clinical outcome, most likely arising from haploinsufficiency of one or more genes. The phenotypical spectrum ranges from MR and/or MCA, autism, learning and speech problems, to a normal phenotype.”

RAJ, your slip is showing”

Tom, that study showed no association between autism and 16P11.2 microdeletions, they were referring to earlier studies that made such a claim.

See Hakonarnon’s most recent publication based on AGRE data:

http://www.plosgenetics.org/ar.....en.1000536

Hakonarnon examining genetic data present in the AGRE multiple incident families reported a number of rare genetic variants contained in the AGRE dataset. The problem is that the same rare genetic variants he claimed were autism susecptbility genes have also been reported in studies that found the same genetic variants in mental retardation without autism.

Since the introduction of DSM-IV and ICD-10 in 1994 and all the ‘Gold Standard’ diagnostic tools based on the DSM-IV and ICD-10 diagnostic criteria the definition of autism is so ill-defined that researchers involved in autism see autism where researchers who specialize in specific mental retardation syndromes do not see autism. This is analogous to Justice Stewart Potter’s opinion in a Supreme Court case of pornography. Potter wrote “I can’t define pornography, but I know it when I see it”.

Nowhere is this most represented by the presence of Angelman Syndrome cases in the AGRE dataset. Hakonarnon claims the AGRE data set replicated the finding of genetic variants in the region of 15q11–13 and significantly, mutations in the single gene UBE3A.

These are the same genetic variants reported in Angelman’s Syndrome. Researchers specializing in Angelman’s Syndrome note that a diagnosis is based on mutations in these genetic regions. The features of Angelman’s Syndrome are severe mental retardation, seizures and ataxia. Angelman’s Syndrome has commonly been suggested as an Autism Genetic Syndrome by those specializing in autism research, yet those who specialize in Angelman’s Syndrome have noted that Angelman’s Synrome is often misdiagnosed as cerebral palsy or autism.

http://www.angelman.org/stay-informed/

Autism is so ill defined that healthy persons with acquired neurological damage have been found to have acquired autistic personality impairments based on Baron-Cohen’s autism-spectrum quotient test

To date, there is no genetic mutation that has been found to be specific to autism. The associations with ill-defined autism are based on interpretations always based on the bias of the beliefs of the interpretor.

Tom, or Sullivan, name one specific autism gene, just one.

thanks for taking the time (and space) to add your comment.

The same problem exists in twin and genetic studies. An hypothesis is proposed only to be refuted by subsequent reports.

This appears to be a “linker”, allowing RAJ to post an otherwise completely unrelated comment about genetics in a post about gut problems and autism.

Normally I would have let this non sequitur go unremarked. Unfortunately, RAJ’s understanding of genetics appears a bit thin in this comment and needs to be answered.

For example:

[1] While the Baley et al (1995) study may be the most cited twin study of autism, that doesn’t mean that it is the only or even the best study showing heritability of autism. Taniai et al (2008) showed a very high level of heritability in autism (more for females than males, oddly), as did Ronald et al (2006) and Hallmayer et al (2002). I could go on, but it would be merely beating the already dead horse. Suffice it to say that autism has been shown to be highly heritable.

[2] The Wier et al (2006), Stoicanescu (2007) [note: published in a Romanian journal] and Ohdo et al (2007) studies do not actually contradict Bailey et al (1995). In fact, their findings disagree somewhat with each other. I’m not sure what point RAJ was driving at, but it appears to have been something about physical anomalies, which are slightly more common in autistic children than is the norm (but – according to Ohdo et al, less common than in Trisomy 21).

[3] The Jacquemont et al (2006) citation used a 1 Mbp-resolution micro-array for their study. This means that they would have been able to detect only relatively large deletions and duplications. Since the “average” (there is a huge variation) gene size is about 10 to 15 Kbp, a 1 Mbp deletion/duplication could involve upwards of 100 genes. There is little wonder that the subjects they found were more dramatically affected.

[4] The “overhyped” Kumar et al (2008) article on 16p11.2 in a number of subjects with autism was not contradicted by the subsequent Bijlsma et al (2009) paper, which found that the 16p11.2 deletion was not invariably associated with autism, as the authors stated even in their abstract.

I’m not sure what RAJ is thinking with this set of citations. Is it an attempt to show that autism isn’t genetic? Who knows? Certainly not me.

What is clear is that RAJ is fixated on twin studies at the moment and doesn’t appear to like the ones that show autism to be highly heritable. While this is all very interesting, I don’t see what that has to do with the (lack of) connection between autism and gut problems, which was the topic of this post.

I apologize for using up space to rebut RAJ’s comment, but I couldn’t let it stand unanwered, even if it was not germane to the topic at hand.

Prometheus

Yeah, it was a non-sequitar. I really think that posting on LBRB is a privilege not a right. Repeated attempts to misrepresent deserve banishment. Maybe this would keep certain contributors on the straight and narrow.

RAJ’s comment has no relationship to the blog post so I didn’t see the need to discuss it. Not that I caught the glaring mistake he made, and not that I’m not glad you pointed it out.

“The assembled evidence indicates that recurrent 16p11.2 deletions are associated with variable clinical outcome, most likely arising from haploinsufficiency of one or more genes. The phenotypical spectrum ranges from MR and/or MCA, autism, learning and speech problems, to a normal phenotype.”

RAJ, your slip is showing.