Seafood Consumption and Blood Mercury Concentrations in Jamaican Children With and Without Autism Spectrum Disorders.

12 Apr

In yet another study on mercury and autism, a team from the University of Texas has investigated blood mercury levels in children with autism spectrum disorders (ASDs). In Seafood Consumption and Blood Mercury Concentrations in Jamaican Children With and Without Autism Spectrum Disorders they report that “After controlling for the child’s frequency of seafood consumption, maternal age, and parental education, we did not find a significant difference (P = 0.61) between blood mercury concentrations and ASDs. ”

“we did not find a significant difference between blood mercury concentrations and ASDs”

Here is the abstract:

Mercury is a toxic metal shown to have harmful effects on human health. Several studies have reported high blood mercury concentrations as a risk factor for autism spectrum disorders (ASDs), while other studies have reported no such association. The goal of this study was to investigate the association between blood mercury concentrations in children and ASDs. Moreover, we investigated the role of seafood consumption in relation to blood mercury concentrations in Jamaican children. Based on data for 65 sex- and age-matched pairs (2-8 years), we used a General Linear Model to test whether there is an association between blood mercury concentrations and ASDs. After controlling for the child’s frequency of seafood consumption, maternal age, and parental education, we did not find a significant difference (P = 0.61) between blood mercury concentrations and ASDs. However, in both cases and control groups, children who ate certain types of seafood (i.e., salt water fish, sardine, or mackerel fish) had significantly higher (all P < 0.05) geometric means blood mercury concentration which were about 3.5 times that of children living in the US or Canada. Our findings also indicate that Jamaican children with parents who both had education up to high school are at a higher risk of exposure to mercury compared to children with at least one parent who had education beyond high school. Based on our findings, we recommend additional education to Jamaican parents regarding potential hazards of elevated blood mercury concentrations, and its association with seafood consumption and type of seafood.

Members of this team have other work on autism in Jamaica. Last year they presented Paternal and Maternal Age Are Jointly Related to Autism Spectrum Disorders In Jamaican Children at IMFAR. which had goals of:

This study’s primary objectives were to investigate whether environmental exposures to mercury, lead, arsenic and cadmium play a role in autism. Additionally, we investigated other potential risk factors for autism, including maternal and paternal age

So we see that the recently released paper is part of the conclusion of that study, which was incomplete at the time of abstract submission for IMFAR. I believe this team is reporting again at IMFAR 2012.

Why bring this up? It’s a relatively small study on a topic that has been well covered in the past: autism risk and mercury exposure. Besides, do even supporters of the autism/mercury hypothesis think that blood levels of mercury are a good indicator to track? The answer is “yes” when blood levels might implicate mercury and “no” when blood levels do not (as is this case).

The mercury/autism hypothesis has a long history, but it is worth noting that there was a great deal of excitement a few years ago when a researcher claimed that by re-analyzing an existing dataset she could show a correlation between blood mercury levels and autism. Porf. DeSoto’s 2007 paper was Blood Levels of Mercury Are Related to Diagnosis of Autism: A Reanalysis of an Important Data Set. The re-analysis was criticized (e.g. Autism Street’s A Tale Of Two Tails and A Photon in the Darkness’ Winter Potpourri). As noted, the re-analysis was also welcomed in some circles, including an article by Age of Autism’s Mark Blaxill: When Smart Scientists Make Stupid Mistakes:

This is an important and unexpected finding. It supports one of the central hypotheses at the heart of the autism-mercury controversy and suggests that the excretion deficit in autistic children might persist longer than anyone had guessed.

The idea that correlations between blood levels in autistics could be “an important…finding” was downplayed a great deal a few years later after Prof. Hertz-Picciotto’s team at the U.C. Davis MIND Institute came out with a study, Blood mercury concentrations in CHARGE Study children with and without autism. The MIND team concluded, “After accounting for dietary and other differences in Hg exposures, total Hg in blood was neither elevated nor reduced in CHARGE Study preschoolers with AU/ASD compared with unaffected controls, and resembled those of nationally representative samples”. Key in that conclusion–“after accounting for dietary and other differences in Hg exposures”. This is something that was not done in the dataset that Prof. DeSoto re-analyzed.

Which led to a press release from Mr. Blaxill’s organization, SafeMinds: New California Study on Children’s Blood Mercury Levels Leaves Unanswered Questions About Mercury’s Role in Autism which downplayed any impact of the MIND study while somewhat ironically using DeSoto’s re-analysis for support. In other words, new research on blood-levels of mercury are not so important because we have older, uncontrolled, data which does say blood-levels are important.

More telling of the shift in support for blood mercury concentrations is this 2010 comment from Katie Wright at the Age of Autism:

Measuring random blood levels is a fruitless exercise, like testing ASD kids for grass allergies in the wintertime.

Don’t assume the door was closed on blood levels of mercury. In 2011 a paper was published, Theoretical aspects of autism: Causes—A review, which stated that there was evidence for a “metal metabolism disorder” in autistics and Supporting this relationship are reports documenting that heavy metals are increased in the blood and urine of autistic subjects”. This review was not surprisingly welcomed by groups promoting the idea that vaccines and/or mercury cause autism as well as criticized by many (for example)

So while, yes, these groups do welcome research indicating that blood levels of mercury are important in discussing autism research, they are also quite prepared to downplay using on blood-levels of mercury in studies which don’t support the mercury-causation idea.

Which is why one will not be surprised that research such as this new paper from Jamaica will have little impact on the mercury-causes-autism movement. Well, that and the fact that it is evidence against causation.

For those who claim that mercury testing should be done earlier–that testing autistic children is too late (“like testing ASD kids for grass allergies in the wintertime”) there is another study in process, one that was presented at IMFAR 2011. Prenatal and Neonatal Peripheral Blood Mercury Levels and Autism Spectrum Disorders which I don’t believe has been published yet. The conclusion from that study: “Levels of total mercury in serum collected from mothers during mid-pregnancy and in blood collected from infants at birth were not associated with risk of ASD.”

Mercury levels in pregnant women aren’t correlated to whether their children have autism. Mercury levels in newborns aren’t associated with autism risk. Blood levels in autistics are not correlated with their diagnosis. Add to this the fact that autism risk is not correlated to levels of mercury exposure from vaccines or immunoglobulins (e.g. Prenatal and Infant Exposure to Thimerosal From Vaccines and Immunoglobulins and Risk of Autism). And the fact that autism does not look like mercury intoxication. And that autism prevalence estimates continue to rise even after mercury was removed from vaccines. Why is there still support for this idea?

Autism Science Foundation fundraiser on Philanthroper

12 Apr

The Autism Science Foundation (ASF) is running a fundraiser on Philanthroper. These are short (1 day) fundraisers with small amounts ($1 to $10). Below is the text from the fundraiser.

https://philanthroper.com/deals/autism-science-foundation

“You can make a big difference with money placed in the right scientific hands.”

– Alison Singer, Autism Science Foundation

It’s Autism Awareness Month. We know a lot and a little about it. We know it’s a development disorder affecting about 1:88 people. We know it affects boys four times more than girls. We know it can make simple communication and social interactions impossibly difficult for those who have it.

We don’t know “the cause,” but we strongly suspect a large genetic component since identical twins will usually share a diagnosis.

We do know we need to learn more.

The Autism Science Foundation is a new group of parents and doctors united to fund the freshest, most exciting ideas to track down the causes of autism and develop evidence-based treatments.

And they’re really good at leveraging small grants to young, driven researchers – like doctoral students – to explore promising new ideas.

“That first grant can make a huge difference,” explains President Alison Singer. “That’s the money that’s dried up from the federal government. That’s what makes or breaks someone’s career.”

It’s a smart approach: don’t write the biggest checks, just try to write the most important ones. Fund a researcher just enough to explore an idea and gather preliminary data. Then, with this germinating seed of science, a researcher can apply for a larger grant somewhere else to continue the work.

And sometimes, most of the legwork of this research has been completed in the umbrella of another study – there’s just no way to see it through.

“You’ll have a student working on another grant who says, ‘wow, we should also be looking at this function, or this particular protein,'” explains Singer. “That only takes a little bit of extra money.”

Given the ASF’s focus on young, driven minds, it’s not surprising that they themselves are a hot startup in the world of autism nonprofits. Nor is it surprising that they’ve already funded successful research at Johns Hopkins.

That said, they can only do what they do by raising money.

“We run this foundation on a shoestring,” says Singer. “At the end of the year, and we write those grant checks and the treasury goes down to zero. The money does not do anyone any good sitting in Citibank.”

ASAN’s Ethical, Legal and Social Implications of Autism Research Symposium Goes Live

10 Apr

The Autistic Self Advocacy Network (ASAN) hosted a symposium on the Ethical, Legal and Social Implications of Autism Research recently. They are now making it available online. See the message below:

Dear Friends:

This week, the media reported that over $1 billion has been spent over the course of the last decade on autism research funding. During a time of constant budget cuts and increasing fiscal pressures on government, this is an astonishing sum. What have we purchased for this investment? How successful has the autism research agenda been in making the American dream a reality for Autistic people and our families? Has our society discussed the ethical, legal and social consequences of how autism research findings may be used? We think these questions are worth asking, and with your help, we think it is past time to get more people involved in the discussion.

Last December, the Autistic Self Advocacy Network joined with the Harvard Law Project on Disability and the Petrie-Flom Center for Health Law Policy, Biotechnology and Bioethics to hold a symposium on the Ethical, Legal and Social Implications (ELSI) of Autism Research. Supported by a grant from the Administration on Developmental Disabilities, the ASAN ELSI Symposium served as the launching point for a robust conversation about changing the way our society approaches autism research. From our partnership with federal research funders to get self-advocates on grant review panels to growing attention to ethical issues on topics like prenatal testing, self-determination in service-provision and more, the need to introduce values into our national autism research dialogue remains stronger than ever.

Over the course of the month of April, we will be releasing captioned videos of December’s ELSI Symposium. The first is already available on our YouTube channel. You can help us get the word out by watching it alone or with your friends and colleagues, sharing it on facebook and twitter, and starting to talk about these things in your own community. The time has come for our voices to be heard.

Nothing About Us, Without Us!
Ari Ne’eman
President
Autistic Self Advocacy Network

Maternal Metabolic Conditions and Risk for Autism and Other Neurodevelopmental Disorders

9 Apr

A study from the U.C. Davis MIND Institute was published today in the journal Pediatrics: Maternal Metabolic Conditions and Risk for Autism and Other Neurodevelopmental Disorders. The link is to the abstract, but the full paper is available free for download.

The paper is part of the CHARGE Study. (CHARGE: Childhood Autism Risks from Genetics and the Environment). The study looked for increased risk of a child being diagnosed autism if the mother had metabolic conditions during pregnancy. The metabolic conditions studied were diabetes, hypertension and obesity. They found a possibly heightened risk of autism for these pregnancies. I wrote a more in-depth summary which is available at the Autism Science Foundation blog .

Woot! Autistics and Thinking Person’s Guide to Autism editor quoted in New York Times

8 Apr

A story out today by Amy Harmon of the New York Times, The Autism Wars, takes on some of the discussion ongoing about the new prevalence numbers out from the CDC. It is well worth the read.

What caught my eye, as one could tell from the title of this article, are paragraphs like these:

But Zoe Gross, 21, whose autism spectrum disorder was diagnosed at age 4, says masking it can take a steep toll. She has an elaborate flow chart to help herself leave her room in the morning (“Do you need a shower? If yes, do you have time for a shower?”). Already, she had to take a term off from Vassar, and without her diagnosis, she says, she would not be able to get the accommodations she needs to succeed when she goes back.

and

Those numbers are, of course, dependent on the definition of autism — and the view of a diagnosis as desirable. For John Elder Robison, whose memoir “Look Me in the Eye” describes his diagnosis in middle age, the realization that his social awkwardness was related to his brain wiring rather than a character flaw proved liberating. “There’s a whole generation of people who grew up lonelier and more isolated and less able to function than they might have been if we had taken steps to integrate them into society,” he said.

and:

“The term has become so diffuse in the public mind that people start to see it as a fad,” said Emily Willingham, who is a co-editor of “The Thinking Person’s Guide to Autism.” “If we could identify individual needs based on specific gaps, instead of considering autism itself as a disorder, that would be preferable. We all have our gaps that need work.”

In the past, many media outlets would (a) fail to seek autistic input and (b) seek input from autism parents with rather strong political agendas. Amy Harmon has been writing about autism for the Times recently and has articles focused on autistics, so I am not surprised by the tone of this article. But I do see this as a step forward in American Media coverage of autism news.

(note: I know three editors from the Thinking Person’s Guide team and have met Mr. Robison).

Autism Science Foundation live chat with Kevin Pelphrey Friday 12noon eastern time

5 Apr

The Autism Science Foundation will host live interviews with scientists and policy makers during the month of April (Autism Awareness Month). These will be hosted on their facebook page. These will be in a chat format where, as ASF puts it:

“Have questions for an autism researcher? Join us for a live, online chat tomorrow at 12PM ET where YOU can interview Kevin Pelphrey of the Yale Child Study Center.”

The interview/chat with Prof. Pelphrey will be held tomorrow, Friday April 5, at noon eastern time on the Autism Science Foundation facebook page.

Here’s more on Prof. Pelphrey:

Work in Dr. Pelphrey’s laboratory focuses on discovering brain mechanisms underlying the development of different aspects of social cognition including social perception (the initial stages of evaluating the intentions and goals of others by analysis of biological motion cues), theory of mind (the ability to make inferences about the mental states of others), and the perception and regulation of emotion. This work employs cognitive neuroscience methods including functional and structural magnetic resonance imaging, diffusion tensor imaging, imaging genetics, visual scanpath recordings, and virtual reality techniques.

The laboratory conducts studies focused on fundamental questions regarding the typical and atypical development of social cognition in children with and without autism spectrum disorders and other neurodevelopmental disorders. By studying the normal ontogeny of the brain mechanisms underlying social cognition and the abnormal development of these mechanisms in children with autism and other neurodevelopmental disorders, the Pelphrey laboratory is working to uncover the building blocks for complex, multi-faceted, social cognitive abilities.

Dr. Pelphrey has received a Scientist Career Development Award from the National Institutes of Health, a John Merck Scholars Award for his work on the biology of developmental disorders, and the American Psychological Association’s Boyd McCandless Award for distinguished early career theoretical contributions to Developmental Psychology. His research program is funded by the National Institutes of Health, the Simons Foundation, Autism Speaks, and the National Science Foundation.

The 2013 U.S. budget fails to fulfill the promise to fund IDEA

5 Apr

Part of President Obama’s platform when he was campaigning 4 years ago was to fully fund the Federal commitment to special education. On average, a special education student requires about twice the funding as a regular education student. The Federal government made a commitment to pay states 40% of the costs of special education, but has never lived up to that commitment. Typically, the Federal contribution to IDEA is about 17%.

When he campaigned, Mr. Obama’s platform included “Fully Funding the Individuals with Disabilities Education Act”:

Fully Funding the Individuals with Disabilities Education Act: Barack Obama has been a strong and consistent advocate for fully funding the Individuals with Disabilities Education Act (IDEA). Congress promised to shoulder 40 percent of each state’s “excess cost” of educating children with disabilities, but it has never lived up to this obligation. Currently, the federal government provides less than half of the promised funding (17 percent). Children are being shortchanged, and their parents are forced to fight with cash-strapped school districts to get the free and appropriate education the IDEA promises their children. Fully funding IDEA will provide students with disabilities the public education they have a right to, and school districts will be able to provide services without cutting into their general education budgets. In addition to fully funding IDEA, Barack Obama and Joe Biden will ensure effective implementation and enforcement of the Act.

The 2011 proposed budget by Mr. Obama had this language (as I noted in 2010):

The $12.8 billion request for Special Education programs focuses on improving educational and early intervention outcomes for children with disabilities. For the Grants to States program, the Administration is requesting $11.8 billion, an increase of $250 million over the 2010 appropriation, to maintain the Federal contribution toward meeting the excess cost of special education at about 17 percent of the national average per pupil expenditure (APPE), and provide an estimated average of $1,750 per student for about 6.7 million children ages 3 through 21. Funding for the Grants for Infants and Families and Preschool Grants programs would be maintained at their 2010 levels

Which kept funding levels at about the same 17%, not the 40% level committed

For the 2013 budget, Mr. Obama proposes:

Increase Funding for the Education of Children with Disabilities. The Budget provides $11.6 billion for the Individuals with Disabilities Education Act (IDEA) Grants to States to provide a high quality education and help offset State and local education costs for children with disabilities. The Budget also provides a $20 million, or 5 percent, increase for the IDEA Infants and Families Program to provide the youngest children a good start. In addition, the Budget provides $30 million, a $28 million increase over 2012, for PROMISE (Promoting Readiness of Minors in SSI), a four agency joint pilot program, to fund and evaluate innovative approaches to improving outcomes of children receiving Supplemental Security Income and their families.

Yes, $11.6B. Less than the 2011 budget amount of $11.8B and, again, not the 40% of the campaign promise.

The intent of special education legislation has always included Federal funding for the states. What we now call IDEA (the Individuals with Disabilities in Education Act) started out as the “Education For All Handicapped Children Act“, which, itself, is the short name for the bill. The full name for the bill was: “A bill to provide financial assistance to the States for improved educational services for handicapped children.” Pretty clear there.

But congress gave themselves an out. Two outs, really. The summary of the bill states:

Education for All Handicapped Children Act – Extends the provisions of the Education of the Handicapped Act through fiscal year 1977 and authorizes appropriations for such years.

And there you see one of the “outs” the government has with not paying their full commitment. The law “authorizes appropriations”. In other words, they give themselves permission to add it to the budget–but they don’t *require* that it be added to the budget. It’s common language (as I recall, “authorizing appropriations” is in the Combating Autism Act as well).

Here’s the second “out” the legislature used. In the original version of the bill (House Resolution 7217) the law read:

Provides that the Commissioner of Education shall, in accordance with provisions of the Education of the Handicapped Act, make payments to State educational agencies for grants made for assistance in providing full educational opportunity to all handicapped children. States that such allotments shall be in an amount equal to the product of the number of handicapped children in the school district of the local educational agency who are enrolled in programs of free appropriate public education meeting the criteria established in this Act, and 50 percent of the average per pupil expenditure in public elementary and secondary schools in the United States.

They were going to pay 50% of the cost of special education. (special education funding is about twice that of regular education. So by granting the states an additional 50% per special ed student, they are paying 1/2 the funding difference). But the House version of the law was tabled in favor of the senate law

States that the maximum amount of the grant to which a State is entitled under such Act shall equal the number of handicapped children aged three to twenty-one, who are receiving special education in such State, multiplied by a percentage of the average per pupil expenditure in public elementary and secondary schools in the United States. Increases such percentage from 5 to 40 percent by 1982.

While the law is promoted as committing to ramp up the Federal contribution to 40%, congress only committed themselves to a “maximum” of 40%.

Mr. Obama isn’t the first to acknowledge that we have not lived up to our obligation, our commitment. For example, House Resolution 976 in 2001 was the “IDEA Keeping Our Commitment Act of 2001” had the goal “To authorize appropriations for the Individuals with Disabilities Education Act to achieve full funding in fiscal year 2002 and fiscal year 2003, and for other purposes.” It died in committee. As did the “Keeping Our Promises to Special Education Act of 2001″ or the “Keep Our PACT Act” or the “IDEA Full Funding Act” and many other attempts to fulfill the promise.

So congress made the commitment but they gave themselves the ability to dodge that commitment. Many, including President Obama, have recognized that a promise is a promise. They recognize that congress’ stated goal 37 years ago was “A bill to provide financial assistance to the States for improved educational services for handicapped children”. From Mr. Obama’s campaign platform quoted above:

Fully Funding the Individuals with Disabilities Education Act: Barack Obama has been a strong and consistent advocate for fully funding the Individuals with Disabilities Education Act (IDEA). Congress promised to shoulder 40 percent of each state’s “excess cost” of educating children with disabilities, but it has never lived up to this obligation.

With the budget for the final year of Mr. Obama’s first term submitted, we as a people are still not living up to the promise, the obligation. Mr. Obama included a one-time boost for special education in the economic stimulus package. While this is highly disappointing, the sad fact is that should Mr. Obama not be re-elected, the chances for fully-funded special education will be even worse.

Spontaneous Gene Glitches Linked to Autism Risk with Older Dads

4 Apr

Below is a press release from the National Institutes of Health (NIH) in the U.S.. on recently published studies on autism risk. These are the studies mentioned by NIMH Director and IACC chair Thomas Insel in his article “The New Genetics of Autism – Why Environment Matters“.

Spontaneous Gene Glitches Linked to Autism Risk with Older Dads
Non-Inherited Mutations Spotlight Role of Environment – NIH-Supported Study, Consortium

Researchers have turned up a new clue to the workings of a possible environmental factor in autism spectrum disorders (ASDs): fathers were four times more likely than mothers to transmit tiny, spontaneous mutations to their children with the disorders. Moreover, the number of such transmitted genetic glitches increased with paternal age. The discovery may help to explain earlier evidence linking autism risk to older fathers.

The results are among several from a trio of new studies, supported in part by the National Institutes of Health, finding that such sequence changes in parts of genes that code for proteins play a significant role in ASDs. One of the studies determined that having such glitches boosts a child’s risk of developing autism five to 20 fold.

Taken together, the three studies represent the largest effort of its kind, drawing upon samples from 549 families to maximize statistical power. They reveal sporadic mutations widely distributed across the genome, sometimes conferring risk and sometimes not. While the changes identified don’t account for most cases of illness, they are providing clues to the biology of what are likely multiple syndromes along the autism spectrum.

“These results confirm that it’s not necessarily the size of a genetic anomaly that confers risk, but its location – specifically in biochemical pathways involved in brain development and neural connections. Ultimately, it’s this kind of knowledge that will yield potential targets for new treatments,” explained Thomas, R. Insel, M.D., director of the NIH’s National Institute of Mental Health (NIMH), which funded one of the studies and fostered development of the Autism Sequencing Consortium, of which all three groups are members.

Multi-site research teams led by Mark Daly, Ph.D., of the Harvard/MIT Broad Institute, Cambridge, Mass., Matthew State, M.D., Ph.D., of Yale University, New Haven, Conn., and Evan Eichler, Ph.D., of the University of Washington, Seattle, report on their findings online April 4, 2012 in the journal Nature.

The study by Daly and colleagues was supported by NIMH – including funding under the American Recovery and Reinvestment Act. The State and Eichler studies were primarily supported by the Simons Foundation Autism Research Initiative. The studies also acknowledge the NIH’s National Human Genome Research Institute, National Heart Lung and Blood Institute, and National Institute on
Child Health and Human Development and other NIH components.

All three teams sequenced the protein coding parts of genes in parents and an affected child – mostly in families with only one member touched by autism. One study also included comparisons with healthy siblings. Although these protein-coding areas represent only about 1.5 percent of the genome, they harbor 85 percent of disease-causing mutations. This strategy optimized the odds for detecting the few spontaneous errors in genetic transmission that confer autism risk from the “background noise” generated by the many more benign mutations.

Like larger deletions and duplications of genetic material previously implicated in autism and schizophrenia, the tiny point mutations identified in the current studies are typically not inherited in the conventional sense – they are not part of parents’ DNA, but become part of the child’s DNA. Most people have many such glitches and suffer no ill effects from them. But evidence is building that such mutations can increase risk for autism if they occur in pathways that disrupt brain development.
State’s team found that 14 percent of people with autism studied had suspect mutations – five times the normal rate. Eichler and colleagues traced 39 percent of such mutations likely to confer risk to a biological pathway known to be important for communications in the brain.

Although Daly and colleagues found evidence for only a modest role of the chance mutations in autism, those pinpointed were biologically related to each other and to genes previously implicated in autism.

The Eichler team turned up clues to how environmental factors might influence genetics. The high turnover in a male’s sperm cells across the lifespan increases the chance for errors to occur in the genetic translation process. These can be passed-on to the offspring’s DNA, even though they are not present in the father’s DNA. This risk may worsen with aging. The researchers discovered a four-fold marked paternal bias in the origins of 51 spontaneous mutations in coding areas of genes that was positively correlated with increasing age of the father. So such spontaneous mutations could account for findings of an earlier study that found fathers of boys with autism were six times – and of girls 17 times – more likely to be in their 40’s than their 20’s.

“We now have a path forward to capture a great part of the genetic variability in autism – even to the point of being able to predict how many mutations in coding regions of a gene would be needed to account for illness,” said Thomas Lehner, Ph.D., chief of the NIMH Genomics Research Branch, which funded the Daly study and helped to create the Autism Sequencing Consortium. “These studies begin to tell a more comprehensive story about the molecular underpinnings of autism that integrates previously disparate pieces of evidence.”

References
Sanders SJ, Murtha MT, Gupta AR, Murdoch JD, Raubeson MJ, Willsey AJ, Ercan-Sencicek AG, DiLullo NM, Parikshak NN, Stein JL, Walker MF, Ober GT, Teran NA, Song Y, El-Fishawy P, Murtha RC, Choi M, Overton JD, Bjornson RD, Carriero NJ, Meyer KA, Bilguvar K, Mane SM, Sestan N, Lifton RP, Günel M, Roeder K, Geschwind DH, Devlin B, State MW. De novo mutations revealed by whole-exome sequencing are strongly associated with autism. April 5, 2012. Nature.
O’Roak BJ, Vives L, Girirajan S, Karakoc E, Krumm N, Coe BP, Levy R, Ko A, Lee C, Smith JD, Turner EH, Stanaway IB, Vernot B, Malig M, Baker C, Reilly B, Akey JM, Borenstein E, Rieder MJ, Nickerson DA, Bernier R, Shendure J, Eichler EE. Sporadic autism exomes reveal a highly interconnected protein network of de novo mutations. Nature. April 5, 2012.
Neale BM, Kou Y, Liu L, Ma’ayan A, Samocha KE, Sabo A, Lin CF, Stevens C, Wang LS, Makarov V, Polak P, Yoon S, Maguire J, Crawford EL, Campbell NG, Geller ET, Valladares O, Schafer C, Liu H, Zhao T, Cai G, Lihm J, Dannenfelser R, Jabado O, Peralta Z, Nagaswamy U, Muzny D, Reid JG, Newsham I, Wu Y, Lewis L, Han Y, Voight BF, Lim E, Rossin E, Kirby A, Flannick J, Fromer M, Shair K, Fennell T, Garimella K, Banks E, Poplin R, Gabriel S, DePristo M, Wimbish JR, Boone BE, Levy SE, Betancur C, Sunyaev S, Boerwinkle E, Buxbaum JD, Cook EH, Devlin B, Gibbs RA, Roeder K, Schellenberg GD, Sutcliffe JS, Daly MJ. Patterns and rates of exonic de novo mutations in autism spectrum disorders. Nature. April 5, 2012.
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The mission of the NIMH is to transform the understanding and treatment of mental illnesses through basic and clinical research, paving the way for prevention, recovery and cure. For more information, visit the NIMH website.
About the National Institutes of Health (NIH): NIH, the nation’s medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit the NIH website.

Thomas Insel: The New Genetics of Autism – Why Environment Matters

4 Apr

Thomas Insel is the director of the National Institute of Mental Health (NIMH) and the chair of the Interagency Autism Coordinating Committee (IACC) in the U.S..

His article can be found here (The New Genetics of Autism – Why Environment Matters) and I have quoted it in full bellow. (As a government publication I feel that it is appropriate to use the entire piece):

Last week’s autism news was about prevalence. The CDC reported a 78 percent increase in autism prevalence since 2002. This week’s autism news is about genetics—three papers in Nature describe new genes associated with autism. For many people, these two stories seem contradictory or, at best, unrelated. Increasing prevalence suggests environmental factors like chemicals and microbes changing over the past decade, whereas genes change over generations. Why is anyone looking for genetic causes when there is such a rapid increase in prevalence? Shouldn’t every research dollar be invested in finding the environmental culprit rather than searching for rare gene variants?

The simple answer is that some autism is genetic. Autism, like schizophrenia and mood disorders, includes many syndromes. Indeed, we should probably speak of the “autisms.” Some of these autisms are single gene disorders, such as Fragile X, tuberous sclerosis, and Rett syndrome. While these rare genetic disorders account for less than 5 percent of children within the autism spectrum, children with any of these disorders are at high risk for autism, roughly a 30-fold higher risk than the general population and higher than any of the other known risk factors. Recent genomics research has discovered that many children diagnosed within the autism spectrum have other genetic mutations that have not yet been designated as named syndromes. Each of these mutations is rare, but in aggregate they may account for 10 – 20 percent or more of what we have been calling the autisms.1

The new papers published today in Nature use an approach called whole exome sequencing, mapping every base of DNA across the exome—the 1.5 percent of the genome known to code for protein. The three research groups are members of the Autism Sequencing Consortium (ASC), an international team of autism genetics researchers. All three look for de novo or spontaneous mutations, changes in DNA sequence that are not found in either parent. Recent sequencing studies in the general population have demonstrated that each of us diverges genomically from our parents — the process of reproduction introduces variation even beyond the random mixture of the genomes we inherit from mom and dad. People with autism and schizophrenia are far more likely to have large de novo copy number variants, sometimes a million bases of DNA that are abnormally duplicated or deleted and not found in either parent.
These new papers go beyond the previous discovery of de novo copy number variants to identify de novo single base changes associated with autism. This is tough sailing because there are so many of these changes in all of us and most of these single base changes have no impact. These studies tried to improve the odds of success by focusing on individuals from families with no one else affected (these are called “simplex” families), and sometimes comparing the individual with autism to a sibling without autism. The results are intriguing.

There is no breakthrough or single gene that is a major new cause of autism. But the role of genetics becomes even more evident when these single base changes are considered. For instance, an individual with autism is nearly 6-fold more likely to have a functional variant in genes expressed in the brain. Sanders et al. estimate as many as 14 percent of affected individuals have such a risk variant.2 This 14 percent is in addition to the 10–20 percent with a large copy number variant or identified genetic syndrome. O’Roak et al. find that 39 percent of these variants are related to a specific biochemical pathway, important for brain signaling.3 And Neale et al., while cautioning that the net effect of all of these changes still leave much of the risk for autism unexplained, note the roles of a few specific genes as genuine risk factors.4

Stepping back from this flood of genomic information, what is most important? First, these reports along with previous publications confirm that genetic risk is both complex and substantial. While individual genes appear to confer limited risk, the aggregate effect of spontaneous coding mutations across the genome is now estimated to increase the risk of autism by 5–20-fold.4 Complex genetics does not mean modest effects.

Second, the kinds of small and large genetic changes associated with autism are common in everyone. Risk is conferred not by the size of the mutation or the number of mutations (we all have many) but by the location. Increasingly, we see that interference with the genes involved in development of synapses confer risk; a similar change upstream or downstream does not.
A third point takes us back to the questions we started with. It is important to understand that de novo mutations may represent environmental effects. In other words, environmental factors can cause changes in our DNA that can raise the risk for autism and other disorders. One of these papers reports that spontaneous changes are four times more likely to show up in paternally inherited DNA and are correlated with paternal age.2 The father’s germline, his sperm cells, turn over throughout the lifespan. Presumably, with advancing paternal age, there are a greater number of spontaneous mutations and a greater likelihood that some of these will affect risk genes. Environmental factors and exposures can cause sperm cells to develop mutations that are not found in the father’s somatic, or body cell, DNA, but these new, spontaneous mutations can be passed to the next generation, raising the risk for developing autism. In the initial report of the relationship between autism and paternal age, boys with autism were 6-fold more likely to have a father in his 40s vs his 20s. In girls with autism, this difference went up to 17-fold.5 Paternal age has, of course, increased in the past few decades. This does not explain the increasing prevalence of autism, but it may contribute.

Is autism genetic or environmental? These new studies suggest it can be both. Genetics will not identify the environmental factors, but it may reveal some of the many syndromes within the autism spectrum (as in other neurodevelopmental disorders), it can define risk (as in other medical disorders), and it should yield clues to the biology of autism (revealing potential targets for new treatments). These three new papers on spontaneous mutations are an important milestone in a long journey. In parallel we need to find environmental factors, recognizing that there will be many causes for the autisms and many roads to find them.

Finally, an unavoidable insight from these new papers is that autism even when genetic may be spontaneous and not inherited in the sense that one or both parents carry some reduced form of the syndrome. Perhaps this insight will finally reduce the “blame the parents” legacy perpetuated for too long in the absence of scientific evidence.

References
1Geschwind DH. Genetics of autism spectrum disorders. Trends Cogn Sci. 2011 Sep;15(9):409-16. Epub 2011 Aug 18. PubMed PMID: 21855394.1
2Sanders SJ, Murtha MT, Gupta AR, Murdoch JD, Raubeson MJ, Willsey AJ, Ercan-Sencicek AG, DiLullo NM, Parikshak NN, Stein JL, Walker MF, Ober GT, Teran NA, Song Y, El-Fishawy P, Murtha RC, Choi M, Overton JD, Bjornson RD, Carriero NJ, Meyer KA, Bilguvar K, Mane SM, Sestan N, Lifton RP, Günel M, Roeder K, Geschwind DH, Devlin B, State MW. De novo mutations revealed by whole-exome sequencing are strongly associated with autism. April 5, 2012. Nature.
3O’Roak BJ, Vives L, Girirajan S, Karakoc E, Krumm N, Coe BP, Levy R, Ko A, Lee C, Smith JD, Turner EH, Stanaway IB, Vernot B, Malig M, Baker C, Reilly B, Akey JM, Borenstein E, Rieder MJ, Nickerson DA, Bernier R, Shendure J, Eichler EE. Sporadic autism exomes reveal a highly interconnected protein network of de novo mutations. Nature. April 5, 2012.
4Neale BM, Kou Y, Liu L, Ma’ayan A, Samocha KE, Sabo A, Lin CF, Stevens C, Wang LS, Makarov V, Polak P, Yoon S, Maguire J, Crawford EL, Campbell NG, Geller ET, Valladares O, Schafer C, Liu H, Zhao T, Cai G, Lihm J, Dannenfelser R, Jabado O, Peralta Z, Nagaswamy U, Muzny D, Reid JG, Newsham I, Wu Y, Lewis L, Han Y, Voight BF, Lim E, Rossin E, Kirby A, Flannick J, Fromer M, Shair K, Fennell T, Garimella K, Banks E, Poplin R, Gabriel S, DePristo M, Wimbish JR, Boone BE, Levy SE, Betancur C, Sunyaev S, Boerwinkle E, Buxbaum JD, Cook EH, Devlin B, Gibbs RA, Roeder K, Schellenberg GD, Sutcliffe JS, Daly MJ. Patterns and rates of exonic de novo mutations in autism spectrum disorders. Nature. April 5, 2012.
5Reichenberg A, Gross R, Weiser M, Bresnahan M, Silverman J, Harlap S, Rabinowitz J, Shulman C, Malaspina D, Lubin G, Knobler HY, Davidson M, Susser E. Advancing paternal age and autism. Arch Gen Psychiatry. 2006 Sep;63(9):1026-32. PubMed PMID: 16953005.

A summary of the CDC autism prevalence report

3 Apr

In case you don’t have the time to review the full recent CDC prevalence report but you’d like some more information, I’ve written a summary of the CDC report at the Autism Science Foundation blog. The CDC has provided a lot of analysis in this edition of the prevalence report.

A couple brief side points I’ll make here. Most countries have no autism prevalence studies. There is basically no prevalence information for autism in Africa or South America, for example. And, while it takes a long time between prevalence reports by the CDC, consider this paragraph:

The 14 ADDM sites that provided data for the 2008 surveillance year covered a total population of 337,093 children aged 8 years, which represented 8.4% of the U.S. population of children that age in 2008 (13). A total of 48,247 source records for 38,253 children were reviewed at education and health sources. Of these, the source records of 6,739 children met the criteria for abstraction, which was 17.5% of the total number of children whose source records were reviewed and 2% of the total population under surveillance (range: 1.0% [Alabama]–6.3% [Utah]). During clinician review, 3,820 children (57%) were confirmed as meeting the ASD surveillance case definition (range: 30% [Arkansas]–74% [North Carolina]). The number of evaluations abstracted for each child ultimately identified as having an ASD varied (median: 5; range: 3 [Florida and North Carolina]–10 [Utah].

48,247 records were reviewed. If one gives 10 minutes per document for collection and review, that’s something like three full-time man-years for that effort alone. Yeah, we’d all like the process to go faster. But we all need the report to be as accurate as possible. This is no small task.

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