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Archive for December, 2010

Why is autism more common in boys?

December 21, 2010 4 comments

“Got Questions?” is a new weekly feature on our blog to address the desire for scientific understanding in our community.  We received over 3000 responses when we asked what science questions were on your mind. We answered a few here and the Autism Speaks Science staff will address the other themes we received in this weekly post.

In 2009, researchers discovered an autism risk gene on chromosome 17 called CACNA1G that is more common in boys than girls. The gene is partially responsible for regulating the flow of calcium in brain cells. Calcium is very important in transmitting information and having too much of the mineral may cause the overexcitability of neural circuits that we have seen in autism. This is a promising finding, though there have been other suggestions. Some researchers have suggested that females are less vulnerable to developmental disorders because of their neurochemistry. Also, autism risk genes have been found on the X chromosome. Since girls carry two X chromosomes, they have two copies of these genes, and one of the genes may not carry the mutation. This may help to protect them against the effects of an X-linked mutation. Although we don’t have a firm answer yet, the gender imbalance in autism diagnoses is a clue that researchers are pursuing actively.

Are you aware of any research being done on diet and its affect on children w/ autism? If so, what has been learned?

December 21, 2010 3 comments

“Got Questions?” is a new weekly feature on our blog to address the desire for scientific understanding in our community.  We received over 3000 responses when we asked what science questions were on your mind. We answered a few here and the Autism Speaks Science staff will address the other themes we received in this weekly post.

To date, there have only been a few published rigorous clinical trials examining the efficacy of dietary treatment (specifically, the gluten-free, casein-free diet) for improving symptoms of ASD. These have been negative or inconclusive, but were based on very small samples. More recently, Dr. Susan Hyman at the University of Rochester reported the results of a double-blind, randomized trial in which children who were on the diet were challenged with foods containing casein and gluten. Dr. Hyman examined factors such as attention, sleep and the stool of 22 children with ASD both challenged and unchallenged and found no benefit from the diet. Dr. Hyman stressed that her findings don’t rule out the possibility that there may be subgroups of children who benefit. Autism is a very heterogeneous condition. More research is needed.

How can families participate in research studies?

December 21, 2010 Leave a comment

“Got Questions?” is a new weekly feature on our blog to address the desire for scientific understanding in our community.  We received over 3000 responses when we asked what science questions were on your mind. We answered a few here and the Autism Speaks Science staff will address the other themes we received in this weekly post.

Great question! We hope more families wish to get involved in research. One easy way to get started is through an online portal called the Interactive Autism Network (IAN) at ianproject.org. This site allows you to participate in research from your home. You can also find studies and participate in programs supported by Autism Speaks. If you are interested in a clinical trial (which is not just about treatment, but also diagnosis, identifying subtypes, etc.) you can find more information at clinicaltrials.gov.

Any link between vaccines and autism? Put this issue to rest once and for all, one way or the other?

December 21, 2010 9 comments

“Got Questions?” is a new weekly feature on our blog to address the desire for scientific understanding in our community.  We received over 3000 responses when we asked what science questions were on your mind. We answered a few here and the Autism Speaks Science staff will address the other themes we received in this weekly post.

We really wish it were that simple. Several epidemiological studies have explored whether either the MMR vaccine or thimerosol, a preservative previously used in vaccines, are linked to autism, and these studies have not supported a link. However, these studies were not designed to identify effects in a small population of potentially vulnerable children due to rare genetic and/or medical conditions. We are seeking to understand if vulnerable populations exist, and if so, how we identify them early so they can be protected from public health threats in the safest manner possible. For more information please see our vaccine statement and an interview with Dr. Geraldine Dawson, Autism Speaks’ Chief Science Officer, about vaccines and autism.

Has the rate of autism truly increased in the last 50 years or so or is it just that the classification of autism has gotten broader and as such the prevalence seems larger?

December 21, 2010 4 comments

“Got Questions?” is a new weekly feature on our blog to address the desire for scientific understanding in our community.  We received over 3000 responses when we asked what science questions were on your mind. We answered a few here and the Autism Speaks Science staff will address the other themes we received in this weekly post.

In the last two decades reported autism prevalence has increased by more than 600% and a number of studies have sought to investigate the cause(s) of this dramatic increase in autism prevalence over time. Recent findings suggest that at least a portion of the increase in prevalence can be attributed to changes in diagnostic practices, earlier age of diagnosis, and increased awareness of autism over time. However, converging evidence also suggests that while these factors account for a portion of the increase, they cannot alone explain the dramatic rise in autism prevalence. Thus genetic and/or other environmental factors likely play a role and are the subject of numerous research projects currently supported by Autism Speaks.

Is there empirical evidence that parental age is a contributing factor to giving birth to a child with autism?

December 21, 2010 2 comments

“Got Questions?” is a new weekly feature on our blog to address the desire for scientific understanding in our community.  We received over 3000 responses when we asked what science questions were on your mind. We answered a few here and the Autism Speaks Science staff will address the other themes we received in this weekly post.

A number of recent publications investigating the relationship between parental age and autism have demonstrated that older parents are at increased risk for having a child with autism. This is not surprising since increased parental age is associated with a slightly increased risk for other developmental disorders, as well. Grether, et. al. reported in 2009 that parental age and particularly maternal age is a significant risk factor for autism. The authors found that a 10-year increase in maternal age increased the chances of having a child with autism by 38% and mothers over the age of 40 were at highest risk. Other studies, such as a recent study by Hertz-Piccioto, found that the risk for autism spectrum disorder (ASD) in older mothers was lower than 38%. King and Bearman, et. al. similarly found that older mothers and fathers were at increased risk of having a child with autism with the largest risk among mothers aged 40 and over. Since the risk for ASD is low, the risk for ASD in older mothers, although increased, is still relatively low. The underlying mechanism behind the relationship between increased parental age and risk for autism is currently unknown and under investigation.

Are you finding that autism is increasing at the same/similar pace worldwide? I’ve read about pockets of increased autism in Silicon Valley, CA for example. Wondering if there’s data on a global rate of autism?

December 21, 2010 1 comment

“Got Questions?” is a new weekly feature on our blog to address the desire for scientific understanding in our community.  We received over 3000 responses when we asked what science questions were on your mind. We answered a few here and the Autism Speaks Science staff will address the other themes we received in this weekly post.

While we are seeing converging evidence in the research literature showing that autism prevalence is about 1% in developed countries such as the US and UK, there has yet to be published data on prevalence in low and middle income countries. Autism Speaks is actively trying to change that by funding epidemiologic research of autism prevalence in a number of low and middle income countries around the world including South Korea, Taiwan, Bangladesh, India, and South Africa. Conducting studies in countries where socio-cultural, environmental, and genetic factors may differ from those in the US can allow researchers to compare prevalence rates and examine how those factors may contribute to autism risk.

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