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Archive for November, 2015

B17I3424

ASF Undergraduate Summer Research Grantee Dylan Ritter in the lab of  Dr.Dindot at Texas A&M

I first came in contact with Dr. Dindot at Texas A&M University in the late fall of 2013 when I was a college freshman. I had seen an article published that highlighted his success in creating a mouse model used to mimic the effects of a specific kind of autism spectrum disorder, Duplication 15q Syndrome (Dup 15q). For most people reading that, the article would stand merely as an informative story about some researcher in Texas. For me, that article had a totally different context.

 

My youngest brother, Travis, was diagnosed with Dup15q at the age of two when I myself was only four years old. For as long as I could remember, I had a younger brother that needed help brushing his teeth, could never speak to me, and somehow enjoyed the credits of a movie more than the movie itself. I never questioned it, but I was certainly aware that our family was different from a lot of others. Meeting other families that had children with Dup15q helped me realize this condition extended beyond my five-person family, and that there was research being performed to find therapeutic options and genetic factors behind this condition.

When talking with Dr. Dindot about his research, he surprised me by ensuring me that I would be on the workbench with my own projects doing real research. And that’s exactly how the summer of 2014 was spent. I learned so much about the condition, the laboratory environment, and all of the hard work being done to find answers. I decided that I would like to return to the lab to continue research in the summer of 2015, after my sophomore year. With most of the logistics figured out from the previous summer, I was able to speak with Dr. Dindot more about what was going on in the lab rather than figuring out where his lab was on campus. In discussions about my research, he proposed that I apply for a fellowship through the Autism Science Foundation, since they were eager to support the work of undergraduate researchers interested in autism. On March 9th, I was informed that I had been selected as one of five undergraduates to receive funding for my research. It was such an exciting feeling knowing that I had been chosen by a committee as someone they believe will succeed in research. With that extra motivation, I prepared myself for the summer ahead.

I had a variety of projects going on during my time, but that main one was the classification of one of the mouse models Dr. Dindot had designed. It was set up so that excess gene expression would mimic the effects of the extra chromosomal information present in Dup15q. However, there is a unique system in which a drug could be administered in order to suppress this extra expression. The theory behind it all was that if a mouse had normal gene expression, it should have a normal phenotype without the manifestations of Dup15q. By the end of the project, it was shown that after only three days of this treatment, the excess gene expression was reduced more than 60%, showing a major change between overexpression mice and wild-type mice.

Though this was just the beginning of the project, the hope is that these mice with slightly adjusted drug treatments may eventually reach gene expression comparable with wild-type mice. From there, it is possible to perform further analysis on these mice to see if there are any phenotypic changes that occur when the gene levels change in the mouse. With the amount of progress research has made in the past 20 or 30 years, there’s no way of even being able to guess where autism research will be in the next 20 or 30 years. All I can say is that I have been extremely humbled and honored to have the opportunity to represent the Autism Science Foundation, Texas A&M, and Ole Miss by doing what I love.

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A summary of the recent evidence, by Thomas Frazier, PhD and Stelios Georgiades, PhD.

SG

Stelios Georgiades, PhD

Some family members of people with ASD often share many autism traits, but don’t have or show the number or severity of symptoms needed to be diagnosed. A recent study using the Interactive Autism Network looked at some features of autism in over 5500 individuals, some with multiple siblings with autism, some only one sibling. They wanted to determine if number of siblings with autism or sex of the sibling with autism influenced how these symptoms presented, if at all.

What did the researchers do?

Frazier_Thomas_724336 headshot

Thomas Frazier, PhD

When a family enrolls in the Interactive Autism Network not only do they enter in information about the person diagnosed with autism, they also fill out a form called the Social Responsiveness Scale on all family members. This is a quantitative measure of autism traits. Instead of saying autism: yes-or-no, the scale gives a number that corresponds to the presentation of features. It is used in people with autism, but has also been used to study features of autism of those without a diagnosis. Some people have higher levels than others but most people score around the middle.   The higher the number, the more features of autism that person exhibits. In this study, the analysis consisted of 5515 brothers and sisters, 2858 with ASD and 2657 without ASD. They looked at how autism symptoms occur in male-only ASD-affected families vs. female-only affected families or in families with single vs. multiple cases of ASD. They also looked at the siblings of ASD children who did not have the condition but who had language delay or speech patterns usually seen in children with ASD. The sex of the siblings was also taken into account in the analysis.

What did the researchers find?

The research found that

  • the non-ASD brothers and sisters (siblings) of children with ASD were more likely to show higher levels of symptoms if they were many members of their family with ASD,
  • the non-ASD boys in these families were more likely to have a higher number of symptoms, as were boys with language delay or speech patterns usually seen in children with ASD,
  • the children with ASD in families with several members with ASD had lower levels of symptoms than did the ASD children if they were the only child in the family with the condition, and
  • the likelihood of having more than one child with ASD in a family was higher if that family had female members with ASD, and
  • it is likely that girls need a much greater number of the genes related to ASD to produce the symptoms needed to warrant a diagnosis of ASD.

 What does this mean?

Both the sex and the number of children with ASD in a family strongly influence the risk of their non-ASD siblings having a high number of autism symptoms.  This again, links genetics to the causes of autism. These preliminary data suggest that siblings from certain families may have a higher likelihood of having children with ASD, but it is too early to base any family planning decisions on this data. It also emphasizes that girls have a higher genetic load, and that girls may be in some way, protected against some symptoms of autism.

 

References:

Frazier TWYoungstrom EAHardan AYGeorgiades SConstantino JNEng C. (2015)  Quantitative autism patterns recapitulate differential mechanisms of genetic transmission in single and multiple incidence families.  Molecular Autism, 6:58.  Full text here:  http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4623917/

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