Genetic Links in Autism
04/29/09 05:30 Filed in: Research
The Chicago Tribune is reporting, in an article dated for today, on a pair of studies reported in the Journal Nature that relate to advances in research on genetic variations in autistic disorder. The entire text of the study article is available at Nature's website for those with advanced training in genetics and/or molecular biology (a group I am most certainly not among).
Information about study size, and design however, which are important components in determining the relative quality of research, are more universal research components. It is notable that this was a fairly good sized study, involving over 5,000 participants with autism spectrum disorders, and a very large control group. Autism diagnoses were made using the ADOS and/or the ADI-R, which would suggest good reliability and consistency in diagnosing autism amongst the participants.
Although the Nature article is appropriately scientifically dense, the Tribune article does provide some interesting information. Overall, the results suggest there are shared similarities in genetic variation between 65% of the people with autism who participated in the study. This essentially means that those 65% of the participants were genetically different than others, and that those differences were the same.
This is an important advance. In other genetically linked disorders researchers have been able to identify the common differences, allowing us to understand how the disorder develops. In people with Down Syndrome, for example, the disorder occurs because the person has an additional 21st chromosome (leading the disorder to also be referred to as Trisomy 21). In Fragile X Syndrome the disorder has been linked to differences in the X chromosome.
Although we have known for some time that many people with autism have genetic differences from the general population, researchers had found that those variations were different from one person to the next.
Some cautions are to be noted here in interpretation of these results. These variations were found in 65% of the study participants, meaning, of course, that they were not found in 35% of the participants. The article in the Tribune also notes that the differences were found in 60% of the study participants who did not have autism (the control) group.
The results are statistically significant, but very different from what we see when we look at other genetic conditions like Down Syndrome. Generally speaking, my understanding is that you would expect to see Trisomy 21 in essentially 100% of people with Down Syndrome. Further, it seems unlikely that you would find that 60% of participants without Down Syndrome also had Trisomy 21. All of this is to say that these results are clearly an important advance, but do not provide nearly the level of explanatory power that we see for other genetic syndromes.
I would expect that we'll see this discussed on NPR's Science Friday this week or next as well. I'd highly recommend watching for that to show up. Science Friday is also available as a podcast (my preferred way to listen) if you are unable to catch it live.
Information about study size, and design however, which are important components in determining the relative quality of research, are more universal research components. It is notable that this was a fairly good sized study, involving over 5,000 participants with autism spectrum disorders, and a very large control group. Autism diagnoses were made using the ADOS and/or the ADI-R, which would suggest good reliability and consistency in diagnosing autism amongst the participants.
Although the Nature article is appropriately scientifically dense, the Tribune article does provide some interesting information. Overall, the results suggest there are shared similarities in genetic variation between 65% of the people with autism who participated in the study. This essentially means that those 65% of the participants were genetically different than others, and that those differences were the same.
This is an important advance. In other genetically linked disorders researchers have been able to identify the common differences, allowing us to understand how the disorder develops. In people with Down Syndrome, for example, the disorder occurs because the person has an additional 21st chromosome (leading the disorder to also be referred to as Trisomy 21). In Fragile X Syndrome the disorder has been linked to differences in the X chromosome.
Although we have known for some time that many people with autism have genetic differences from the general population, researchers had found that those variations were different from one person to the next.
Some cautions are to be noted here in interpretation of these results. These variations were found in 65% of the study participants, meaning, of course, that they were not found in 35% of the participants. The article in the Tribune also notes that the differences were found in 60% of the study participants who did not have autism (the control) group.
The results are statistically significant, but very different from what we see when we look at other genetic conditions like Down Syndrome. Generally speaking, my understanding is that you would expect to see Trisomy 21 in essentially 100% of people with Down Syndrome. Further, it seems unlikely that you would find that 60% of participants without Down Syndrome also had Trisomy 21. All of this is to say that these results are clearly an important advance, but do not provide nearly the level of explanatory power that we see for other genetic syndromes.
I would expect that we'll see this discussed on NPR's Science Friday this week or next as well. I'd highly recommend watching for that to show up. Science Friday is also available as a podcast (my preferred way to listen) if you are unable to catch it live.
