New Gene Studies Uncover Why Autism Symptoms Vary Widely
Autism, or autistic disorder, is a wide range of problems that occur when the brain develops differently. Such abnormal development results in a struggle for autistic children to perceive the world in the same way that other people do. Our brain is responsible for deciphering what we see, hear, breath, touch, taste, and experience. It then uses that information to send nerve signals to the appropriate muscles and organs, with instructions on how to respond. But with autism, the brain struggles to fulfill this vital role, and as such, it becomes very difficult to listen, talk, learn, and play. However, though 1 out every 88 kids is diagnosed with 'autism', their symptoms vary significantly in character and severity.
Some autistic children suffer from severe speech impairments, while others can talk easily but have a hard time processing what other people are thinking and feeling. Symptoms of the disorder may also include repetitive twirling or rocking movements, a habit of speaking in a singsong voice about favorite things, or a tendency to refer to themselves by their name instead of "I" or "me." In other words, every autistic child is unique in his or her way, which is why doctors often state, “If you’ve seen one kid with autism, you’ve seen one kid with autism,” - this means that it's difficult to come to any general conclusion by observing just a few patients.
The biggest impediments to determining the exact genetic cause of this increasingly common disorder has been the lack of sufficient technology and a shortage of families willing to be tested. But that is starting to change. With advances in genetics that have allowed scientists to look at the DNA in more detail, and widespread collaboration between experts, scientists now know that the reason for the disparities in behavior is because there are hundreds or possibly even a thousand or more different genetic subtypes of autism.
Among the many researchers trying to get to the root of this common disorder is Evan Eichler, professor of genome science at the University of Washington. He gained access to the medical histories of over 6,000 autistic patients, both kids and adults, by collaborating with genetic scientists in Australia, Belgium, China, the Netherlands, and Sweden.
From this pool, his team identified mutations in about 200 genes that are linked to autism. These people were then invited to the University of Washington or a center nearby, for several thorough examinations and medical tests, as well as measurements of head and facial proportions, and linguistic motor skills. The information was used to create a profile for each person. Since previous studies have found that people with the same mutations display similar autistic symptoms and in many cases also look similar, each profile was then compared with others and subgroups were formed. Then began the work of identifying the gene mutation for each group.
Raphael Bernier, one of the researchers involved in the clinical study says that once they grouped the patients it was easy to see the similarities, even physically. An example he gives is of two children who both had wide-set eyes, a large head and difficulty falling asleep. Bernier stated "They were so alike that they could have been siblings. We started to say, there's a pattern here; there's a trend here." Indeed, the trend was discovered in 13 other individuals. All were found to have the mutation in the gene CHD8, which coils DNA inside the nucleus of a cell.
Other types of mutated genes that were discovered include ADNP, which results in digestive problems, NHE6, which causes a delay in neuronal development, and DYRK1A, which leads to intellectual disability and small heads. While identifying the genes associated with the various symptoms has certainly helped, it has raised a new dilemma for researchers who had previously believed that all types autism could be treated in the same way.
Though scientists are pairing up to find specific treatments to each subcategory of autism, the research is still in the early stages of development. Hence, while molecular diagnosis has been a success, cure still remains a little elusive.
Regardless, parents of autistic children have at last been granted a little relief; with definitive scientific research that points to spontaneous mutations as the cause of autism, parents can stop feeling guilty about being responsible for their child’s disorder. Furthermore, researchers have begun to link families with children that have the same subcategory of autism. Such connections have provided hope and support to those who struggle with the daily challenges that autism entails and also allowed them to share experiences of unconventional treatments.
For those a little unsure of what genes are and how they help with our daily functions here is a brief tutorial. Genes are located on DNA, a special molecule within each cell that is charged with running the daily tasks of the body. Each gene functions as a command, possessing the instructions on what or how the body should carry out its daily activities. In many instances several genes have to work together to carry out a specific function. For example, in order to engage in normal social interactions, the body needs hundreds of genes to function in synch - ranging from those that help you listen to the words being spoken, to those that help you respond with the right tone of voice. A mutation in even one of those genes could result in some kind of social impairment, a trait that is fairly common in people suffering from autism.
Resources: Wired.com, ninds,nih.gov,npr.org
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