The results of a new study published recently in the online edition of the American Journal of Psychiatry show that there is a genetic connection in families with one child who has autism and the other child who suffers from a specific language impairment. The study is led by a research team from the Rutgers University in collaboration with the Nationwide Children’s Hospital in Ohio, United States.
The main author of the study, professor Linda Brzustowicz, notes that the genes responsible for both the oral and the written language impairments can cause similar behavioral impairments. The regions of the chromosomes involved are 15q23-26 and 16p12. Brzustowicz reports that the similar characteristics can lead to the onset of autism for one child, while the other child will only develop a certain level of language impairment.
Specific language impairment is considered to be one of the most common learning disabilities, affecting approximately 7% of the children worldwide. However, specific language impairment isn’t considered as an autism spectrum disorder. In the United States alone, autism affects almost one in 90 children, in a 5:1 ration for boys:girls. Approximately 50% of the affected children suffer from a certain degree of language impairment.
Brzustowicz reports that in collaboration with Christopher Bartell, they tried to discover whether or not there are any genetic factors that connects the language impairment with autism. Brzustowicz says that the current study plays an important role due to the fact that in order to understand autism, the genes involved in its onset and development must be discovered.
Although researchers believe that there is a large number of genes that are responsible for increasing the risk of autism onset, both Brzustowicz and her team have been trying to identify a genetic pattern in the studies families. 79 families, the majority of whom are from Pennsylvania and New Jersey, underwent a series of extensive tests. All of the families have one child suffering from autism and at least one other child that suffers from a degree of language impairment. In addition to the blood samples that were taken for genetic tests, all of the family members were thoroughly tested in order to asses their grammar, language, and vocabulary skills.
The results of the tests show that specific behavioral characteristics can be seen within each family, in addition of the specific shared DNA patterns. Furthermore, the research team discovered very strong evidence that there is a genetic connection in the area of repetitive behavior, social interaction skills, obsessive-compulsive behaviors, and other symptoms that are frequently associated with autism.
According to professor Brzustowicz, the next step of the study will be to perform a genome sequencing test on all of the subjects of the study in order to create a comparison and investigate if there are some specific genes or genetic mutations that are common for all the subjects. Professor Brzustowicz and her team have been investigating the genetic links associated to autism for the past 10 years. Recently, her team was awarded with a $2.2 million grant. As of now, their study is opened for more families with autism, and will take place for another 4 years.