By Jo Lyons

Over the past two decades, the number of children born with autism has increased significantly, from approximately 4 to 40 cases per 10,000. Problem behaviors that are associated with autism include problems in language and perceptual motor development; dysfunctional reality testing; and difficulty functioning in social interactions (Butcher, et al., 2010). Although the majority of the studies conclude that it is a genetic disorder that affects central nervous system, scientists and researchers are still unable to pinpoint the exact causes of this disorder. In this current paper, genetic mutations and parental age is investigated.

In the 1940s, Leo Kanner discovered autism. It was believed that parents of children with autism were not loving, cold, and that autism was a result of bad parenting. He called them “emotional refrigerators”, but this belief was debunked throughout the years (Seitler, 2010). In more recent years other factors that have been thought to be the cause of autism have been quite controversial from the beliefs that particular chemicals found in vaccinations were involved to the age of the parents. Although the theory that vaccinations caused autism have been ruled out over the years, researchers still have had a difficult time ruling out the age of the parents during reproduction. It is hypothesized that the paternal age of the parents, and particular genetic mutations are the leading causes of autism. The following literature reviews will attempt to support these hypotheses.

One theory of the cause of autism is the factor of older reproduction age. Continuous and categorical measures of autistic spectrum disorders, autistic traits, and autistic similarities were calculated and compared over paternal age categories. The study supported the hypothesis by showing an elevated risk of autistic spectrum disorder in both the studies of youngest and oldest fathers. Similarities of autism increased with higher paternal age in both monozygotic and dizygotic twins. “mechanisms influencing the trajectories might differ between older and younger fathers” (Lundstrom, et al., 2010). Concluding that the age of the fathers determined particular risks for autism.

Another study conducted by Marissa King, Christine Fountain, Diana Dakhlalla, and Peter Bearman attempted to answer the question of whether or not the higher maternal or paternal age independently was associated to the risk of autism? They studied the risk of autism relating to maternal and paternal age across successive cohorts. This supported the hypothesis that the risk of having a child born with autism is higher because of paternal age more than maternal age (King, Fountain, Dakhlallah, & Bearman, 2009)

Another article that discusses a study conducted by scientist Stephen Scherer and others that answers the question, do genetics play a role in the risks of autism? A group of international researchers analyzed the genetic makeup of 99 individuals with autism and 1,287 individuals without autism. They found that over 5,000 copy number variants in the individuals with autism were often missing parts of DNA. The group found that there was more than one spot in the genome where large portions of DNA were missing in those people who had autism. One particular gene that was linked to autism in this study was DDX53-PTCHD1, which is on the X chromosome. Women who are missing the gene on one of their X chromosomes usually carry a healthy version of the gene on the other X chromosome to make up for the deleted copy. However, if a women passes this X chromosome with the missing gene onto her son, he will not have a healthy copy of the gene and will most likely get autism (Saey, 2010).

A different group of international researchers working under The Autism Genome Project, which consists of 120 scientists from more than 60 different institutions, searched for the genetic factors that increase the risks for autism. They attempted to answer the question: can the genes that give rise to autism be identified? Involved in this study were scientists from Lucile Packard Children’s Hospital and Stanford University. Joachim Hallmayer, M.D., associate professor of Psychiatry, and an individual from the Stanford Autism Center at Packard Children’s Hospital, all noted the significance of the findings. An analysis of high-density genotyping data gathered from 1,000 people with autism spectrum disorder (ASD) and 1,300 without ASD. The Autism Genome Project stated that those people with autism seemed to carry more submicroscopic insertions and deletions in their genome controls. Many of these appeared to be inherited, while others are considered to be new since they are found only in the affected children and not in the parents. This study was also able to recognize new genes that are susceptible including SHANK1, SYNGAP1, DLGAP2 and the X-linked DDX53-PTCHD1 locus. In other words, the identification of these genes could lead to the development of new treatment approaches (Anonymous, 2010).

Together, these results suggest that genes and parental age have a significant impact on the risks of having an autistic child. At the time there is no evidence to suggest preventions for these gene mutations. More research and longitudinal studies need to be performed so that someday scientists will understand the options to prevent these gene mutations from occurring. From there it may lead to proper treatment for this disorder. On the other hand, with the suggestion that reproduction age has an effect on the risks of autism, parents who fall into these categories could be screened to prevent the risks of having a child with autism.

References:Anonymous, (2010). New autism genes discovered. Business Wire. New York: June 9, 2010. Retrieved November 20, 2010 from ABI/INFORM Dateline (ProQuest) database.

Butcher, J., Mineka, S., Hooley, J., (2010). Abnormal psychology. Boston, MA: Allyn & Bacon.

King, M., Fountain, C., Dakhlallah, D., & Bearman, P. (2009). Estimated Autism Risk and Older Reproductive Age. American Journal of Public Health, 99(9), 1673-1679. Retrieved November 20, 2010 from Academic Search Elite database.

Lundstrom, S., Haworth, C., Carlstrom, E., Gillberg, C., Mill, J., Rastam, M., et al. (2010). Trajectories leading to autism spectrum disorders are affected by paternal age: findings from two nationally representative twin studies. Journal of Child Psychology & Psychiatry, 51(7), 850-856. doi:10.1111/j.1469-7610.2010.02223.x.

Saey, T. (2010). Some autism cases linked to rare mutations. Science News, 178(1), 12. Retrieved from Academic Search Elite database.

Seitler, B. (2010). New Information That People in High Places Do Not Want Us to Know About Autism. Ethical Human Psychology & Psychiatry, 12(2), 144-157. doi:10.1891/1559-4343.12.2.144.