Student guest post by Laura Vonnahme
The recent explosion in the rate of autism has prompted an increase in research as well as media hype. The disease, first described in 1943 by Leo Kenner, is a serious health condition that is now estimated to effect 1 in 110 children in the U.S. The nature of the disease and how to best treat it continues to puzzle researchers, as the symptoms and severity of the disease differ dramatically in all children diagnosed with the disorder. The disease manifests itself differently in all children and health care providers think of autism as a spectrum disorder, a group of disorders with similar features. One child may have mild symptoms, while another may have serious symptoms, but they both have an autism spectrum disorder. Currently the autism spectrum disorders (ASDs) include autistic disorder (classic autism), Asperger Syndrome and Pervasive Developmental Disorder Not Otherwise Specified (or atypical autism). Unlike, other diseases, ASDs are difficult to diagnose, as there is no specific medical test (1). Often doctors look at the child’s behavior and development to make a diagnosis.
Symptoms of ASDs can manifest differently and at different ages in children. Some children with an ASD show hints of ASD related problems within the first few months of life. In others, symptoms might not show up until 24 months or later. Some children with an ASD seem to develop normally until around 18-24 months of age and then they stop gaining new skills, or they lose the skills they once had. While early intervention services have shown to greatly improve a child’s development, there is no cure for ASDs (2). Generally, treatment is directed at particular symptoms, such as speech therapy for language delays, but there is no overall therapy to treat an ASD as a disease. In addition, while symptoms can improve, ASDs are lifelong disorders, that need continuous therapeutic interventions (5). Therefore, the origins and possible cause of the disease have become an important topic, as an identified cause of the ASDs can lead to an effective treatment.
There have been several theories presented in recent decades as to the cause and risk factors of ASDs; however, none of the theories have been solidified with scientific research. The most prominent theory, and the one that most scientists agree on, is that genes are one of the risk factors that can make a person more likely to develop an ASD. This is demonstrated by the fact that children who have a sibling or parent with an ASD are at higher risk of also having an ASD (3).
An additional theory is that ASDs are a result of an environmental factor, such as an infection. While this is highly speculative, there have been some recent findings that suggested ASDs could be a result of a blood borne pathogen. In October 2009, researchers from the University of Nevada, the National Cancer Institute and The Cleveland Clinic announced they had isolated particles from a retrovirus, called XMRV, possibly associated with ASDs. Researchers tested blood samples from a small group of children with autism and found that 40% of them were positive for XMRV and more testing is underway. While the researchers say XMRV could be linked to ASDs, they also say it is not the only factor, as there are genetic defects that contribute to ASDs. According to the research, XMRV can lie dormant in people, until it is turned on or off by other factors, such as stress hormones, or in response to the presence of inflammatory cytokines (7).
While the paper published only initial findings relating XMRV to ASDs, the lead author added to the recent controversy concerning the association between the MMR vaccine and autism. In October, Dr. Judy A. Mikovits said, “This might even explain why vaccines would lead to autism in some children, because these viruses live and divide and grow in lymphocytes — the immune response cells, the B and the T cells. So when you give a vaccine, you send your B and T cells in your immune system into overdrive. That’s its job. Well, if you are harboring one virus, and you replicate it a whole bunch, you’ve now broken the balance between the immune response and the virus. So you have had the underlying virus, and then amplified it with that vaccine, and then set off the disease, such that your immune system could no longer control other infections, and created an immune deficiency” (6). This statement was made months before the Lancet retracted the infamous British gastroenterologist Andrew Wakefield’s paper, linking autism to the MMR vaccine, published in 1998. The paper was retracted after scrutiny and subsequent investigations by British regulators leading to charges that Dr. Wakefield falsified data and was paid by the parents of autistic children. In addition, there have been several studies since disproving Wakefield’s research, implying that MMR vaccines are not the cause of ASDs (4).
Questions concerning ASDs and their link to a viral infection remain, and further studies are needed to prove or disprove this new theory linking XMRV to ASDs. In addition, further research is needed to pin down the exact significance of the relationship between the infection and ASDs. For example, is the virus implicated in the cause of autism, or do children harbor the virus as a result of autism (6)? As research continues to move forward, the causes and risk factors of these prevalent ASDs remain a mystery. Thus, until a link can be made between ASDs and their cause, it is unlikely that an effective treatment will be found.
1. “Autism Research Network.” Autism Research Network. N.p., n.d. Web. 15 Feb. 2010.
2. “Autism Spectrum Disorders (ASDs).” NICHD – The Eunice Kennedy Shriver National Institute of Child Health and Human Development Official Home Page. N.p., n.d. Web. 6 Feb. 2010.
3. “Autism.” WebPediatrics.com. N.p., n.d. Web. 16 Feb. 2010.
4. Berman , Jessica. “Lancet Disavowal of Autism Vaccine Connection May Lead to More Immunizations | Health | English.” News | English. N.p., n.d. Web. 16 Feb. 2010.
5. “CDC – Autism Spectrum Disorder (ASDs) – NCBDDD.” Centers for Disease Control and Prevention. N.p., n.d. Web. 15 Feb. 2010.
6. Kirby, David. “Is Autism Associated with A Viral Infection?.” Breaking News and Opinion on The Huffington Post. N.p., n.d. Web. 16 Feb. 2010.
7. Mikovits, Judy and Vincent Lombardi. “Detection of an Infectious Retrovirus, XMRV, in Blood Cells of Patients with Chronic Fatigue Syndrome .” Science 326 (2009): 585-589. Science AAAS. Web. 15 Feb. 2010.