As so many of you already know, autism is a complex condition, and the search for the cause of autism has, in some ways, been equally complex. Everyone who’s turned on the TV or read a newspaper is probably aware of the long raging debate over the MMR vaccine, thimerosol and autism (something I won’t be covering here), but current research into the cause of autism covers many more possibilities. Here are some of the highlights in autism research so far in 2008.
Genetics
There have been several recent studies on the genetic basis of autism. Early this year, we learned about findings from the Autism Genome Project Consortium, which looked at the rate of chromosomal changes in people with autism spectrum disorders (ASD). Researchers found 13 regions of the genome which showed chromosomal changes in unrelated people with autism, including a region on chromosome 16 which was found in 1% of cases. These results have led researchers to suggest genetic analysis should be a routine part of the medical workup for people with ASDs.
At MIT, researchers have discovered a gene called Shank1, which is involved in the structure and function of the nerve cell connections in the brain, called synapses. Mice lacking Shank1 showed a high aptitude for spatial learning tasks, but impairment in long-term memory retention. Researchers feel this gene may play a role in the brains of autistic savants.
Maternal Antibodies
The research that I found most interesting came out of the M.I.N.D. Institute. Their data suggests that an interaction between maternal antibodies and the developing fetal brain could be responsible repetitive behaviors, known as stereotypies, in children with the regressive form of autism.
The study was inspired by UC Davis immunologist Judy Van de Water’s discovery that certain antibodies found in the blood of mothers of children with the regressive form of autism (the type frequently linked to vaccinations) reacted with fetal brain tissue. Following this lead, researchers exposed pregnant monkeys to human maternal IgG at the end of their first trimester. Results showed that the offspring of monkeys exposed to IgG from mothers of autistic children had problems with social interaction, and displayed a higher and more frequent rate of certain repetitive behaviors.
Leaky Gut Theory and Opioids
The “leaky gut” theory of autism contends that gluten (and/or casein) sensitivity causes inflammation in the small bowel, resulting in damage which allows opioid peptides from food to be absorbed into the blood, where travel to the brain and cause the symptoms of autism. This theory led to the idea that excluding gluten and casein from the diet could treat or cure autism by reducing the levels of circulating opioids.
A recent study which compared levels of urinary opioids in autisitic boys with age-matched controls found no connection between opioids in the urine and autism. Because no urine opioids were found in the boys with autism, and overall urine profiles of boys with and without autism were the same, this indicates that tests for urine opioid peptides aren’t useful for the diagnosis of autism, and have no function in quantifying treatment success in autistic children. It’s important to note that this study did not look at the effectiveness of dietary therapy for the treatment of autism. It is possible that although the theory behind the mechanism was incorrect, these diets could still play a role in autism treatment.
Kristie McNealy is a freelance medical writer who covers issues in women’s and children’s health. She is also the founder of NICU 101, a website for parents of preemies and NICU babies.
Related posts:
- Autism on the rise in CA – and not because we’re counting better
- Autism Reads: From the financial strains of autism to bad parenting as the cause
- Autism Reads: From preemies at risk to financial and emotional bankruptcy
- Autism touches everyone, by Mammaren
- BBC News – Study identifies ‘many more’ autism genes
Genevieve Hinson is a social media coordinator for Children's Hospital Central California. She's also a writer, wife and mom to two boys and a girl. The opinions she expresses here are her own, as is her obsession for coffee.
