Autism Genetics Vs Environment

Is autism genetic, environmental or both?

The evidence continues to provoke and confound. The consensus from a group of studies concluded in the past six months is "both". But it's not as simple as that. Let's break it apart.

There is the multiplex version of autism (parents have multiple children with autism) in which several genes  are affected. This is the inherited type of autism.

The simplex version (parents have a single child with autism) breaks down into three types (but stay tuned, this will explode into a multitude of types very soon). First there are some rare inheritable disorders such as Rhett's and Fragile-X. These make up 8% of the multiplex type. Next there is a genetic version which is typically caused by mutated genes from aging parents. This is not inherited, but is still genetic. This, too, accounts for only 8% of the simplex cases. What is left is a  whopping 80+% of cases are not related to genetics. We used to think that autism 90% was genetic. One researcher called this new finding, "humbling".

As we all learned in biology, the environment of the mother's womb is instrumental in a baby's development. Researchers are now looking at the second trimester of pregnancy as being the key time that disruptions in development may occur. And high on the list of what they are looking at is a disruption of RNA functionality. RNA decodes the DNA strands in the body. If RNA is not performing its jobs correctly, huge changes can occur in the development of the child.

And now we come back to the miracle "cures" achieved with food supplements, changes in diet, hyper-oxygenation, etc. Is there a problem in specific children with the specific RNA mechanisms that ultimately create the proteins needed for food digestion, toxin removal and oxygenation? What is it about these remedies that affects not just the gastric system (for example), but affects the child's ability to communicate and to interact socially?

We also come back to the question: "What is autism and what are it's causes?" Will we continue to define it as a collection of symptoms: lack of social interaction, delayed/disrupted communication skills, etc.? Or will we define it in medical terms by the mechanisms that cause it. Stay tuned!

NIMH. (2011, 6 28). Autism Spring. Retrieved 10 31, 2011, from National Institute of Mental Health: http://www.nimh.nih.gov/about/director/2011/autism-spring.shtml

Landfills and Autism

Driving back today from an errand, I passed a garbage hauler headed for the landfill 4 miles away. It reminded me that our landfill not only serves the S.E. Michigan area (including Detroit), but garbage from the city of Toronto is also hauled there. This arrangement has been in place for about 10 years. That's a big landfill.

It appears to me that the rate and severity of autism are higher in my area than in other areas where I've lived and worked. If so, is the proximity of this landfill a coincidence? It will be a while before epidemiologists are able to answer my question. But I did find one preliminary study addressing the topic. When I googled "autism" and "landfills," this article appeared first:
Autism Spectrum Disorders and Identified Toxic Land Fills: Co-Occurrence Across States, by Xue Ming, Michael Brimacombe, Joanne H. Malek, Nisha Jani and George C. Wagner in Environmental Health Insights 2008:2. It was dated Aug 20, 2008. In their words:

We hypothesize that ASD are associated with early and repeated exposures to any of a number of toxicants or mixtures of toxicants. It is the cumulative effects of these repeated exposures acting upon genetically susceptible individuals that lead to the phenotypes of ASD.

In a nutshell, the authors found that the occurrence of autism is higher near Superfund landfill sites than in areas without landfills. They go on to give results of a simple first look at the situation.

The residence of 495 ASD patients in New Jersey by zip code and the toxic landfill sites were plotted on a map of Northern New Jersey. The area of highest ASD cases coincides with the highest density of toxic landfill sites while the area with lowest ASD cases has the lowest density of toxic landfill sites. Furthermore, the number of toxic Superfund sites and autism rate across 49 of the 50 states shows a statistically significant correlation...

There is a superfund site within 20 miles of where I live (in addition to the big landfill down the road). It's quite a complex situation and I'm not sure that we want to wait for the epidemiologists. Last week, the health advocate, Dr. Weil (DrWeil.com), wrote:

Environmental toxins such as lead, mercury and dioxin are serious hazards to human health. Fortunately, there are ways to both minimize your exposure to and lower the quantity of toxins in your body ... Avoid living or working near hazardous sites such as reclaimed landfills or toxic waste dumps.

In my opinion future parents should truly think about where they work, what they do and where they live in order to decrease their likelihood for genetic mutation and the risk of autism in their children.

TED Video on Right/Left Brain

There is an amazing video by Jill Bolte Taylor, (http://www.ted.com/talks/view/id/229) a Harvard-trained and published neuroanatomist who teaches at the Indiana University School of Medicine in Bloomington, IN. Dr. Taylor witnessed and then recorded her experience of undergoing a stroke. As a brain scientist, she has incredible insight. She discusses the differences between the left and right brains.

Dr. Taylor describes the right brain's organization as a parallel processor ... that is, it has it's pulse on all the senses, but has no structure to make sense of the input it receives. For example, she talks about hearing "wah, wah-wah, wah-wah", rather than "Hi, my name is Joe". Another example, she had difficulty distinguishing numbers on paper. She couldn't discriminate figure/ground.

She described the left brain as a serial processor (a typical computer) that is able to analyze, organize and communicate. She says that the left brain has the sense of self (ego?) whereas the right brain is cosmic / in touch with energy. This is all very interesting, quite fantastic, and depending on your religion and training, may make a lot of sense. It did for me.

I wonder if autism doesn't have some sort of right/left brain connection .... I've seen a number of children without verbal skills who struggle with reality and appear to be content in their inner world of songs, touch, lights, and spinnng (right brain with left brain missing). And then there is true Asperger's Syndrome, which seems to be all left brain.

Dr. Taylor has a book, "My Stroke of Insight", that covers this same ground in depth.

Sensory Profile Factors

Article

Ermer, J. & Dunn, W. (1998). The sensory profile: a discriminant analysis of children with and without disabilities. American Journal of Occupational Therapy, 52, 283-290.

Here is an older study done in Kansas that looks at the factors (1-9) in the Sensory Profile for positive correlations to autism and ADHD. (The authors note that this process can be done for other disabilities, as well. I vote for Fetal Alcohol Syndrome!)

ADHD can be distinguished by high scores in Factors 1 and 5, sensory seeking and inattention/distractibilty and low scores in factors 4 and 9, oral sensitivity and fine motor perceptual.

Autism can be distinguished by high scores in Factors 4, 5 and 9, sensory seeking, inattention/distractibilty and oral sensitivity and low scores in factor 4, fine motor perceptual.

The study results had a statistical error, the assumption of homogeneity of variance was violated for the control group, and so these results must be used conservatively.

Questions for research:
1. Will these results pass muster on a larger population?
2. What does the factor profile look like for FAS, ODD, CD, etc.?

Parameters of Modulation

I recently read the March/April, 2007, Sensory Integration issue of AJOT. Lots of great articles. I was especially interested in the lead in article that describes the push for three SI diagnosies in the DSM. They are Sensory Modulation Disorder, Sensory-Based Motor Disorder and Sensory Discriminiation Disorder. With this breakdown (and some sub-categories underneath them) we come closer to being able to perform meaningful research in the area of modulation. Although we have diagnostic and therapeutic tools for motor and discrimination, these are not in place for modulation.

For example, we have developmental scales and excellent assessments for a child's motor skills. They are quite specific, and provide a therapist working with a child with motor delays with a measure of the disability as well as indicate an enumerated set of goals to reach.

Similar OT-based tools for modulation will tell us what modulation behaviors are typical for children at various ages. This in turn will allow us to create assessment tools for children with sensory disorders (including autism) and will allow us to estimate the degree of problem a child has, as well as where they are on the developmental scale. Good assessments will give us milestones for our treatment, and allow us to determine if indeed our treatment is effective. On a larger scale, these tools will allow us to perform quantitative research interventions on large populations. (This topic is also addressed in depth in other articles within the same issue of AJOT).

We need to know precisely the qualities of modulation and their developmentaly characteristics. According to Williamson and Anzalone, the qualities of modulation for infants and toddlers include arousal, attention, affect, and attention. Can we quantify these, assess them in clinical (and other) contexts? For example, can we talk about joint attention, object manipulation, object play, etc.? I am guessing that there are many subtleties here. I hope that we can find specific assessable qualities that are general enough to give us a picture of the child (as the motor assessments do). A resource I have not yet looked at is the zero-to-three foundation's publications (with the exception of the book cited below).

Sources:
1. Miller, L.J., Anzolone, M. E., Lane, S. J., Cermak, S. A., & Olsten, E. T. (2007). Concept evolution in sensory integration: A proposed nosology for diagnosis. American Journal of Occupational Therapy, 61, 135-140.

2. Williamson, G. G., & Anzalone, M. E. (2001). Sensory integration and self regulation in infants and toddlers: helping very young children interact with their environment. ZERO-TO-THREE: National Center for Infants, Toddlers and Families.