Autistic Disorder and Intellectual Disability: 70% Is Not a Coincidence, It Is a Vast Majority

                                  

The DSM-IV and popular media interpretation of the autism disorders (pervasive developmental disorders), have encouraged the world to see autism as shy or introverted personality and a different, sometimes superior, way of thinking and has obscured the very obvious and close connection between autistic disorder, the most severe form of autism, and intellectual disabilities.

Autism is described in a CHARGE Study article as follows (emphasis added, HLD):

"Autism is a serious neurodevelopmental disorder characterized by impairments in social interaction, abnormalities in verbal and nonverbal communication, and restricted, stereotyped interests and behaviors (American Psychiatric Association 1994). Although a large proportion of individuals with autism manifest abnormal development from birth, a subset of at least 20–30% experience a regression with onset between 18 and 24 months of age after a period of apparently normal development (Lainhart et al. 2002). Autistic disorder is the most severe form of autism spectrum disorders (ASDs), which include Asperger’s syndrome and pervasive developmental disorders (PDDs) not otherwise specified. Approximately 70% of individuals with autistic disorder have some degree of mental retardation, and about half are nonverbal or have very impaired speech.

The CHARGE Study: An Epidemiologic Investigation of Genetic and Environmental Factors Contributing to Autism, Irva Hertz-Picciotto et al.

CDC autism expert Dr. Marshalyn Yeargin-Allsopp has described those with intellectual disability as the "vast majority" of the original,  pre DSM-IV autism:

"But the autism umbrella has since widened to include milder forms, says Dr. Marshalyn Yeargin-Allsopp, a medical epidemiologist at the CDC. For example, it now includes Asperger syndrome, where the sufferer is socially impaired, but experiences typical language development.

Another difference between past and present autism diagnosis involves the presence of intellectual disabilities, adds Yeargin-Allsopp. During the 1960s and 1970s, the vast majority of those diagnosed with autism had an intellectual disability but today, only about 40% have one."

CDC Autism Expert Dr. Marshalyn Yeargin-Allsopp 

The attempt to hide the very strong and clear relationship between autistic disorder and intellectual disability is more than just wrong it is the last politically correct form of discrimination ... discrimination against those with intellectual disabilities.  It is also a huge step backwards in understanding the truth about autism, that autism is a form of intellectual disability, most evident in those with autistic disorder.  Studies of high functioning persons with autism and Asperger's are routinely reported as representing all persons with autism disorders even those with intellectual disability who are intentionally excluded from the studies.  

Autism Speaks & CDC Autism Prevalence Increase Workshop Timely: Autism is Rising & Environmental Factors Likely Involved

"Based on the above mentioned research, approximately 53% percent of the increase in autism prevalence over time may be explained by changes in diagnosis (26%), greater awareness (16%), and an increase in parental age (11%). While this research is beginning to help us understand the increase in autism prevalence, half of the increase is still unexplained and not due to better diagnosis, greater awareness, and social factors alone. Environmental factors, and their interactions with genetic susceptibilities, are likely contributors to increase in prevalence and are the subject of numerous research projects currently supported by Autism Speaks.

The increase in autism prevalence is real and the public health crisis is growing. More families are affected by autism today then ever before."

Autism Speaks Official Blog, October 22, 2010

The above statement by Autism Speaks was based on several published sources and CDC information. including articles by authors Bearman and King, who have indicated that approximately 50% (47%) of autism prevalence increases are based on factors other than social factors. Now Autism Speaks and the Centers for Disease Control and Prevention (CDC) are co-sponsoring a workshop  on February 1, 2011 to investigate the changes in autism prevalence over time in the United State:

"The purpose of this workshop is to identify promising directions, priorities, and needs for better understanding ASD prevalence trends. The workshop will include presentations on what has been done to understand reasons for ASD prevalence changes, examples of understanding prevalence change from other conditions, and panel breakout sessions to allow for further discussions.


This meeting is open to the public with pre-registration required by January 24, 2011 for US citizens and January 13 for non-US citizens."

Autism Speaks Official Blog, January 5, 2011

While Autism Speaks has been puzzling at times in its efforts to "speak" about autism disorders, promoting the careers of purported autism spokespersons who question the very existence of autism as a  medical  disorder,  the importance of the above initiative can not be overstated.  For far too long the "it's gotta be genetic" mindset has held sway and prevented substantial scientific exploration of possible environmental causes or triggers of autism. Hopefully the recent US Senate hearings, official statements by the IACC acknowledging the emergence of a gene environment interaction paradigm, the CHARGE study, work by Dr. Irva Hertz-Picciotto and UN Davis M.I.N.D. researchers,  and efforts like the Autism Speaks/CDC prevalence workshop will lead to further environmental autism research; research which should have been commenced  years ago.

In 2010 the Gene Environment Interaction Model of Autism CHARGEd to the Fore

"Uncovering environmental causes of autism

CHARGE (Childhood Autism Risks from Genetics and the Environment) was launched in 2003 as a study of 1,000 to 2,000 children with differing patterns of development. The goal is to better understand the causes and contributing factors for autism or developmental delay. Three groups of children are being enrolled in the CHARGE study: children with autism, children with developmental delay who do not have autism and children from the general population. All of them are evaluated for a broad array of exposures and susceptibilities.

Refining our understanding of environment-gene interactions

Little is known about what causes autism or developmental delay. We will learn how genes and the environment interact to change children’s behaviors and skills. By studying a large number of children, we will discover which particular genes and/or environmental exposures might result in non-typical patterns of development and special subtypes of autism or developmental delay."

2010 could be known as the year that serious autism research arising from the genetic-environmental interaction model CHARGE'd to the fore with two major genetic-environmental focused autism research studies being published and receiving widespread attention.   2010 could also come to be known as  the year that  the "it's gotta be genetic" model of autism causation began its retreat from the battlefield in our attempt to understand autism causes  and seek autism cures.  Nothing can be done to retroactively counter the  time, financial resources,  attention and energies lost promoting the ill conceived notion that all autism disorders are 100% genetically based but there are now clear signs we are moving forward in our efforts to understand what causes autism disorders and real progress is being made.

Researchers involved with the recent mitochondrial dysfunction study and the proximity to proximity to highways (and air borne pollutants) study used data from the CHARGE program.  In each case the study authors are careful to report the limitations of their studies and to indicate that their studies indicate associations but do not, as yet,  identify specific causes of autism disorders. The studies  are exploratory and provide the foundation for further research.  Such studies are long overdue and are very welcome. 

A solid foundation for serious autism research has been established.  The autism research paradigm shift whispered about over  the last 3 years is now fully emerging and we are seriously studying the interaction of genetic and environmental research.  The gene environment model of autism is strongest in  California where researchers like  Dr. Irva Hertz-Picciotto, principal investigator on the CHARGE study, Dr.  Heather E. Volk  and Dr. Cecelia Giulvi use data from the CHARGE program as the basis for their research. 

The gene environment model of autism was also featured prominently at the  US Senate Committee on Environment and Public Works, Subcommittee on Children’s Health hearing entitled, "State of Research on Potential Environmental Health Factors with Autism and Related Neurodevelopment Disorders"   in August 2010. One of those who made written submission to the hearing was Dr. Isaac N. Pessah, Director UC Davis Center for Children’s Environmental Health and Disease Prevention Professor of Toxicology and a Co-Investigator with the CHARGE study.

There are signs Canada has also  begun to embrace the gene environment model of autism causation.  The York Alliance Autism Research Group includes  Dr. Dorothy Crawford,  focusing on gene environment interaction as causes of autism disorders in her research. Even the US IACC (Interagency Autism Coordinating Committee) has acknowledged, albeit somewhat timidly, the emergence of the gene environment model in understanding autism causation:

"As with many complex disorders, causation is generally thought to involve some forms of genetic risk interacting with some forms of non-genetic environmental exposure. ... In addition, a number of other environmental factors are being explored through research because they are known or suspected to influence early development of the brain and nervous system. Recent studies suggest factors such as parental age, exposure to infections, toxins, and other biological agents may confer environmental risk. ... Progress in identifying environmental factors which increase autism risk has been made recently (Eskenazi et al., 2007; Palmer et al., 2006; Palmer, Blanchard,; Wood, 2009; Rauh et al., 2006; Roberts et al., 2007; Windham et al., 2006), although this area of research has received less scientific attention and far fewer research dollars than genetic risk factors"

I have bold highlighted the last quoted statement from the IACC because it confirms exactly what has been said about autism research funding by autism researches from Dr. Teresa Binstock to Dr. Irva Hertz-Picciotto. Funding dollars have gone overwhelmingly toward genetic based autism research at the expense of environment autism research and that imbalance must be corrected.  Hopefully, as the gene environment model continues to gain ground amongst scientists involved in autism research that imbalance will also be corrected by funding authorities from government agencies to Autism Speaks.

It is time to CHARGE ahead with the gene environment interaction model of understanding and researching autism disorders.