| New causal research findings lead to improved
strategies for early diagnosis, treatment and intervention. |
Autism was first recognized in 1942 by Dr. Leo Kanner, but in the
decades since, its causes are still far from understood. At one
time autism was mistakenly thought to be caused by "cold" parenting,
later it was wrongly classified as a childhood psychosis or a type
of childhood schizophrenia. Today research around the world focuses
on multiple possible causes of autism such as genetics/heredity,
differences in biological brain function (neuropathology), pre-natal
factors, possible exposure to environmental toxins, viral infections
and immune system deficiencies.
Research into Neurological Differences
| Autism Spectrum Disorder is not a mental
illness, there are no known psychological factors in the
development of the child that have been shown to cause autism.
ASD is not caused by bad parenting and children with ASDs are
not badly behaving kids. |
There is general acceptance that autism is caused by abnormalities
in brain structures or functions. People with ASDs have been shown
to have some structural and chemical differences in their brains
and other body systems. ASD occurs by itself or in association with
other conditions which affect the function of the brain such as
metabolic disturbances and epilepsy. It is known that autism interferes
with the usual intricate connections in the brain which control
and coordinate the areas of social interaction, sense perception
and communication.
- Researchers are investigating underlying brain differences in
autism through new methods of brain imaging.
- Studies are examining how the cerebellum develops and processes
information, how different brain regions function in relation
to each other, and how changes in this relationship during brain
development might result in the symptoms of autism. One theory
is that certain types of cells may migrate to places in the brain
where they are not meant to be.
- Possible biologic markers present at birth are also being studied
in order to identify infants at risk for the development of ASD.
- The specific aspects of behaviour, information processing and
other characteristics are also being studied in order to understand
better how children with autism differ from other people and how
these characteristics change over time.
Canadian Neurology Studies
Baby Sibs Study - A Study of Infant Siblings of Children with Autism Spectrum Disorders
Project led by NAAR and
NIH in the U.S., with Canadian partners: Dr. Lonnie Zwaigenbaum
at McMaster University and Dr. Susan Bryson at the IWK Health
Centre in Halifax. Researchers are examining infant siblings
of children with autism in the search for biological markers,
additional behavioural markers and developing early interventions
especially designed for infants and very young children.
(See full description of study)
Imaging Study – A Study of Serotonin Function in Parents with Autistic Children and in High Functioning Autistic Adults
CAIRN Study
(See full description of study) Autism Spectrum Disorders - Canadian-American Research Consortium (ASD-CARC)
ASD-CARC researchers are carrying out research aimed at understanding the neurobiology of ASDs and identifying early signs in infants at risk for developing an ASD.
(See study descriptions: Questionnaires to develop family profiles, and prospective identification of infants at risk for an ASD.) |
The Role of Genetics
There appears to be a pattern of ASD or related disabilities in
some families. Several studies involving twins indicate that autism
can be inherited. This suggests a genetic component to the disorder although,
at this time, no gene has been directly linked to autism. Some scientists
hope to identify irregular segments of genetic code that may increase
the risk of ASD although the genetic basis is believed to be highly
complex. Current evidence shows that 20 or more genes may be associated
with autism. This is in contrast to other disorders, such as Fragile
X or Rett's syndrome, in which single genes have been identified.
In addition, researchers are trying to understand whether some children
are born with more susceptibility to autism that may then be "triggered"
by certain factors.
If parents have a child with an ASD, there is a twenty-fold increased
likelihood that their next child will also develop symptoms of autism.
Sometimes cognitive disabilities go undetected in siblings of ASD
children. Siblings should be evaluated for possible developmental
delays and learning disabilities, such as dyslexia.
Canadian Research into Genetics
Autism Spectrum Disorders - Canadian-American Research Consortium (ASD-CARC)
ASD-CARC researchers are carrying out research aimed at identifying the genetic and environmental factors contributing to ASD susceptibility and identifying early signs in infants at risk for developing an ASD.
(See study descriptions: Questionnaires and laboratory methods to identify both genetic and environmental factors associated with ASDs, and prospective identification of infants at risk for an ASD.)
CAN-A-GEN and The Autism Genome Project
(See full Canadian study description)
CAN-A-GEN, which includes researchers from The Hospital for Sick Children in Toronto, is the Canadian arm of the worldwide Autism Genome Project, the largest study of autism genetics ever undertaken. This study is being funded by Autism Speaks in the U.S., as well as Genome Canada and the Canadian Institutes of Health Research (CIHR).
Simons Simplex Collection (SSC) Study
13 sites across the United States and Canada need your help to establish a permanent repository of genetic samples from 2000 families. Through rigorous phenotyping, we hope this search will lead to a better understanding of autism and to new effective therapies. For more information, contact Cara Schwartz, project coordinator at 514.412.4400 x23325 | Cara.Schwartz@muhc.mcgill.ca | More info available at https://sfari.org/simons-simplex-collection
Study Participants Needed |
Immune System
One theory of Autism Spectrum Disorder is that a child's immune
system may be compromised either genetically, through infection,
and/or environmentally (e.g. by exposure to chemicals). This may
make the child more susceptible. The brains and nervous systems
of some people with ASDs show signs of inflammation, suggesting
a link with immune response.
Birth Complications
Researchers are also investigating the potential for autism to develop during the pregnancy period. Any factor that disturbs normal brain development during pregnancy may have lifelong effects on the child's sensory, language, social and mental functioning. Researchers are looking at the effects of the mother's health and problems during delivery to discover any connections with brain development.
It is known that rubella (in utero) and strep (when very young) can cause autism in rare cases (referred to as PANDAS- Pediatric Autoimmune Neurological Disorder Associated with Strep).
Other Medical Conditions
People with medical conditions such as Fragile X syndrome, tuberous sclerosis, congenital rubella syndrome and untreated phenylketonuria (PKU) seem to have a higher risk for autism.
Exposure to Toxins
There are strongly varying opinions in the autism community
on a possible relationship between autism and exposure to mercury
in childhood vaccines. For years, most single dose vaccines
contained a preservative called thimerosal, which is 50% mercury.
The symptoms of mercury poisoning in children are very similar to
the symptoms of autism. Some studies suggested that the reported
incidence of autism began rising significantly when the Measles-Mumps-Rubella
(MMR) vaccine was introduced in the United States (1978) and in the United
Kingdom (1988). There is published research on both sides of
the thimerosal debate.
Other related areas of interest include the question of whether
maternal exposure to mercury may play a factor in autism, (e.g.
frequent eating of fish and seafood high in mercury, mercury dental
fillings, thimerosal in RhoGam shots). Pesticides and other environmental
toxins are also being considered. As yet, there is no general consensus
on which environmental factors, if any, might play a role.
Nutrition
Nutritional factors being investigated include a lack of essential
minerals such as calcium, zinc, magnesium, iodine, lithium and
potassium which may be important.
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