| There
is no known single cause for autism, but it is generally accepted
that it is caused by abnormalities in brain structure or function.
Brain scans show differences in the shape and structure of the brain
in autistic versus non-autistic children. Researchers are investigating
a number of theories, including the link between heredity, genetics
and medical problems. In many families, there appears to be a pattern
of autism or related disabilities, further supporting a genetic
basis to the disorder. While no one gene has been identified as
causing autism, researchers are searching for irregular segments
of genetic code that autistic children may have inherited. It also
appears that some children are born with a susceptibility to autism,
but researchers have not yet identified a single "trigger"
that causes autism to develop.
Other
researchers are investigating the possibility that under certain
conditions, a cluster of unstable genes may interfere with brain
development resulting in autism. Still other researchers are investigating
problems during pregnancy or delivery as well as environmental
factors such as viral infections, metabolic imbalances, and exposure
to environmental chemicals.
Autism
tends to occur more frequently than expected among individuals
who have certain medical conditions, including Fragile X syndrome,
tuberous sclerosis, congenital rubella syndrome, and untreated
phenylketonuria (PKU). Some harmful substances ingested during
pregnancy also have been associated with an increased risk of
autism. Early in 2002, The Agency for Toxic Substances and Disease
Registry (ATSDR) prepared a literature review of hazardous chemical
exposures and autism and found no compelling evidence for an association;
however, there was very limited research and more needs to be
done.
The
question of a relationship between vaccines and autism continues
to be debated. In a 2001 investigation by the Institute of Medicine,
a committee concluded that the "evidence favors rejection
of a causal relationship.... between MMR vaccines and autistic
spectrum disorders (ASD)." The committee acknowledged, however,
that "they could not rule out" the possibility that
the MMR vaccine could contribute to ASD in a small number of children.
While other researchers agree the data does not support a link
between the MMR and autism, more research is clearly needed.
Whatever
the cause, it is clear that children with autism and PDD are born
with the disorder or born with the potential to develop it. It
is not caused by bad parenting. Autism is not a mental illness.
Children with autism are not unruly kids who choose not to behave.
Furthermore, no known psychological factors in the development
of the child have been shown to cause autism.
Disclaimer:ASF
DOES NOT ENDORSE ANY TREATMENT, MEDICATIONS, OR THERAPIES FOR
AUTISM. THE WRITTEN MATERIALS CONTAINED ON THIS SITE ARE FOR INFORMATIONAL
PURPOSES ONLY.
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