Autism is on the rise, is mainly not due to better diagnosis and cannot be genetic
is on the rise
recent Cambridge University report says that autism rates are as high as 1 in
60 in UK. http://www.dailymail.co.uk/news/article-1163606/One-child-60-suffers-form-autism.html.
show it is not due to better diagnosis
UC Mind Institute recently released a study that shows most of the increased
rates of autism are real, cannot be directly genetic and therefore due to
environmental factors (toxins and infections) and that better diagnosis is just
a small part of the statistics. http://www.medicalnewstoday.com/articles/134717.php
autism was due to better diagnosis you would see an equal decrease in mental
retardation which may now qualify for an autism spectrum diagnosis today.
If this were the case the IDEA and CDC chart data below, overall, would be
flat. The increase of autism and autism spectrum disorder (developmental
delay) was at least double the decrease in mental retardation which cause the
overall numbers to continue to climb.
The fastest growing genetic disorder
is a 1% increase over a 100-year period. If you ask any person working
with children (i.e. school teacher) if they have seen more than a ¼% increase
of autism in the last 25 years (regardless of how you would diagnose it) you’ll
hear “yes” virtually every time. Autism is triggered by elements other
than genes (it must be environmental).
Genetics And Autism
11-15% of autism cases have been shown to have ANY relationship to genetics.
is no evidence of a direct genetic link to autism.
of the genetic variants found were only susceptibilities, meaning you
could have the genetic profile and not have autism.
UC Mind Institute Study Says Much of the Increase is
Medical News Today
UC Davis M.I.N.D. Institute Study
Shows California's Autism Increase Not Due To Better Counting, Diagnosis
08 Jan 2009
A study by researchers at the UC
Davis M.I.N.D. Institute has found that the seven- to eight-fold increase in
the number children born in California with autism since 1990 cannot be
explained by either changes in how the condition is diagnosed or counted - and
the trend shows no sign of abating.
Published in the January 2009
issue of the journal Epidemiology, results from the study also suggest that
research should shift from genetics to the host of chemicals and infectious
microbes in the environment that are likely at the root of changes in the
neurodevelopment of California's children.
"It's time to start looking
for the environmental culprits responsible for the remarkable increase in the
rate of autism in California," said UC Davis M.I.N.D. Institute researcher
Irva Hertz-Picciotto, a professor of environmental and occupational health and
epidemiology and an internationally respected autism researcher.
Hertz-Picciotto said that many
researchers, state officials and advocacy organizations have viewed the rise in
autism's incidence in California with skepticism.
The incidence of autism by age six
in California has increased from fewer than nine in 10,000 for children born in
1990 to more than 44 in 10,000 for children born in 2000. Some have argued that
this change could have been due to migration into California of families with
autistic children, inclusion of children with milder forms of autism in the
counting and earlier ages of diagnosis as consequences of improved surveillance
or greater awareness.
Hertz-Picciotto and her co-author,
Lora Delwiche of the UC Davis Department of Public Health Sciences, initiated
the study to address these beliefs, analyzing data collected by the state of
California Department of Developmental Services (DDS) from 1990 to 2006, as
well as the United States Census Bureau and state of California Department of
Public Health Office of Vital Records, which compiles and maintains birth
Hertz-Picciotto and Delwiche
correlated the number of cases of autism reported between 1990 and 2006 with
birth records and excluded children not born in California. They used Census
Bureau data to calculate the rate of incidence in the population over time and
examined the age at diagnosis of all children ages two to 10 years old.
The methodology eliminated
migration as a potential cause of the increase in the number of autism cases.
It also revealed that no more than 56 percent of the estimated 600-to-700
percent increase, that is, less than one-tenth of the increased number of
reported autism cases, could be attributed to the inclusion of milder cases of
autism. Only 24 percent of the increase could be attributed to earlier age at
"These are fairly small
percentages compared to the size of the increase that we've seen in the
state," Hertz-Picciotto said.
Hertz-Picciotto said that the
study is a clarion call to researchers and policy makers who have focused
attention and money on understanding the genetic components of autism. She said
that the rise in cases of autism in California cannot be attributed to the
state's increasingly diverse population because the disorder affects ethnic
groups at fairly similar rates.
"Right now, about 10 to 20
times more research dollars are spent on studies of the genetic causes of
autism than on environmental ones. We need to even out the funding,"
The study results are also a
harbinger of things to come for public-health officials, who should prepare to
offer services to the increasing number of children diagnosed with autism in
the last decade who are now entering their late teen years, Hertz-Picciotto
"These children are now moving
toward adulthood, and a sizeable percentage of them have not developed the life
skills that would allow them to live independently," she said.
The question for the state of
California, Hertz-Picciotto said, will become: 'What happens to them when their
parents cannot take care of them?'
"These questions are not
going to go away and they are only going to loom larger in the future. Until we
know the causes and can eliminate them, we as a society need to provide those
treatments and interventions that do seem to help these children adapt. We as
scientists need to improve available therapies and create new ones,"
Hertz-Picciotto and her colleagues
at the M.I.N.D Institute are currently conducting two large studies aimed at
discovering the causes of autism. Hertz-Picciotto is the principal investigator
on the CHARGE (Childhood Autism Risk from Genetics and the Environment) and
MARBLES (Markers of Autism Risk in Babies-Learning Early Signs) studies.
CHARGE is the largest epidemiologic
study of reliably confirmed cases of autism to date, and the first major
investigation of environmental factors and gene-environment interactions in the
disorder. MARBLES is a prospective investigation that follows women who already
have had one child with autism, beginning early in or even before a subsequent
pregnancy, to search for early markers that predict autism in the younger
"We're looking at the
possible effects of metals, pesticides and infectious agents on
neurodevelopment," Hertz-Picciotto said. "If we're going to stop the
rise in autism in California, we need to keep these studies going and expand
them to the extent possible."
The study was funded by grants
from the National Institute of Environmental Health Sciences (NIEHS) and by the
In 1998, dedicated families
concerned about autism helped found the UC Davis M.I.N.D. (Medical
Investigation of Neurodevelopmental Disorders) Institute. Their vision? Experts
from every discipline related to the brain working together toward a common
goal: curing neurodevelopmental disorders. Since that time, collaborative
research teams at the M.I.N.D. Institute have turned that initial inspiration
into significant contributions to the science of autism, fragile X syndrome,
Tourette's syndrome, learning disabilities and other neurodevelopmental
disorders that can limit a child's lifelong potential.
UC Davis M.I.N.D.
Main News Category: Autism
NY Times: Genes Show
Limited Value in Predicting Diseases
By NICHOLAS WADE
April 16. 2009
The era of personal genomic medicine may have to wait. The
genetic analysis of common disease is turning out to be a lot more complex than
Since the human genome was decoded in 2003, researchers have
been developing a powerful method for comparing the genomes of patients and
healthy people, with the hope of pinpointing the DNA changes responsible for
This method, called a genomewide association study, has
proved technically successful despite many skeptics’ initial doubts. But it has
been disappointing in that the kind of genetic variation it detects has turned
out to explain surprisingly little of the genetic links to most diseases.
A set of commentaries in this week’s issue of The New
England Journal of Medicine appears to be the first public attempt by
scientists to make sense of this puzzling result.
One issue of debate among researchers is whether, despite
the prospect of diminishing returns, to continue with the genomewide studies,
which cost many millions of dollars apiece, or switch to a new approach like
decoding the entire genomes of individual patients.
The unexpected impasse also affects companies that offer
personal genomic information and that had assumed they could inform customers
of their genetic risk for common diseases, based on researchers’ discoveries.
These companies are probably not performing any useful
service at present, said David B. Goldstein, a Duke University geneticist who
wrote one of the commentaries appearing in the journal.
“With only a few exceptions, what the genomics companies are
doing right now is recreational genomics,” Dr. Goldstein said in an interview.
“The information has little or in many cases no clinical relevance.”
Unlike the rare diseases caused by a change affecting only
one gene, common diseases like cancer and diabetes are caused by a set of
several genetic variations in each person. Since these common diseases
generally strike later in life, after people have had children, the theory has
been that natural selection is powerless to weed them out.
The problem addressed in the commentaries is that these
diseases were expected to be promoted by genetic variations that are common in
the population. More than 100 genomewide association studies, often involving
thousands of patients in several countries, have now been completed for many
diseases, and some common variants have been found. But in almost all cases
they carry only a modest risk for the disease. Most of the genetic link to
disease remains unexplained.
Dr. Goldstein argues that the genetic burden of common diseases
must be mostly carried by large numbers of rare variants. In this theory,
schizophrenia, say, would be caused by combinations of 1,000 rare genetic
variants, not of 10 common genetic variants.
This would be bleak news for those who argue that the common
variants detected so far, even if they explain only a small percentage of the
risk, will nonetheless identify the biological pathways through which a disease
emerges, and hence point to drugs that may correct the errant pathways. If
hundreds of rare variants are involved in a disease, they may implicate too
much of the body’s biochemistry to be useful.
“In pointing at everything,” Dr. Goldstein writes in the
journal, “genetics would point at nothing.”
Two other geneticists, Peter Kraft and David J. Hunter of
the Harvard School of Public Health, also writing in the journal, largely agree
with Dr. Goldstein in concluding that probably many genetic variants, rather
than few, “are responsible for the majority of the inherited risk of each
But they disagree with his belief that there will be
diminishing returns from more genomewide association studies.
“There will be more common variants to find,” Dr. Hunter
said. “It would be unfortunate if we gave up now.”
Dr. Goldstein, however, said it was “beyond the grasp of the
genomewide association studies” to find rare variants with small effects, even
by recruiting enormous numbers of patients. He said resources should be
switched away from these highly expensive studies, which in his view have now
done their job.
“If you ask what is the fastest way for us to make progress
in genetics that is clinically helpful,” he said, “I am absolutely certain it
is to marshal our resources to interrogate full genomes, not in fine-tuning our
analyses of common variations.”
He advocates decoding the full DNA of carefully selected
Dr. Kraft and Dr. Hunter say that a person’s genetic risk of
common diseases can be estimated only roughly at present but that estimates
will improve as more variants are found. But that means any risk estimate
offered by personal genomics companies today is unstable, Dr. Kraft said, and
subject to upward or downward revision in the future.
Further, people who obtain a genomic risk profile are likely
to focus with horror on the disease for which they are told they are at highest
risk. Yet this is almost certain to be an overestimate, Dr. Kraft said.
The reason is that the many risk estimates derived from a
person’s genomic data will include some that are too high and some that are too
low. So any estimate of high risk is likely to be too high. The phenomenon is
called the “winner’s curse,” by analogy to auctions in which the true value of
an item is probably the average of all bids; the winner by definition has bid
higher than that, and so has overpaid.
Dr. Kari Stefansson, chief executive of deCODE Genetics, an
Icelandic gene-hunting company that also offers a personal genome testing
service, said deCODE alerted clients to pay attention to diseases for which
testing shows their risk is three times as great as average, not to trivial
increases in risk.
Dr. Stefansson said his company had discovered 60 percent of
the disease variants known so far.
“We have beaten them in every aspect of the game,” he said
of rival gene hunters at American and British universities.
The undiscovered share of genetic risk for common diseases,
he said, probably lies not with rare variants, as suggested by Dr. Goldstein,
but in unexpected biological mechanisms. DeCODE has found, for instance, that
the same genetic variant carries risks that differ depending on whether it is
inherited from the mother or the father.