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April 5th, 2012 
FAKE NEWS for the Zionist agenda WEDNESDAY, April 4 (HealthDay News) — Genetic mutations that
arise spontaneously, as opposed to being passed through generations, could
play an important role in the development of autism, new research
suggests.
Three research teams sequenced the genes of children with sporadic
autism, meaning it did not run in their families, and compared the
sequences with those of their parents and siblings. Their results were
published in three separate articles on April 4 in the journal
Nature.
“We found that 15 to 20 percent of sporadic patients could be explained
by ‘de novo’ [or spontaneous] mutations,” said Evan Eichler, professor of
genome sciences at the University of Washington in Seattle, who led one of
the studies.
Overall, the researchers identified hundreds of spontaneous mutations
in gene sequences that they predicted would upset the function of the
genes in the children with autism. Most of them were only found in single
patients.
The good news, according to Eichler, is that the multitude of affected
genes seems to belong to just a handful of pathways — involved in, for
example, development or cognition. That suggests that mutations in a
diverse set of genes could have a similar biological effect.
“This kind of investigation is of tremendous value for understanding
the genetic architecture of risk for autism,” said Andy Shih, vice
president of scientific affairs at Autism Speaks, a national advocacy
group.
“We can probably explain genetic risk factors that might lead to autism
in less than 30 percent of the population” from previous research, Shih
added.
Autism spectrum disorders, which include both mild and serious forms of
autism, affect one in 88 children in the United States, according to
just-updated statistics from the U.S. Centers for Disease Control and
Prevention.
The study led by Eichler involved 677 individuals representing 209
different families, each with one child who had sporadic autism. The
researchers found a total of 126 spontaneous mutations that they predicted
would have a severe effect on the genes in which they occurred.
Eichler’s team relied on samples from the Simons Simplex Collection, a
nationwide project that gathers blood and DNA from children with sporadic
autism and their unaffected family members.
A second study, led by researchers at Yale University in New Haven,
Conn., looked at 238 families from the Simons project, some of which
overlapped with Eichler’s study. They identified 125 de novo mutations
that would change the readout of genes among the children with autism and
87 among their unaffected siblings.
The third study in the trio found that just under half of children,
both with and without autism, had readout-altering spontaneous mutations,
but that the mutation rate was comparable between children with autism and
their unaffected siblings. This study was led by researchers at Harvard
Medical School, Massachusetts General Hospital in Boston and the Broad
Institute in Cambridge, Mass., and involved 175 sets of children with
autism and their parents.
Altogether, this body of research suggests that the frequency of de
novo mutations is not significantly higher in children with autism, but
that the types of mutations, which occur by chance, are more detrimental
in children with autism than those in their unaffected siblings, Eichler
said.
Eichler’s team also found that de novo mutations were four times as
likely to lie on DNA strands inherited from the father, and that the
number of mutations increases with paternal age.
The possible paternal influence suggests that many of the de novo
mutations originate in the father’s sex cells, which give rise to sperm.
Presumably, mutations would be more likely in paternal sex cells rather
than maternal ones because paternal cells continue to divide throughout a
man’s lifetime, giving them more chances to pick up mutations.
Although the link with paternal age agrees with some epidemiological
studies that have found higher rates of autism among children of older
parents, it probably only plays a part in a modest 10 percent or so of
patients, Eichler said.
From the three studies, mutations in two genes, called CHD8 and
KATNAL2, emerged as likely autism risk factors because they were found in
more than one patient. “Almost never did we see lightning strike the same
place twice,” Eichler said.
Unlike the myriad mutations identified in genes involved in neuronal
development, these mutations could have more universal effects on
regulating gene expression, cell growth and differentiation.
These two genes were also among the 49 genes that fell into the same
biological pathway, Eichler’s team found. “This one is a monster pathway,”
Eichler said, because it involves the largest number of identified de novo
mutations.
The gene mutations identified in this research “underscores that autism
is a complex interplay between genes and the environment,” Shih said. For
example, CHD8 can control the expression of other genes in response to
environmental stimuli.
This research is also a reminder that autism is a group of related
disorders involving many genes in different pathways, he added. “Each of
the genes [in these studies] seem to confer only a small risk, and are
only readily found in a small percentage of individuals with autism,” he
noted.
However, Shih said, these studies show that with more genetic analyses
involving more patients, “there could be some unifying principles revealed
that could allow identification of individuals at risk of autism and guide
therapeutics.”
More information
To learn more about autism, visit the Autism Society of
America.
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