Three teams of scientists working independently to understand the biology of autism have for the first time homed in on several gene mutations that they agree sharply increase the chances that a child will develop the disorder, and have found further evidence that the risk increases with the age of the parents, particularly the father.
The gene mutations are extremely rare and together account for a tiny fraction of autism cases, suggesting that the search for therapies will be a long one, and that what is loosely known as autism may represent a broad category of related but biologically distinct conditions.
There are likely hundreds, perhaps thousands, of rare mutations that could disrupt brain development enough to result in social and developmental delays.
But experts said that the overlapping results, reported in three papers posted online Wednesday in the journal Nature, give scientists working on the genetics of autism something they have not had: a clear strategy for building a real understanding of the disease’s biological basis.
Researchers hope to find more similar, rare mutations in the next year or so that they estimate could account for 10 percent to 20 percent of all cases.
Biologists have been groping in vain for a reliable, verifiable foothold from which to investigate the underlying genetics of so-called autism spectrum disorders, including Asperger syndrome and related social difficulties that are being diagnosed at alarmingly high rates — on average, in one of 88 children, according to a government estimate released last week.
Previous studies have produced a scattering of gene findings but little consensus or confidence in how to proceed.
The new work provides a measure of both, as well as strong backing for earlier studies linking autism to the age of new fathers.
“These studies aren’t so much a breakthrough, because we knew this was coming,” said Jonathan Sebat, a geneticist at the University of California, San Diego, who was not a part of the research teams.
“But I’d say it’s a turning point. We now have a reliable way forward, and I think it’s fair to expect that we will find 20, 30, maybe more such mutations in the next year.”
Other researchers were more cautious, saying that the genetics of rare mutations was not yet well enough understood to make conclusive statements about their effect on the behavior of specific genes.
“This is a great beginning, and I’m impressed with the work, but we don’t know the cause of these rare mutations, or even their levels in the general population,” said Dr. Aravinda Chakravarti, of the Institute of Genetic Medicine at the Johns Hopkins University Medical School, who was not involved in the studies.
“I’m not saying it’s not worth it to follow up these findings, but I am saying it’s going to be a hard slog.”
The three research teams took a similar approach, analyzing genetic material taken from blood samples of families in which parents who have no signs of autism give birth to a child who develops the disorder.
This approach gives scientists the opportunity to spot the initial mutations that accompany the condition, rather than trying to work though possible genetic contributions from maternal and paternal lines.
In all three studies, the researchers focused on rare genetic glitches called de novo mutations.
De novo mutations are not inherited but occur spontaneously near or during conception. Most people have at least one and the overwhelming majority of them are harmless.
Read more here: Scientists Link Rare Gene Mutations to Heightened Risk of Autism - NYTimes.com
The gene mutations are extremely rare and together account for a tiny fraction of autism cases, suggesting that the search for therapies will be a long one, and that what is loosely known as autism may represent a broad category of related but biologically distinct conditions.
There are likely hundreds, perhaps thousands, of rare mutations that could disrupt brain development enough to result in social and developmental delays.
But experts said that the overlapping results, reported in three papers posted online Wednesday in the journal Nature, give scientists working on the genetics of autism something they have not had: a clear strategy for building a real understanding of the disease’s biological basis.
Researchers hope to find more similar, rare mutations in the next year or so that they estimate could account for 10 percent to 20 percent of all cases.
Biologists have been groping in vain for a reliable, verifiable foothold from which to investigate the underlying genetics of so-called autism spectrum disorders, including Asperger syndrome and related social difficulties that are being diagnosed at alarmingly high rates — on average, in one of 88 children, according to a government estimate released last week.
Previous studies have produced a scattering of gene findings but little consensus or confidence in how to proceed.
The new work provides a measure of both, as well as strong backing for earlier studies linking autism to the age of new fathers.
“These studies aren’t so much a breakthrough, because we knew this was coming,” said Jonathan Sebat, a geneticist at the University of California, San Diego, who was not a part of the research teams.
“But I’d say it’s a turning point. We now have a reliable way forward, and I think it’s fair to expect that we will find 20, 30, maybe more such mutations in the next year.”
Other researchers were more cautious, saying that the genetics of rare mutations was not yet well enough understood to make conclusive statements about their effect on the behavior of specific genes.
“This is a great beginning, and I’m impressed with the work, but we don’t know the cause of these rare mutations, or even their levels in the general population,” said Dr. Aravinda Chakravarti, of the Institute of Genetic Medicine at the Johns Hopkins University Medical School, who was not involved in the studies.
“I’m not saying it’s not worth it to follow up these findings, but I am saying it’s going to be a hard slog.”
The three research teams took a similar approach, analyzing genetic material taken from blood samples of families in which parents who have no signs of autism give birth to a child who develops the disorder.
This approach gives scientists the opportunity to spot the initial mutations that accompany the condition, rather than trying to work though possible genetic contributions from maternal and paternal lines.
In all three studies, the researchers focused on rare genetic glitches called de novo mutations.
De novo mutations are not inherited but occur spontaneously near or during conception. Most people have at least one and the overwhelming majority of them are harmless.
Read more here: Scientists Link Rare Gene Mutations to Heightened Risk of Autism - NYTimes.com
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