genetic mutations in the SHANK2 gene, partially responsible for linking nerve cells, and variants in the number of gene copies that were common to patients with autism and patients with mental retardation.
the same mutation can be present in an autistic patient with normal intelligence and in a mentally impaired patient
Our findings further link common genes between ASD and intellectual disability.
Mutations in 3 Genes Linked to Autism Spectrum Disorders : Mutations in three new genes have been linked to autism, according to new studies including one with investigators at Mount Sinai School of Medicine
The findings, in a trio of papers revealing new
genetic targets in autism, are published in the April 4th online issue
of the journal Nature.
The genes with
mutations identified in the studies – CHD8, SNC2A, and KATNAL2 – were
discovered with a new state-of-the-art genomics technology known as
exome sequencing, where all protein coding regions of the genome, called
the exome, are analyzed.
The researchers say that with further
characterization of the genes and sequencing of genes in thousands of
families, they will be able to develop novel therapeutics and preventive
strategies for autism.
The institutions involved in this study sequenced data from
more than 500 families (both parents and the affected child), examining
the protein-enriched areas of the genome.
“When the same
mutations are found in multiple affected children and none are found in
children without autism, we believe that we have identified mutations
that collectively affect a higher proportion of individuals with
autism,” said Dr. Buxbaum. “Our studies revealed that the proteins
encoded by the mutated genes interact with each other far more than
expected, demonstrating significantly greater connectivity than would be
expected.”
It found several genetic variants commonly associated with ASD, all of them pointing two specific genes found on chromosome 5 which control production of proteins which help cells stick to each other, and make nervous connections.
One variant, linked to a gene called CDH10, was so common - present in over 65% of cases of autism - that the researchers calculated that fixing it would cut the number of autism cases by 15%.
They also linked ASD rather less strongly to a group of about 30 genes which produce proteins that play a key role in enabling brain cells to migrate to correct places, and to connect to neighbouring cells.
Professor Simon Baron-Cohen, an autism expert at the University of Cambridge, said 133 genes had now been linked to the condition, and much work was needed to piece together how they interacted with each other and the environment.
The National Autistic Society said the exact causes of autism were unknown.
In a statement, the society said: "There is evidence to suggest that genetic factors are responsible for some forms of autism.
"However, the difficulty of establishing gene involvement is compounded by the interaction of genes and by their interaction with environmental factors.
"Various studies over many years have sought to identify candidate genes but so far inconclusively."
Advanced maternal age is linked to a significantly elevated risk of having a child with autism, regardless of the father's age, according to an exhaustive study of all births in California during the 1990s by UC Davis Health System researchers.
The researchers note that understanding the relationship between increased parental age and autism risk is critical to understanding its biological causes. Earlier studies have observed that advanced maternal age is a risk factor for a variety of other birth-related conditions, including infertility, early fetal loss, low birth-weight, chromosomal aberrations and congenital anomalies.
One possible clue comes from a 2008 UC Davis study that found some mothers of children with autism had antibodies to fetal brain protein, while none of the mothers of typical children did. Advancing age has been associated with an increase in autoantibody production.
They added that some persistent environmental chemicals accumulate in the body and also may have a role to play in autism, possibly contributing to the apparent effect of parental age.
The study also suggests that epigenetic changes over time "may enable an older parent to transfer a multitude of molecular functional alterations to a child ... thus epigenetics may be involved in the risks contributed by advancing parental age as a result of changes induced by stresses from environmental chemicals, co-morbidity or assistive reproductive therapy."
Advanced maternal age is linked to a significantly elevated risk of having a child with autism, regardless of the father's age, according to an exhaustive study of all births in California during the 1990s by UC Davis Health System researchers.
"Researchers from McGill University and the University of Montreal have identified a crucial link between protein synthesis and autism spectrum disorders (ASD), which can bolster new therapeutic avenues."
PubMed comprises more than 21 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.
PubMed comprises more than 21 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.
PubMed comprises more than 21 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.
PubMed comprises more than 21 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.
PubMed comprises more than 21 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.
PubMed comprises more than 21 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.
PubMed comprises more than 21 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.
[Functioning of memory in subjects with autism] [Encephale. 2008] - PubMed result
PubMed comprises more than 21 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.
PubMed comprises more than 21 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.
The only significant difference between AS and High Functioning Autism is that people with AS usually develop speech right on time while people with autism usually have speech delays.
3. People With Autism Are Different from One Another
4. There Are Dozens of Treatments for Autism - But No 'Cure'
5. There Are Many Theories on the Cause of Autism, But No Consensus
6. People Don't Grow Out of Autism
7. Families Coping with Autism Need Help and Support
8. There's No 'Best School' for a Child with Autism
Even in an ideal world, "including" a child with autism in a typical class may not be the best choice. Decisions about autistic education are generally made by a team made up of parents, teachers, administrators and therapists who know the child well.
9. There Are Many Unfounded Myths About Autism
Since every person with autism is different, however, such "always" and "never" statements simply don't hold water.
10. Autistic People Have Many Strengths and Abilities
They are also ideal candidates for many types of careers.
In recent years, Iacoboni has shown that mirror neurons may be an important element of social cognition and that defects in the mirror neuron system may underlie a variety of mental disorders, such as autism.
Mirror neurons are the only brain cells we know of that seem specialized to code the actions of other people and also our own actions. They are obviously essential brain cells for social interactions. Without them, we would likely be blind to the actions, intentions and emotions of other people.
The way mirror neurons likely let us understand others is by providing some kind of inner imitation of the actions of other people, which in turn leads us to “simulate” the intentions and emotions associated with those actions. When I see you smiling, my mirror neurons for smiling fire up, too, initiating a cascade of neural activity that evokes the feeling we typically associate with a smile.
In 2006 your lab published a paper in Nature Neuroscience linking a mirror neuron dysfunction to autism. How might reduced mirror neuron activity explain the symptoms of autism?
Reduced mirror neuron activity obviously weakens the ability of these patients to experience immediately and effortlessly what other people are experiencing, thus making social interactions particularly difficult for these patients. Patients with autism have also often motor problems and language problems. It turns out that a deficit in mirror neurons can in principle explain also these other major symptoms. The motor deficits in autism can be easily explained because mirror neurons are just special types of premotor neurons, brain cells essential for planning and selecting actions. It has been also hypothesized that mirror neurons may be important in language evolution and language acquisition.
Thus, a deficit in mirror neurons can in principle account for three major symptoms of autism, the social, motor and language problems.
There is convincing behavioral evidence linking media violence with imitative violence. Mirror neurons provide a plausible neurobiological mechanism that explains why being exposed to media violence leads to imitative violence.
I think there are two key points to keep in mind. The first one is the one we started with: mirror neurons are brain cells specialized for actions. They are obviously critical cells for social interactions but they can’t explain non-social cognition. The second point to keep in mind is that every brain cell and every neural system does not operate in a vacuum. Everything in the brain is interconnected, so that the activity of each cell reflects the dynamic interactions with other brain cells and other neural systems.
In recent years, Marco Iacoboni, a neuroscientist at the University of California at Los Angeles, has shown that mirror neurons may be an important element of social cognition and that defects in the mirror neuron system may underlie a variety of mental disorders, such as autism.
Autism street: For readers who may be interested in a skeptical perspective with regards to "mild" hyperbaric oxygen therapy for autism, I've assembled a short list of links.