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Tero Toivanen

Research on the genomics of autism from the Center for Biom - 0 views

www.theautismnewswire.com/NewsITems.aspx

research autism genomics genes DNA gene alterations brain development nerve signaling

shared by Tero Toivanen on 19 Mar 11 - No Cached
  • Research on the genomics of autism from the Center for Biomedical Informatics at The Childrens Hospital of Philadelphia indicated that several genes and genomic variants contribute to autism. The gene alterations are rare but when they are in play, they seem to disrupt genes that are significantly involved in brain development and nerve signaling.
  • According to the September 15, 2010 issue of Science Translational Medicine, males with certain DNA alterations to their X-chromosome are at high risk of having autism.
  • This research was performed at the Centre for Addiction and Mental Health (CAMH) and The Hospital for Sick Children (SickKids), in Toronto Canada.
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  • One percent of boys with autism involved in the study had mutations in the PTCHD1 gene on the X-chromosome. No boys without autism showed this mutation.
  • Girls who also had this mutation did not seem to exhibit autistic traits. It appears that girls may be protected from developing autism because they have a second X-chromosome.
  • Still these girls could be carriers, passing on the mutation to their children. Their sons could then have autism.
  • Certain rare genetic variants were found 20 percent more in children with autism than in other children. Researchers also discovered new disruptions, where a child of non-autistic parents had autism.
  • t appears that some children have private genetic mutations not passed on genetically, and this leaves them more susceptible to autism. Interestingly, each child showed a different disturbance in a different gene.
  • Researchers hope to gain more information as they identify groups of disrupted genes. Ultimately they hope to be able to develop treatments for autism.
Tero Toivanen

A week ago, a new study published in the Archives of General - 0 views

www.theautismnewswire.com/NewsITems.aspx

study autism research gene mutation ASD sporadic spectrum disorders de novo spontaneous mutations intellectual disability epilepsy

shared by Tero Toivanen on 22 May 11 - No Cached
  • The Howard Hughes Medical Institute describes how researchers using "high-throughput gene sequencing technology" were able to identify several de novo or spontaneous gene mutations in 20 children with sporadic autism spectrum disorders -- that is, their family members showed no other sign of autism.
  • The team identified 21 spontaneous mutations -- meaning they weren't inherited from either parent -- in the children's DNA. Eleven of these were mutations that would alter the protein encoded by the affected gene. In four of the 20 children, the researchers found mutations that were severe, some of which have been previously linked to autism, intellectual disability, and epilepsy.
  • one child had a mutation in the GRIN2B gene, which is crucial for neuronal signaling.
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  • Another individual had an extra nucleotide in FOXP1, a gene that, along with its close relatives, has been heavily implicated in language defects.
  • These new findings support the 'multi-hit' model of autism, which suggests that having more than one mutation can cause or worsen symptoms of autism and other brain disorders. The different combinations of mutations may contribute to the heterogeneity in ASDs.
  • That such different combinations of genetic mutations contribute to a child being autistic could account for why individuals with an ASD diagnosis have some very similar, and very different, features.
  • Tero Toivanen on 22 May 11
     
    "The Howard Hughes Medical Institute describes how researchers using "high-throughput gene sequencing technology" were able to identify several de novo or spontaneous gene mutations in 20 children with sporadic autism spectrum disorders -- that is, their family members showed no other sign of autism."
Tero Toivanen

Autism disorders might be reversible. | - I Teach Autism.com - - 0 views

www.iteachautism.com/...-or-disorder-may-be-reversible

autism fever epigenetics locus coeruleus brain neurobiology LC-NA system theory Albert Einstein College

shared by Tero Toivanen on 08 Jun 09 - Cached
  • Scientists at Albert Einstein College of Medicine of Yeshiva University have proposed a sweeping new theory of autism that suggests that the brains of people with autism are structurally normal but dysregulated, meaning symptoms of the disorder might be reversible.
  • The central tenet of the theory, published in the March issue of Brain Research Reviews, is that autism is a developmental disorder caused by impaired regulation of the locus coeruleus, a bundle of neurons in the brain stem that processes sensory signals from all areas of the body.
  • The new theory stems from decades of anecdotal observations that some autistic children seem to improve when they have a fever, only to regress when the fever ebbs.
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  • Einstein researchers contend that scientific evidence directly points to the locus coeruleus–noradrenergic (LC-NA) system as being involved in autism. “The LC-NA system is the only brain system involved both in producing fever and controlling behavior,” says co-author Dominick P. Purpura, M.D., dean emeritus and distinguished professor of neuroscience at Einstein.
  • The locus coeruleus has widespread connections to brain regions that process sensory information.
  • It is also involved in a variety of complex behaviors, such as attentional focusing (the ability to concentrate attention on environmental cues relevant to the task in hand, or to switch attention from one task to another).
  • “What is unique about the locus coeruleus is that it activates almost all higher-order brain centers that are involved in complex cognitive tasks,” says Dr. Mehler.
  • Drs. Purpura and Mehler hypothesize that in autism, the LC-NA system is dysregulated by the interplay of environment, genetic, and epigenetic factors (chemical substances both within as well as outside the genome that regulate the expression of genes). They believe that stress plays a central role in dysregulation of the LC-NA system, especially in the latter stages of prenatal development when the fetal brain is particularly vulnerable.
  • Drs. Purpura and Mehler believe that, in autistic children, fever stimulates the LC-NA system, temporarily restoring its normal regulatory function.
  • the future of autism treatment probably lies in drugs that selectively target certain types of noradrenergic brain receptors or, more likely, in epigenetic therapies targeting genes of the LC-NA system.
  • “You can’t take a complex neuropsychiatric disease that has escaped our understanding for 50 years and in one fell swoop have a therapy that is going to reverse it — that’s folly. On the other hand, we now have clues to the neurobiology, the genetics, and the epigenetics of autism. To move forward, we need to invest more money in basic science to look at the genome and the epigenome in a more focused way.”
  • Tero Toivanen on 08 Jun 09
     
    Scientists at Albert Einstein College of Medicine of Yeshiva University have proposed a sweeping new theory of autism that suggests that the brains of people with autism are structurally normal but dysregulated, meaning symptoms of the disorder might be reversible.
Tero Toivanen

Asperger Syndrome Tied to Low Cortisol Levels - 0 views

news.yahoo.com/...yndrometiedtolowcortisollevels

autism Asperger Syndrome stress hormone Cortisol Asperger's Disorder Asperger

shared by Tero Toivanen on 04 Apr 09 - Cached
  • Low levels of a stress hormone may be responsible for the obsession with routine and dislike for new experiences common in children with a certain type of autism.
  • The body produces cortisol, among other hormones, in stressful situations. Cortisol increases blood pressure and blood sugar levels, among other duties, to signal the body's need to adapt to changes occurring around it.
  • People with Asperger syndrome notably have very repetitive or narrow patterns of thought and behavior, such as being obsessed with either a single object or topic. Though tending to become experts in this limited domain, they have otherwise very limited social skills, according to the study.
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  • "Although these are early days, we think this difference in stress hormone levels could be really significant in explaining why children with AS are less able to react and cope with unexpected change,"
  • If these Asperger symptoms are caused primarily by stress, caregivers could learn to steer children away from situations that would add to anxiety, the researchers said.
  • "This study suggests that children with AS may not adjust normally to the challenge of a new environment on waking,"
  • The researchers, whose findings were published in the journal Psychoneuroendocrinology, will next study if this lack of cortisol upon waking also occurs in children with other types of autism.
  • Tero Toivanen on 04 Apr 09
     
    Low levels of a stress hormone may be responsible for the obsession with routine and dislike for new experiences common in children with a certain type of autism.
Tero Toivanen

New Theory Of Autism Suggests Symptoms Or Disorder May Be Reversible - 0 views

www.sciencedaily.com/...090401145312.htm

autism new theory brain

shared by Tero Toivanen on 02 Apr 09 - Cached
  • the brains of people with autism are structurally normal but dysregulated, meaning symptoms of the disorder might be reversible.
  • autism is a developmental disorder caused by impaired regulation of the locus coeruleus, a bundle of neurons in the brain stem that processes sensory signals from all areas of the body.
  • The new theory stems from decades of anecdotal observations that some autistic children seem to improve when they have a fever, only to regress when the fever ebbs.
  • ...11 more annotations...
  • This study documented that autistic children experience behavior changes during fever.
  • Einstein researchers contend that scientific evidence directly points to the locus coeruleus–noradrenergic (LC-NA) system as being involved in autism. "The LC-NA system is the only brain system involved both in producing fever and controlling behavior," says co-author Dominick P. Purpura, M.D., dean emeritus and distinguished professor of neuroscience at Einstein.
  • The locus coeruleus has widespread connections to brain regions that process sensory information. It secretes most of the brain's noradrenaline, a neurotransmitter that plays a key role in arousal mechanisms, such as the "fight or flight" response. It is also involved in a variety of complex behaviors, such as attentional focusing (the ability to concentrate attention on environmental cues relevant to the task in hand, or to switch attention from one task to another). Poor attentional focusing is a defining characteristic of autism.
  • "What is unique about the locus coeruleus is that it activates almost all higher-order brain centers that are involved in complex cognitive tasks," says Dr. Mehler.
  • autism, the LC-NA system is dysregulated by the interplay of environment, genetic, and epigenetic factors
  • They believe that stress plays a central role in dysregulation of the LC-NA system, especially in the latter stages of prenatal development when the fetal brain is particularly vulnerable.
  • a higher incidence of autism among children whose mothers had been exposed to hurricanes and tropical storms during pregnancy.
  • autistic children, fever stimulates the LC-NA system, temporarily restoring its normal regulatory function. "This could not happen if autism was caused by a lesion or some structural abnormality of the brain," says Dr. Purpura.
  • future of autism treatment probably lies in drugs that selectively target certain types of noradrenergic brain receptors or, more likely, in epigenetic therapies targeting genes of the LC-NA system.
  • If the locus coeruleus is impaired in autism, it is probably because tens or hundreds, maybe even thousands, of genes are dysregulated in subtle and complex ways," says Dr. Mehler. "The only way you can reverse this process is with epigenetic therapies, which, we are beginning to learn, have the ability to coordinate very large integrated gene networks."
  • "You can't take a complex neuropsychiatric disease that has escaped our understanding for 50 years and in one fell swoop have a therapy that is going to reverse it — that's folly. On the other hand, we now have clues to the neurobiology, the genetics, and the epigenetics of autism. To move forward, we need to invest more money in basic science to look at the genome and the epigenome in a more focused way."
  • Tero Toivanen on 02 Apr 09
     
    the brains of people with autism are structurally normal but dysregulated, meaning symptoms of the disorder might be reversible.
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