MET Gene Variant Links Autism and GI Disorders

Autism in children
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Researchers at the University of Southern California and Vanderbilt University have identified a specific gene variant that links autism with gastrointestinal conditions. Their study is published in the March issue of the journal Pediatrics.

Autism is a developmental disorder characterized by deficits in communication abilities, social behavior disruption and inflexible behavior. Many children with autism have been noted to have GI problems. This led the researchers to hypothesize if the ones with the GI problems represented a subset of autism.

The researches chose to look at a functional variant in the promoter of the gene encoding the MET receptor tyrosine kinase. It is known to be associated with autism spectrum disorder. MET is a pleiotropic receptor that functions in both brain development and gastrointestinal repair. In the brain, the MET gene is expressed in developing circuits that are involved in social behavior and communication. Disturbances in MET expression result in alterations in how these critical circuits develop and mature.

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Researches studied the medical records of 918 individuals from 214 Autism Genetics Resource Exchange families. These records included a complete medical history and gastrointestinal condition report. They found that a variant in the MET gene was associated with autism specifically in those families where an individual had both autism and a gastrointestinal condition.

Levitt states, “Gastrointestinal disorders don’t cause autism. Autism is a disorder of brain development.”

The study helps provide a biologically plausible explanation for why autism and GI disorders are often seen together.

The study was funded by the Simons Foundation, the Nancy Lurie Marks Foundation, the Dan Marino Foundation’s Marino Autism Research Institute, the National Institute of Mental Health and the National Institute of Child Health and Human Development.

Source
University of Southern California News
Distinct Genetic Risk Based on Association of MET in Families With Co-occurring Autism and Gastrointestinal Conditions; Pediatrics, 10.1542/peds.2008-0819; Daniel B. Campbell, Timothy M. Buie, Harland Winter, Margaret Bauman, James S. Sutcliffe, James M. Perrin, Pat Levitt.

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Thoughts Regarding Autism Spectrum Neurodevelopmental Disorders Of these rare neurological disorders, Autism is the most common. The autism spectrum reflects the broad range of symptoms in which the names of these autism disorders have been given their own name for their disorder. Autism is a disability that is suspected to be caused possibly by a brain development disorder of unknown etiology. Others suspect the cause is some sort of neurological dysfunction- possibly with a genetic predisposition. Autism is about 3 times more common in males than females as well, and it is unclear as to why this occurs. Usually, symptoms of the disease present themselves before the toddler reaches the age of three. Before Autism was more understood, others inaccurately labeled autistic people as childhood schizophrenia or as having a psychosis or mental retardation. Symptoms of the autistic patient included limited or dysfunctional social and personal or intimate relationships with others, their intelligence is affected, and the autistic person typically is adverse to change. Also, the autistic person tends to be compulsive and prefers to be alone. They lack eye contact as much as physical contact with other people. Out of over two dozen diagnostic criteria utilized for these disorders, eight must be present to be considered autistic, according to the DSM. As with all passive developmental disorders, the person expresses language, social, and behavioral difficulties. Treatment includes what are called psychotropic medications that delay the progression of the disorder, as well as relieve some of the symptoms of one who is autistic. Behavioral therapy is common as a treatment regimen as well. Boys get Autism much more than girls. Then there is the controversy between many who claim that thimerosal- a preservative containing mercury, which is a neurotoxin that was used in vaccines until 2001, was the catalyst for autism in children. Over 5000 lawsuits have been filed because of this belief, and some have been successful for the plaintiff. Yet most agree the correlation between thimersal and autism is void of scientific merit. Furthermore, the cases of autism have not decreased since the preservative was discontinued in 2001. Aside from Autism, the other four passive developmental disorders are known as autism spectrum disorders. Asperger’s Syndrome is more common than autism, and the symptoms are milder, as there is minimal delay in language abilities, if at all. What is expressed with Asperger’s syndrome is mild autistic symptoms. In time, the patient may express atypical personality disorders, though. While intelligence is within normal limits with the Asperger’s patient, social interactions and abilities preset difficulty for such a patient. As with Autism, medications and behavioral therapy are treatment regimens with one with this syndrome Rett’s Syndrome or disorder presents with not only atypical behavior, but also suffers from restricted physical growth and movement. There is cognitive and social impairment as well. The disorder affects mostly girls, and the cause is due to a gene mutation. Childhood Disintegrative disorder is rare, and is 10 times less common than autism. The disorder has a late onset with mild autistic symptoms. The disorder affects mostly boys, and regression is sudden and possible with this disorder. Skills lost with this disorder may be language, social, self-care, as well as play or motor skills. Decreased function or impairment with this disorder may include social skills and behavioral flaws. Central Nervous System pathology is a suspected cause of this disorder. Finally, there are passive development disorders that are not otherwise specified. This may include atypical autism, for example. Yet as with the rest of types of these disorders, the symptoms vary in their frequency and intensity, as well as the range of abilities of these developmental disorders vary widely as well. Medicinal treatment is believed to be not necessary for the management of all of those who may have autistic spectrum disorders. Depending on the patient’s health care provider, medications may be prescribed by their doctor to manage any affective disorders autistics may present in an acute or chronic nature. However, cognitive and behavioral therapy prove to be most beneficial for all the different types of Passive Development Disorders that exist for reasons yet to be defined. Dan Abshear
"Because ASDs have at their core disrupted brain development, in terms of etiology, both genetic and environmental influences must play roles because this is in the basis for brain development." ... “Finally, if we are going to understand functional etiology of ASD, if we are trying to identify the genes that underlie risk, and we are searching for environmental factors that cause changes in brain development, we need to know where these candidate genes are expressed in the developing human brain, and where these environmental factors have their impact.” ... “This is a relatively common variant, seen in about 47 percent of the population,” Levitt said. “So why doesn’t everybody have autism?” Because of environmental and other genetic contributions, he said. “Genes create a vulnerability that then gets coupled with some environmental disturbance — but right now, we don’t have any idea what those factors might be.” A UC-Davis study by Pessah et al. showed that ethylmercury from Thimerosal damages dendrites at less than 40 parts per billion. Most injectable flu vaccines contain 50,000 ppb ethylmercury. Read the MSDS for Thimerosal -- it is a mutagen and a teratogen, and still used in vaccine manufacture (except the MMR) but chelated before shipping.