“Our study of discordant twins – twin pairs in which only one twin was affected by ASD – found birth weight to be a very strong predictor of autism spectrum disorder,” said Northwestern University researcher Molly Losh.
Category Archives: Autism Causes
A study published in the Journal of Neuroscience and supported by grants from the National Institutes of Health and Autism Speaks has found that the loss of a specific mutated gene in the auditory cortical neurons – the powerhouses of the sound-processing center – causes hypersensitive to sound. While the functioning PTEN gene is known for it’s anti-cancer roll in powering down cell growth, proliferation, and survival, a mutated version of PTEN has the opposite effect and has been found in autistic individuals with macroencephaly, or an increase in brain volume. Previous work with the mutated form of PTEN in mice has resulted in boosted cell size and number of neurological connections in the brain.
Researchers at the Mailman School of Public Health at Columbia University have found that an uncommon bacterium exists in the walls of intestines of children with autism, but not those who do not have autism.The study, led by Brent Williams, tested 23 tissue biopsy samples from children with autism and found that a large portion (12 of the 23) contained the bacteria belonging to the group Sutterella. Even so, the bacteria are generally uncommon, not being found in any of the tissue samples from children without autism.
One of the many potential causes of autism, smoking during pregnancy, has been ruled out after a large population-based study in Sweden.“We found no evidence that maternal smoking during pregnancy increases the risk of autism spectrum disorders,” said study leader Dr. Brian Lee, an assistant professor at Drexel University and an epidemiologist at Drexel’s School of Public Health, in collaboration with researchers from Sweden’s Karolinska Institute and the University of Bristol (Bristol, UK).
A recent study shows the causes of autism to be more environmentally influenced than previously thought.
“This is a very significant study because it confirms that genetic factors are involved in the cause of the disorder,” said Dr. Peter Szatmari, a leading autism researcher who is the head of child psychiatry and behavioral neuroscience at McMaster University in Ontario. “But it shifts the focus to the possibility that environmental factors could also be really important.”
Little is known about the causes of autism and as recently as a few decades ago, psychiatrists thought autism was caused by a lack of maternal warmth. While it is currently thought that there are genetic explanations, there has been growing acceptance that genes do not paint the whole picture, partially because incidences of autism appear to be increasing faster than our genes can evolve.
There are questions over a possible autism epidemic given that the number of children diagnosed in the United States is twenty times higher than it was a generation ago. About one percent of all children are affected, according to the Centers for Disease Control.
Scientists are striving to determine an explanation for the spike in diagnoses. While there have been several red herrings, the search for an environmental explanation has so far been fruitless.
Roy Richard Grinker, an anthropologist at George Washington University who has studied autism across the world, believes that what some are calling an epidemic is really an “epidemic of discovery.” Grinker suggests that the percentage of people with autism has always been the same, but previously went undiagnosed or misdiagnosed.