More Autism News
Mutations continue to be the centerpiece of ASD research as scientists are constantly finding new information about how genes and their mutations interact to cause symptoms. The most recent study shed light on the true nature of a gene linked to autism, called AUTS2.
The study focused on disproving the belief that AUTS2 is the cause of autism’s social communication issues, and that a change in the mutation very rarely leads to autism, though it often paves the way for intellectual disabilities. Once the gene begins to be taken away, it could result in small heads, delays in development, a small chin, or arched eyebrows.
The researchers collected data from 13 participants between the ages of 11 months to 59-years-old. Three of the participants were from the original study starting in 2013, and all 13 had a type of cognitive disability. Eleven out of the 13 subjects had small heads and repetitive behavior, approximately 83 percent.
An additional conclusion of the study was that AUTS2 deletions at the beginning of the gene were much more mild than deletions at the end. At the end, the deletions were spontaneous, while they were slight and inherited from a parent at the beginning of the gene.
While the intellectual disabilities displayed in the study were potent from adolescence, they began to decrease with age.
Erik Sistermans is the lead of genome diagnostics at Vrije University Medical Center in Amsterdam, as well as the lead researcher of this study. He believes that as a researcher, he needs to share the conclusions with those outside of the autism research field.
“This is very important for genetic counseling,” Sistermans says. “It is important for parents to know that these children do not really deteriorate, that [the syndrome] is rather stable once they grow up.”
For more information, check out the source for this blog post, Spectrum News.
Mutations are often studied as the base of autism, with the Shank3 mutation being pointed out specifically as a leading cause of ASD symptoms. The Shank3 mutation is found in 0.5 percent of patients on the autism spectrum. A recent study, coming from MIT, pinpointed the main role that this common mutation plays in the disorder.
Neuroscientists from Massachusetts Institute of Technology used fruit flies as the test subjects in their recent ASD study. The flies were the best participants for the study because they only have one type of Shank out of the 3 total. This means that by the scientists eliminating the mutation from the flies, they eliminate the gene completely.
The main author of the study is Troy Littleton, a professor in the departments of Biology and of Brain and Cognitive Sciences at MIT, a member of MIT’s Picower Institute for Learning and Memory.
“It’s clearly regulating something in the neuron that’s receiving a synaptic signal, but some people find one role and some people find another,” Littleton said. “There’s a lot of debate over what it really does at synapses.”
Synapses are the connections between two separate nerve cells.
Littleton and his team found that postsynaptic cells had fewer areas for neurotransmitter releases, called boutons. These boutons often malfunctioned in the fact that there weren’t postsynaptic proteins like there were supposed to be. These proteins are meant to react to synaptic signals.
“During critical windows of social and language learning, we reshape our connections to drive connectivity patterns that respond to rewards and language and social interactions,” Littleton said. “If Shank is doing similar things in the mammalian brain, one could imagine potentially having those circuits form relatively normally early on, but if they fail to properly mature and form the proper number of connections, that could lead to a variety of behavioral defects.”
Another result of the study is that the disappearance of Shank can compromise specific proteins, translating into an issue with a signaling pathway, called Wingless.
For every few studies showing evidence that something leads to autism, there is always a study floating around with research disproving previous beliefs of possible ASD triggers. Recent research, stemming from Australia’s University of Queensland, focused on the long-studied idea of older fathers and their risk of giving birth to a child on the autism spectrum.
In the past decade, researchers have believed that men over the age of 50 that have children can increase the chance of having offspring with ASD due to mutations in their sperm that develop as they age. The study from The University of Queensland found that it’s more likely that men with any autism risk factors just end up conceiving late in their lives.
Two separate study conclusions were pushed together to form this belief. One study said that men over the age of 50 were two times more likely to have children with ASD than men under the age of 30. This coincided with the time that another study surfaced, saying that a man gains two random mutations, called de novo mutations, for every year he ages. These two conclusions were grouped together for the belief that older fathers increase the chance of autism.
The lead investigator of the newest study was James Gratten, a research fellow in neurogenetics and statistical genomics at the University of Queensland. He said that this belief was formed from assumptions of the two study conclusions.
“People have put two and two together and said that the extra mutations explain the increased risk in the children.” Gratten said.
Gratten and his team focused on mathematical models that incorporated multiple pieces of information such as the change of de novo rates with age, ASD and schizophrenia general rates, and how these are connected to hereditary and fertility effects.
With just 20 percent of the mutations linked to autism and schizophrenia from older male age, the researchers don’t find that the assumption holds too much water.
“The small number of additional mutations in children with older fathers can’t really explain the increase in risk that we see,” Gratten explains.
The models all figured that men between the ages of 35- to 39-years-old pass along 20 more mutations to their offspring than those in their 20s. Each model conveys different ideas of how strong de novo mutations have on ASD.
One of the main conclusions of the study is that older fathers actually contribute very little to the overall ASD rate. With the 20 percent of mutations leading to ASD, inherited factors contributing to about half of the risk, and ASD patients with children adding on another 35 percent chance, age-related mutations only account for 10 percent risk for older fathers.
For more information, check out the source for this blog post, Spectrum News.
The brain biochemistry is the centerpiece for the majority of most neurodevelopmental disorder research, including autism. Neurons, brain tissue, the interaction between lobes, it can all provide vital new information on these types of disorders. The most recent study focused on tracking down the issue of mislocated neurons.
The study found that sliding, independent microtubules play a hand in how neurons are distributed and reach their destinations throughout the brain. This discovery can shed light on how neurons go off path in disorders, such as autism.
The study took place at the Drexel University using electron tomography, the most effective available method for imaging. During the process, the researchers saw how several microtubules were not connected to the centrosome. These microtubules could be pushed around the neuron as it moves due to motor proteins.
Peter Baas, PhD, a professor in the College of Medicine, was the main investigator for the research study.
“This study is important for understanding how a healthy brain is organized,” Baas said. “If neurons do not know when to start migrating, or where to go, or if the axons don’t grow long enough, that sort of thing can give way to disorders such as autism.”
The researchers also applied a drug to the microtubules in order to immobilize them. This resulted in the neurons randomly changing their direction multiple times, as opposed to in a direct line.
“When we used the drug that inhibits sliding, we saw that the neuron can’t migrate in a nice straight, smooth trajectory,” Baas said. “That’s how we found out that little bit of sliding that normally occurs is really important for maneuverability.”
“If any of these mechanisms – with ninein or any of these motor proteins — are disrupted, there can be problems anywhere along the way,” Baas said.
These results proved that small changes to a neuron could translate into a big consequence, possibly leading to neurodevelopmental disorders.
Classification is important in all aspects of the science community because it allows researchers to divide up their results to do in depth analyzing of very specific topics. In the medical field, doctors and researchers use classification to determine the proper diagnosis and treatment for a patient. In the world of autism spectrum disorder, researchers and doctors have struggled to determine the different stages of communication issues with children on the autism spectrum.
Due to a study at McMaster University, social communication problems can finally be pinpointed into levels of severity. This will allow for better understanding of ASD social issues for individual children.
McMaster University’s CanChild Centre for Childhood Disability Research created a system that will show precisely how mild or extreme the social communication issues are in children with autism.
The system is called the Autism Classification System of Functioning: Social Communication that focuses on the child’s social communication skills, not lack of, like other methods have in the past.
The study was lead by Briano Di Rezze, a CanChild scientist and assistant professor of occupational therapy at McMaster’s School of Rehabilitation Science. She compares the variety classification of social communication skills to the color spectrum.
“This is not a test, but more like describing the colours of a rainbow,” Di Rezze said. “Currently we hear terms like ‘high-functioning’ or ‘low-functioning’ to describe children with ASD. However there is no common interpretation of what those terms mean, which makes them unreliable because clinicians, therapists, and parents aren’t using them in the same way.”
The system was built and tested by professionals and parents across the country. It was funded by a grant from the Canadian Institutes of Health Research.
The system uses “word pictures” to represent 5 levels of social communication in preschool children based off of what’s their best capacity and how they averagely perform.