Gamma waves are brainwave activity at a certain speed and have been linked to consciousness and seem to help coordinate activity in different parts of the brain. They have also been associated with processing of information, including sensory information. This week, researchers at Oxford University led by Dr. David Menassa explore gamma waves in the brains of autistic adults who perform better on a visual processing task than those without a diagnosis. Gamma waves are controlled by the coordinated activity of neurons in the brain, which are regulated by inhibitory interneurons which make sure excitatory neurons aren’t taking over. In a study using brain tissue of people with autism, it was found by another study at Oxford that there are fewer of these inhibitory interneurons to control this activity. Dr. David Menassa provides his own interpretation of the data on this week’s podcast.
This week’s podcast focuses on two studies that help illustrate why studying individuals with a specific genetic mutation, or animal models with a particular genetic mutation, are so important. MSSM researchers focused on individuals with FOXP1 Syndrome, which has a high rate of autism and could be the focus of future treatments. In the meantime, researchers at UTSW, led by ASF fellow Christine Ochoa Escamilla, identified a particular brain chemical responsible for changes in brain activity following mutations of chromosome 16. About 1% of people with autism have mutations in this chromosome. Application of a chemical to counteract this chemical then led to improvements in brain activity, opening up the door to new drug targets that affect some of the more severely affected individuals with ASD.
Here are the references: https://www.ncbi.nlm.nih.gov/pubmed/29088697
One of areas of genetic interest of autism is a region of chromosome 15. Only about 3% of people with autism have the mutation, but 80% of those with the mutation have autism. It is so important that people with duplications of this area have formed their own advocacy group called the Dup15 Alliance. I was honored to attend their family an scientific meeting and give a summary of what scientists have learned about autism through studying this chromosome, how kids with this mutation and autism are similar and different from those with autism but not the mutation, how the families are managing life threatening seizures, what the gene does, what the brains look like, and how mutations of this chromosome do in fact interact with the environment. Thank you to the scientists who study this area and the very brave, selfless and amazing parents who I talked to.
Yes, another type of mutation in autism was revealed this week. Those that are evident after the sperm and egg meet to form the zygote but still very early, during embryonic development. Because it occurs after the original zygote is formed, the mutation is not found in every cell or every region of the body, called post-zygotic. A collaboration of three major genetic consortia studied and collaborated on these types of mutations and revealed that they consist of about 7.5% of all de novo mutations in people with autism. They affect autism risk genes and selectively target brain regions associated with autism. Learn more about what this means for family planning and cognitive ability in people with autism.
This week, autism lost a pioneer and advocate for autism research: Isabelle Rapin, MD, a neurologist from New York’s Albert Einstein University. The first part of the podcast is a brief summary of her accomplishments. The second part is an study called “how to keep your child out of the hospital”, presenting a recent study which looked at risk factors for being an inpatient, rather than an outpatient. These risk factors may not be able to be prevented, but hopefully through identification of what they are, situations might be managed to help those with autism and their families during a crisis situation.
On May 4th, Dr. Janine LaSalle from UC Davis and (the soon to be Dr.) Keith Dunaway presented on recent research investigating the role of environmental factors in individuals with Dup15 Syndrome. Individuals with a mutation on chromosome 15 are often diagnosed with autism and previously it had been assumed that these individuals were destined to have a diagnosis due to their genetics. Dr. LaSalle shows that many of the genes in a critical region of chromosome 15 are tied to turning genes on and off via a process called methylation. Environmental chemicals or other exposures may also work on these genes to turn on or off gene expression epigenetically. The first half of the webinar reviews crucial ideas in gene x environment interactions and epigenetics, the second half describes experiments using brain tissue of those with Dup15 Syndrome and autism, as well as cell lines, to understand the role of PCBs in gene expression.
Last week CNN.com reported on a study that showed slight improvement of autism symptoms in children that received a single infusion of their own umbilical cord blood. While the study was interesting, the authors were the first to acknowledge the limitations, however, this did not stop the media from misrepresenting the results. Details are explained in this podcast. In addition, a big win this week for precision or personalized medicine: different symptoms and different genetic mutations are linked to different outcomes from different anti-seizure medications.
Last week, another Baby Siblings Research Consortium Project (BSRC) published an intriguing finding which also has the bonus of being a replication. Mark Shen, PhD, from the University of North Carolina at Chapel Hill found higher levels of extra axial fluid in the brains of infants who went on to later be diagnosed with autism, and even higher levels in those with severe autism symptoms. Extra-axial fluid is also called cerebrospinal fluid, the fluid that holds the brain steady in your head. Other functions of extra-axial fluid and what this means on how it may contribute to autism risk are described in the podcast. He not only explains the findings, but conveys what families should know about them and how they can help with early identification of ASD.
This week the Infant Brain Imaging Study, or IBIS, published it’s 2nd study on the emergence of changes in the brains of individuals with autism. While red flags for autism can be seen early, a diagnosis of autism is not typically made until after 24 months of age. Using a baby sibling research design, scientists showed increases in the size of certain areas of the brain between 6-12 months. This opens up opportunities for even earlier diagnosis of ASD in the future. Also, a group at Stanford shows the emergence and disappearance of co-morbid symptoms in autism, such as epilepsy, schizophrenia and ADHD, which are dependent on sex and age. Together, these studies show that autism begins very very early and symptoms and behavioral and biological features change over time.
Even though more than 20% of people with autism have little or no language, research into ways to help this group have really been lacking. Several efforts to not just understand the abilities and disabilities of this group started a few years ago and we are just starting to hear about what works and what doesn’t work to improve communication in those with little or no language. This podcast summarizes the evidence, which points to combinations of things, rather than things in isolation, and peeks in on ways in which interventions can be better directed and made more effective.