14 DAY TRIAL // Neuroscientists at the Massachusetts Institute of Technology (MIT), in Cambridge, say that they were recently able to identify the single genetic mutations that are responsible for the development of several conditions in the autism spectrum (ASD).
The finding is bittersweet in a way, since scientists addressed conditions such as Asperger's syndrome and Fragile X syndrome, and not autism itself. The main condition's genetic causes are still shrouded in mystery, even though researchers have made considerable progress over the past few years.
Past studies have already identified a number of genetic factors and variants involved in the development of autism. What this implies is that the disease does not have a single point of origin, but rather is the result of a combination of factors.
Some of the actors involved in this interplay are glitches occurring inside synapses. These are the areas connecting two neurons together, allowing for electrical signals to be transmitted from one nerve cell to the next cell. Autism and related disorders all display glitches in synaptic transmission.
MIT neuroscientist and study author Mark Bear published details of the new discovery in the November 23 issue of the top scientific journal Nature. His investigation also included a portion in which the team focused on a condition called tuberous sclerosis.
While extremely rare, this disease affects the brain significantly, and is usually accompanied by both mental retardation and autism. Bear managed to show that proteins found in brain synapses were produced in very low concentrations in this disorder.
Taking the new data into account, the theory holding that autism is nothing more than the end result of a host of brain-synapse glitches coming together gains new strengths. “The general concept is that appropriate brain function occurs within a very narrow physiological range that is tightly maintained,” the investigator says.
“If you exceed that range in either direction, you have an impairment that can manifest as this constellation of symptoms, which very frequently go together – autism spectrum disorder, intellectual disability and epilepsy,” Bear adds.
The investigator holds an appointment as the Picower professor of neuroscience at MIT, and also as a member of the MIT Picower Institute for Learning and Memory. He says that this study accidentally led him to learn how Fragile X syndrome develops as well.
In the case of FXS, the condition is caused by too many proteins in the synapses, the investigator concludes.