November 2013 has been an enormous month for developments in autism research, mostly the identification and mapping of the group of genes that are involved in the onset of autism and ASDs.
Dr Daniel Geschwind headed up a group of neuroscientists researchers at the UCLA have mapped the cells by function and pin pointed the exact location in the brain and when they are likely to cause brain function to change during foetal development.
In addition, they discovered disturbances in neural circuits that define key pathways between parts of the cerebral cortex that are known to be involved in autism.
The research suggests that these disruptions are created by mutations in genes during foetal brain development and are not a result of autism itself.
The work published alongside UCSF’s research on November 21 in The Cell Journal , lead researcher Dr Geschwind said:
“Identifying gene variants that boost risk is only the first step of unravelling a disease. “
David Geffen School of Medicine at UCLA and professor of psychiatry at the Semel Institute for Neuroscience and Human Behavior said:
“We need to figure out where genetic changes appear in the brain, at what stages during development they occur and which biological processes they disrupt. Only then will we understand how mutations cause autism.”
Authors looked at the BrainSpan atlas, gene mapping program and isolated the risk genes at different developmental stages from eight weeks to 12 months of age, particularly looking at when cells replicate and when they transfer DNA and RNA to produce proteins.
Researchers were able to isolate two periods of development where the at risk genes were highly active. First author Neelroop Parikshak, a graduate student researcher in Geschwind’s lab said.
“We found that gene variants are expressed in the developing brain when cells define their future identities and roles in neural circuits. Therefore, changes in the genes influence the brain’s wiring by altering the synapse and shaping how neurons transmit signals to each other.”
They also found that the mutated genes also interfered with how both half of the brains communicated directly to one another. Dr Geshwind said:
“We discovered gene-related disruption of circuits that connect the autistic brain’s layers and hemispheres to each other.
Our finding suggests that the mutated genes caused the miswiring; it’s not a result of having the disease itself.”