In some people with autism, researchers have pinpointed mutations in the DIXDC1 gene that impair synaptic growth and reduce brain activity.
Characterized by repetitive behaviors and problems with communication and social skills, autism is around 4.5 times more common among boys than girls.
Autism onset occurs before the age of 3 years and lasts throughout a person's lifetime. Some children may show signs of the disorder in the first few months of life, while for others, symptoms may not appear until 2 years or later.
There is currently no cure for autism or treatments that tackle the core symptoms, only behavioral therapies and medications that may improve functioning.
However, researchers from McMaster University in Canada believe they may be one step closer to the development of drugs that could combat autism at its root, after identifying how mutations in a gene called DIXDC1 impair the growth of synapses and impede brain activity.
Synapses are structures that enable signaling between nerve cells. Impairment of this signaling can disrupt normal functioning, which can lead to developmental and behavioral problems.
DIXDC1 gene mutation reduces synapse formation, brain activity
For their study, lead investigator Karun Singh - of the Stem Cell and Cancer Research Institute (SCCRI) and Michael G. DeGroote School of Medicine at McMaster - and colleagues conducted a genetic analysis of individuals with autism.
In a subset of people with the disorder, the researchers identified abnormalities in the DIXDC1 gene that stop the DIXDC1 protein from instructing brain cells to form synapses.
In detail, the researchers found that some individuals with autism possess mutations that cause the DIXDC1 gene to be "switched off," meaning synapses remain immature and brain activity is reduced.
The researchers are hopeful that their findings, published in Cell Reports, will advance the development of new medications that treat the core symptoms of autism.
"Because we pinpointed why DIXDC1 is turned off in some forms of autism, my lab at the SCCRI, which specializes in drug discovery, now has the opportunity to begin the searching for drugs that will turn DIXDC1 back on and correct synaptic connections. This is exciting because such a drug would have the potential to be a new treatment for autism."
While the DIXDC1 gene mutation is only found in a small number of individuals with autism and psychiatric disorders associated with the condition, the team notes that there are a number of other autism-related gene mutations that impair synaptic development.
"[...] therefore, the key to a new treatment for autism will be to find safe medications that restore brain cell synapse growth and activity," says Singh.