Despite widely held beliefs autism and obsessive-compulsive disorders may be linked to factors other than genetics.
When researchers removed the protein FKBP12, found in both humans and mice, from studied mice, the animals demonstrated major neurological and behavioral changes.
FKBP12 is known to regulate the activity of mTOR, an enzyme that affects the ability to change behavior and regulates connections between neurons, thus playing a key role in learning and memorization.
The findings of the study, led by researchers at New York University's Center for Neural Science and the Baylor College of Medicine, may enhance scientific and medical understanding of disorders such as autism, which affects about one in 150 children in the United States, according to the US Centers for Disease Control and Prevention.
Results showed an increase of mTOR signaling after removing the protein from the brains of mice late in development. The mice also demonstrated an enhanced ability to change connections between neurons, especially in those parts of the brain used for memory.
Removing FKBP12 reduced the mice's capacity to analyze, respond and adapt to new situations, according to the study.
Once the mice learned a task, such as navigating a maze, they had difficulty learning how to travel through a different version of the maze. This type of enhanced perseveration, or pathological repetition, is often observed in individuals suffering from autism or other neurological disorders.
"Our results suggest that FKPB12 regulates neuron signaling that curbs the manifestation of traits observed in several neurological disorders including autism, obsessive-compulsive disorder and schizophrenia," said NYU neuroscientist Eric Klann, the study's lead researcher.
These disorders are widely believed to be "determined in utero by genetic hormonal and environmental factors," he adds.
But "because our study indicates that postnatal release of mTOR activity can result in certain perseverative behaviors, it challenges the idea that some aspects of these conditions are developmentally predetermined."