Scientists in Japan have tweaked the chromosomes of mice to make the animals act autistically. The engineered rodents display genetic impairments and behavior that mirror those of some humans with the disorder.

The work, published in Cell, provides direct evidence linking chromosome abnormalities (believed to be responsible for approximately 10% of autism cases) and autism.  In some people with autism, a specific region of human chromosome 15 is doubled.

Jin Nakatani, Kota Tamada, and their colleagues duplicated the corresponding fragment of a mouse chromosome. Mice carrying the extra DNA were, among other things, less social, louder when communicating, and better at repetitive tasks. Those behaviors are common in people with autism. 

The group went on to look for molecular differences between the brains of the autisticlike mice and the control mice. Their results suggest that the autistic mice may have an altered receptor for serotonin, called 5-HT2c. Serotonin has previously been linked to autism because of its function in the developing brain.

The researchers believe that these mice will not only serve as a model for developing treatments to autism but that they will be useful in understanding other brain problems.

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