Detected gene mutation for autism?
Certain forms of autism may be caused by mutations in the Pten gene. This is what US researchers suspect after experiments with mice that, after switching off the gene in the brain, showed social deficits similar to those known from people with autistic disorders.
The experiments were aimed at Pten because it was noticed that some patients with autism have mutations in this gene. So Luis Parada of the University of Texas and his colleagues silenced the gene in mature neurons in the hippocampus and cerebral cortex of mice to observe the effect.
Unlike their untreated conspecifics from the same box, who were curious and open-minded about new cage mates, these mice would have shown themselves to be totally uninterested in the newcomers after the procedure. They were also more likely to turn to offered items than the control animals, who were more likely to seek contact with others. According to Parada, the animals behaved in a similar way to autistic people, who often prefer toys to social contacts. The modified rodents also completely ignored the offered nesting material, while their normal conspecifics immediately used it to build their nests. Offspring of the mutants died more often due to maternal neglect.
More detailed studies of the brain also revealed that in the brain areas with silenced Pten, the nerve cells are thicker than normal and they had an exceptionally large number of connections to other nerve cells. According to the researchers, this could explain the higher sensitivity of these animals to stimuli.
Pten is one of the so-called tumor suppressor genes: the enzyme it encodes plays an important role in controlling cell division.
