Thursday, May 04, 2006

Pten gene knockout and "autistic" mice

[See the updates. The BBC article is misleading about why this is important.]

Knocking out a gene in mice [suspected to be involved in some autism in humans] creates a wide range of behavioral disorders that bear some resemblance to a part of "autism" in humans:
BBC NEWS | Health | 'Autistic' mice offer gene clue

... The University of Texas team looked at mice where the Pten gene - which has already been linked to other brain disorders - was deleted in the mature nerve cells in the cerebral cortex and hippocampus areas of the brain.

These regions are associated with higher brain function such as learning and memory.

The mice behaved in a number of socially abnormal ways, compared to another group of mice from the same litter.

The genetically altered mice were socially less skilled, being far less likely to be curious about new animals coming into the cage.

... The genetically altered mice were also less likely to build nests or look after their young, but were more sensitive to stressful stimuli, such as loud noises or being picked up.

An examination of their brains showed they also had the increased brain volume and enlarged heads seen in people with autistic spectrum disorders.
At the least this will help us with understanding how the brain works and develops. It is way premature to suggest a connection with autism. Removing the visual cortex also impairs one's social responses; social function is very high level and requires a lot of things to work properly. Any cognitive knockout will impair it.

We should hear fairly soon if there's a subtype of "autism" (whatever that is) that has problems with this particular gene, and whether it somehow affects "mirror neurons" (whatever they are) more than other neurons.

Update 5/4/06: I googled on [Pten Autism]. Turns out there's reason to suspect this gene is related to the 'big head' subtype of autism in humans. The researchers were probably doing the knock out in mice to f/u on that theory. So the connection is more plausible than the BBC report alone suggests. I search on [Pten "mirror neuron"] finds the two terms appearing on news pages together, but as of this moment I didn't get a hit that found a specific mirror neuron problem related to Pten. My old speculation has been that "mirror neuron" depletion might be a secondary response to a deeper defect, a kind of "salvage" or "scavenging" response to a deeper injury.

Update 5/4/06b: Ok, I'm sorting this out. I think this is big news in the near term. If these researchers have created a "mouse model" for a subtype of autism then we've made a big advance in understanding and either preventing or (less likely) treating autism. It's impossible for a non-evil society to experiment on humans, or even primates. We still consider mice to be fair game. They reproduce quickly, their cheap, and we understand their biology very well.

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