Early stem cell mutation linked to autism

Washington, June 30 : A breakthrough study on mice has shown that mutations in neural stem cell development may be linked to autism.

Reported in the Proceedings of the National Academy of Sciences by experts at the Burnham Institute for Medical Research, the study showed that mice lacking the myocyte enhancer factor 2C (MEF2C) protein in neural stem cells had smaller brains, fewer nerve cells and showed behaviours similar to those seen in humans with a form of autism known as Rett Syndrome.

Dr. Stuart A. Lipton, a clinical neurologist who led the study, claims that his team's study represents the first direct link between a developmental disorder of neural stem cells and the subsequent onset of autism.

"These results give us a good hint of how to look at Rett Syndrome and potentially other forms of autism in humans. Having identified a mutation that causes this defect, we can track what happens. Perhaps we can correct it in a mouse, and if so, eventually correct it in humans," said Dr. Lipton.

Working in Dr. Lipton's laboratory, the research team observed that MEF2C turns on specific genes, which drive stem cells to become nerve cells.

The researchers also observed a faulty distribution of neurons, accompanied by severe developmental problems, when they deleted MEF2C from neural stem cells in the animals.

They have revealed that adult mice lacking MEF2C in their brains displayed abnormal anxiety-like behaviours, decreased cognitive function, and marked paw clasping, a behaviour which may be analogous to hand wringing, a notable feature in humans with Rett syndrome.

"There's a yin and yang to this MEF2C protein. My laboratory recently showed that MEF2C induces embryonic stem cells to become neurons. In this new research, we show that knocking out MEFC2in the brain results in mice with smaller brains, fewer neurons and reduced neuronal activity.

The commonality is the protein's association in making new neurons," said Dr. Lipton.

ANI