Scientists recreate nerve disease to study it

By Julie Steenhuysen

CHICAGO (Reuters) - U.S. scientists have created the first human model for studying a devastating nerve disease, which allows them to watch how the disease develops and could help researchers find a way to treat it.

Using skin cells from a child with spinal muscular atrophy, a genetic disease that attacks motor neurons in the spinal cord, researchers grew batches of nerve cells with the same genetic defects. The finding allowed scientists to watch the nerve cells die off.

"Now we can start from the beginning of development and replay the disease process in the lab dish," Clive Svendsen of the University of Wisconsin-Madison said in a telephone interview.

The finding, reported on Sunday in the journal Nature, marks the latest advance in research that reprograms ordinary cells to look and act like embryonic stem cells -- the master cells of the body that can produce any type of tissue or blood cell.

Spinal muscular atrophy is the most common cause of childhood death caused by a genetic mutation, Svendsen said. It is caused by a deficiency of a protein called SMN, for survival of motor neurons.

"That SMN protein is important for motor neuron survival. They are the cells that make muscles move," Svendsen said.

Infants with the most severe form the disease develop normally for the first six months of life, and then gradually develop muscle weakness and loss of motor control.

"They end up completely paralyzed," Svendsen said, adding they typically die around age 2.