Ephrin-B3 protein linked to mirror-movement disorder

Researchers from the University of Texas Southwestern Medical Center found that mice lacking the protein ephrin-B3 showed signs of a rare condition known as mirror-movement disorder.

The main symptom of the disease is an involuntary symmetrical movement of the limbs so, for example, when the right hand is moved the left involuntarily moves with it.

Previous research has suggested that mirror movement is caused by defects in the corticospinal tract, and ephrins are known to regulate nerve growth within this tract. Mark Henkemeyer explains in January Neuron: "Ephrin-B3 is a very important molecule as it is expressed down the middle of the spinal column. It serves as a repulsive barrier that keeps the left axons on the left side of the nervous system and the right axons on the right." Henkemeyer's group reports that mice genetically engineered to lack the ephrin-B3 protein display a kangaroo-like hopping gait involving both...