What are the genetic changes related to rapid-onset dystonia parkinsonism ?
Rapid-onset dystonia parkinsonism is caused by mutations in the ATP1A3 gene. This gene provides instructions for making one part of a larger protein called Na+/K+ ATPase, also known as the sodium pump. This protein is critical for the normal function of nerve cells (neurons) in the brain. It transports charged atoms (ions) into and out of neurons, which is an essential part of the signaling process that controls muscle movement.  Mutations in the ATP1A3 gene reduce the activity of the Na+/K+ ATPase or make the protein unstable. Studies suggest that the defective protein is unable to transport ions normally, which disrupts the electrical activity of neurons in the brain. However, it is unclear how a malfunctioning Na+/K+ ATPase causes the movement abnormalities characteristic of rapid-onset dystonia parkinsonism.  In some people with rapid-onset dystonia parkinsonism, no mutation in the ATP1A3 gene has been identified. The genetic cause of the disorder is unknown in these individuals. Researchers believe that mutations in at least one other gene, which has not been identified, can cause this disorder.