We don’t have a cure for Parkinson’s disease yet, but a recently discovered mutation in mitochondrial DNA that seems to protect the body against the condition could one day point the way to one. Discovered in a small protein called SHLP2, the genetic variant is relatively rare – found in just 1 percent of Europeans. Yet an analysis of the health records of 16,167 people led by researchers from the University of Southern California (USC) suggests…