A Parkinson's discovery in a single brain cell — and a clue the brain may fight back

Parkinson's disease kills the brain's dopamine neurons, and nobody fully understands why those cells are so vulnerable. Researchers at the University of Birmingham and Newcastle University have now sequenced the mitochondrial DNA of individual brainstem neurons — the first single-cell study of its kind — and found extensive damage, but also something encouraging: a protective response involving the quality-control gene PINK1, strongest in people who lived longest after diagnosis. Published in the journal Brain, the work could point to ways of strengthening the brain's own defenses against the disease that affects more than 10 million people worldwide.