WASHINGTON (AP) — Scientists have found a new clue that Parkinson's disease may get its start not in the brain but in the gut — maybe in the appendix.

People who had their appendix removed early in life had a lower risk of getting the tremor-inducing brain disease decades later, researchers reported Wednesday.

Why? A peek at surgically removed appendix tissue shows this tiny organ, often considered useless, seems to be a storage depot for an abnormal protein — one that, if it somehow makes its way into the brain, becomes a hallmark of Parkinson's.

The big surprise, according to studies publish...