Scientists pinpoint molecular changes that could help to reveal people at risk of developing the disease before age 50.

Parkinson’s disease that develops in young and middle-aged people might be caused by cellular abnormalities present since birth.

About 10% of Parkinson’s cases are diagnosed in people who are 21 to 50 years old, among them film star Michael J. Fox, who was diagnosed at age 29. To find molecular markers of this ‘young-onset’ Parkinson’s, Clive Svendsen at the Cedars-Sinai Board of Governors Regenerative Medicine Institute in Los Angeles, California, and his colleagues reprogrammed blood cells from 22 people with young-onset Parkinson’s to make stem cells, which were then grown into brain cells.

These cells contained a build-up of α-synuclein proteins, thought to be toxic to neurons, and dysfunctional lysosomes, cellular structures that would normally clear the unwanted proteins. Because the problems could be traced back to the stem cells, the researchers suspect that the study participants were born with defective cellular machinery.

The researchers found that the drug PEP005 efficiently reduces the accumulations of α-synuclein in both cultured cells and the brains of live mice.