On Sept. 15, 2023, a Northwestern Medicine study challenges a common belief in what triggers Parkinson’s disease. Degeneration of dopaminergic neurons is widely accepted as the first event that leads to Parkinson’s. But the new study suggests that a dysfunction in the neuron’s synapses – the tiny gap across which a neuron can send an impulse to another neuron – leads to deficits in dopamine and precedes the neurodegeneration.

Parkinson’s disease affects 1% to 2% of the population and is characterized by resting tremor, rigidity and bradykinesia (slowness of movement). These motor symptoms are due to the progressive loss of dopaminergic neurons in the midbrain. The findings were published in Neuron.

Northwestern scientists found that dopaminergic synapses are not functioning correctly in various genetic forms of Parkinson’s disease. This work, together with other recent studies by Krainc’s lab, addresses one of the major gaps in the field: how different genes linked to Parkinson’s lead to degeneration of human dopaminergic neurons.