June 03, 2026 —
Northwestern Medicine scientists have reported preclinical findings suggesting that a gene therapy approach may help reverse levodopa-induced dyskinesia, a common and difficult-to-manage complication in patients with late-stage Parkinson’s disease. The study was published in Neuron and identifies a specific synaptic mechanism that appears to drive abnormal involuntary movements associated with long-term levodopa treatment.
Levodopa remains the standard symptomatic therapy for Parkinson’s disease, helping replace dopamine as dopaminergic neurons are progressively lost. However, as the disease advances, many patients require higher doses, and most eventually develop levodopa-induced dyskinesia, or LID. These uncontrolled movements are thought to arise from abnormal changes in synaptic plasticity within the striatum, a brain region central to movement control.
In the new study, the Northwestern team found that LID depends on aberrant glutamatergic synaptic transmission in a subset of striatal neurons called indirect pathway spiny projection neurons, or iSPNs. Specifically, dyskinesia was associated with upregulation of GluN2B-containing NMDA receptors in these neurons, which are involved in suppressing unwanted movement.
Using a mouse model of LID, researchers showed that knocking down GluN2B mRNA in iSPNs not only prevented the development of dyskinesia but also reversed established dyskinesia. Importantly, the intervention did not reduce the symptomatic benefit of levodopa, suggesting that it may be possible to treat dyskinesia without compromising Parkinson’s motor symptom control.
The study also explored a gene therapy strategy to achieve this effect. Researchers used a specially designed viral vector delivered systemically to reduce GluN2B expression in the relevant striatal neurons. According to the investigators, this approach could potentially achieve a therapeutic endpoint similar to more invasive neurosurgical approaches, such as deep brain stimulation, without requiring brain surgery.
The findings remain preclinical, but they point to a novel therapeutic direction for Parkinson’s disease: correcting synaptic dysfunction rather than broadly suppressing dopamine signaling. If successfully translated, this strategy could offer a non-invasive gene therapy approach for patients with levodopa-induced dyskinesia, a condition estimated to affect a large proportion of patients receiving long-term levodopa therapy.
The research team is now working to organize an international consortium to further evaluate whether this approach could be developed for human use. While additional validation and safety studies will be required, the study provides a promising mechanistic foundation for a new class of therapies targeting dyskinesia at the synaptic circuit level.
