Study Identifies Beginnings of PD Prior to Patients Presenting With Symptoms

According to new research published this week, investigators have identified the earliest signs of Parkinson disease (PD) in the brain, years before patients present with any symptoms.

Identifying and subsequently studying the early stages of PD are crucial, as available treatments thus far are focused on slowing the progression of the disease. However, it has been difficult to detect PD prior to patients presenting with symptoms.

Researchers have previously discovered that patients with PD have build-ups of α-synuclein in the brain. Although, in most patients, researchers have not been able to identify a clear cause for this build-up, a minority of cases can be caused by rare genetic mutations. People with such mutations have a much higher likelihood of developing PD during their lifetime and therefore make good candidates for studying the biological events that lead to PD.

In this study, researchers recruited 14 patients with the A53T α-synuclein mutation (SCNA), 25 healthy controls, and 25 patients with idiopathic PD. In total, 7 (50%) of 14 A53T SCNA carriers were confirmed to have motor symptoms associated with PD, and the absence of motor symptoms was confirmed in the other 7 (50%) of the A53T SCNA carriers.

Data from these patients’ brain scans were compared with the other 2 cohorts, and the study investigators found that the serotonin system begins to malfunction in people with PD prior to the onset of motor symptoms and before the first changes in the dopamine system.

“We found that serotonin function was an excellent marker for how advanced [PD] has become. Crucially, we found detectable changes to the serotonin system among patients who were not yet diagnosed. Therefore, brain imaging of the serotonin system could become a valuable tool to detect individuals at risk for [PD], monitor their progression and help with the development of new treatments,” said Heather Wilson, MSc, of the Institute of Psychiatry, Psychology & Neuroscience, and lead author of the study, in a statement.

Reference

Wilson H, Dervenoulas G, Pagano G, et al. Serotonergic pathology and disease burden in the premotor and motor phase of A53T α-synuclein parkinsonism: a cross sectional study [published online June 19, 2019]. doi: 10.1016/S1474-4422(19)30140-1.