Identifying Epigenetic Changes May Assist in Earlier Diagnosis of PD, Study Finds

Parkinson disease (PD) is the second most common neurodegenerative disorder found in the elderly, currently affecting an estimated 2% of individuals 60 years or older. PD is a multifactorial disease in which both environmental and genetic factors are significantly associated with disease onset. Although symptoms of the disease may present with a tremor or perhaps a speech problem, by the time the symptoms are evident, it is often too late to stop the progression of the disease.

A recent study, published in Epigenetics, demonstrated that identifying epigenetic changes may be used as a strategy to help assist physicians in making an earlier diagnosis.

“One of the biggest issues with neurodegenerative diseases like Parkinson disease or Alzheimer disease is that diagnosis is mostly clinical based, and it comes late in the disease—the brain is already degenerated, and it is extremely difficult to restore brain function at that stage,” said Travis Dunckley, PhD, assistant research professor at the ASU-Banner Neurodegenerative Disease Research Center and the School of Life Sciences, in a press release.

The study authors sought to investigate epigenetic changes in patients with PD over time, specifically any changes in DNA methylation patterns throughout the course of the disease. In order to identify these changes, the study enrolled 380 participants. The group was made up of 189 patients with PD and 191 control subjects.

Follow-up time was 2 years, during which no changes in cognition were identified in the control group, whereas patients with PD demonstrated decay in Mini-Mental State Examinations (MMSE). Researchers found differences in methylation patterns for those subjected to anti-Parkinson drugs compared with those who did not receive treatment. Additionally, the study authors also found that DNA methylation changed more for those patients without treatment, providing further evidence to the link between epigenetics and PD progression.

If the investigators are able to identify the distinct changes in methylation related to PD progression, they would be able to diagnose the disease earlier. According to the authors, future studies will be similar to this; however, they will take place over a longer duration and with a new subset of patients.

“Taken in all, these studies support the potential of blood DNA methylation as an epigenetic biomarker of disease, although additional profiling of large longitudinal cohorts is needed to complete the characterization of DNA methylation changes during the onset and progression of Parkinson’s disease,” wrote the authors.

Reference

Henderson-Smith A, Fisch K, Hua J, et al. DNA methylation changes associated with Parkinson’s disease progression: outcomes from the first longitudinal genome-wide methylation analysis in blood. Epigenetics. 2019; 14(4):365-382. doi: 10.1080/15592294.2019.1588682