Evaluation of Micronucleus in Buccal Mucosa Samples as a Potential Biomarker for Early Diagnosis of Parkinson’s Disease: A Cross-sectional Study

Introduction: Parkinson's Disease (PD) is the second most prevalent neurodegenerative disease as of 2024, with a global prevalence of 1.51 per 1,000 people in 2023. Micronuclei are small structures formed when chromosome fragments or whole chromosomes are not properly incorporated into the daughter nuclei during cell division. Their presence can signal genomic instability, which may be linked to neurodegenerative diseases such as PD. The buccal micronucleus assay is a cytogenetic test that examines micronuclei in cells from the buccal mucosa, offering insights into genetic damage or chromosomal instability, and it has been explored as a potential diagnostic tool for PD. Aim: To compare the presence of micronuclei in the buccal mucosa samples between individuals with PD and healthy controls, as a potential non invasive indicator for early PD detection. Materials and Methods: This cross-sectional study was conducted in the Department of Neurology at NIMHANS Hospital, Bengaluru, Karnataka, India from March 2023 to February 2024. A total of 170 participants, including both individuals with PD and healthy controls, were recruited from the Outpatient Department (OPD) and PD wards of NIMHANS Hospital. Buccal mucosa samples were collected using a moistened wooden tongue spatula, fixed onto glass slides with biofix spray and stained using the Papanicolaou (PAP) method. Microscopic images of these slides were then analysed quantitatively using an image analyser, focusing on the presence of micronuclei in the buccal epithelial cells. Results: The mean age of the healthy group was 66 years, while the mean age of the Parkinson’s group was 60 years, with an overall mean age of 63.14 years. The gender distribution in the healthy group included 38 males and 47 females, whereas the Parkinson’s group consisted of 55 males and 30 females. Among the study participants, the frequency of micronuclei occurrence was higher in Parkinson’s patients (69.4%) compared to healthy controls (11.8%). Conclusion: The occurrence of micronuclei was notably greater in individuals with PD when compared to healthy controls, suggesting a higher rate of genomic instability in PD patients. This observation reinforces the potential of micronucleus frequency as a useful biomarker for PD.