Wojtkowska et al. (2024) investigated serum cf-nDNA levels in 30 PD patients and 15 NC by detecting the nuclear gene KRAS, revealing a non-significant elevation in cf-nDNA levels among PD patients after adjusting for age. In contrast, Scalzo et al. (2009) observed a significant reduction in cf-nDNA levels in PD patients compared to controls, based on detecting the nuclear gene β-globin in 42 PD patients and 20 controls. However, two cross-sectional studies from Chen M. et al. (2017) and Chen Y. S. et al. (2017) reported a significant increase in cf-nDNA levels in PD patients. Here, KRAS is linked to Parkinson disease.