How Mutations in the Parkin Gene Affect Quality of Life in Patients With Parkinson Disease

Newly diagnosed patients with Parkinson disease (PD) who carried mutations in the Parkin gene were found to exhibit worse quality of life (QOL), longer disease duration, and an earlier age at disease onset than those with PD who did not carry the mutation, according to study findings published in Frontiers in Neurology.

As the researchers of the study note, mutations in this gene have been indicated as the most common cause of autosomal recessive early-onset PD, accounting for 10.1% of patients with disease onset before the age of 40 in the Asian population.

Although studies have reported a link between younger age of PD onset and poor QOL, the researchers say that little is known about potentially differing QOL aspects in patients with monogenic forms of PD, chiefly PD caused by Parkin mutations.

“Reduced QOL as an important aspect of PD is getting more and more attention, and the improvement in QOL has been increasingly acknowledged as a vital objective in the management of PD,” highlighted the study authors.

Seeking to better understand the patterns of QOL in patients with and without Parkin-related PD, the researchers recruited patients with newly diagnosed PD (diagnosis made within 12 months) who were younger than 40 years (n = 148). Participants underwent PD-related genetic testing, and 24 were found to carry bi-allelic variants in the Parkin gene. These patients were then matched and compared with 24 patients who did not have any known causative PD mutations or risk variants.

In their findings, patients with Parkin-related PD were found to be younger at age of onset (P = .003) and have longer disease duration (P = .005) than those without any PD mutations or risk variants.

After adjusting for disease duration and age of onset, those with Parkin-related PD were found to have more dystonia (P = .034) and worse scores of nonmotor symptoms than those without mutations, including on the Beck depression inventory (P = .035), Epworth sleepiness scale (P = .044), and subdomains of depression and anxiety (P = .015) and sleep disorders (P = .005) on the nonmotor symptoms questionnaire.

Those with Parkin-related PD were shown to have poorer QOL (adjusted P = .045) than those without any mutations, with mobility (adjusted P = .025), emotional well-being (adjusted P = .015), and bodily discomfort (adjusted P = .016) indicated as notable factors. Moreover, scores on the Beck depression inventory (P = .005) and Epworth sleepiness scale (P = .047) were found to be significant determinants of QOL in patients with Parkin-related PD.

“For clinicians, management of depression and excessive daytime sleepiness is suggested to better improve QOL in patients with Parkin mutations,” concluded the study authors.

Reference

Zhou XY, Liu FT, Chen C, et al. Quality of life in newly diagnosed patients with Parkin-related Parkinson disease. Front Neurol. Published online December 18, 2020. doi:10.3389/fneur.2020.580910