The effect of polygenic risk on white matter microstructural degeneration in Parkinson's disease: A longitudinal Diffusion Tensor Imaging study

• Published in: European journal of neurology Vol. 29; no. 4; pp. 1000 - 1010
• Main Authors: Gu, Luyan, Guan, Xiaojun, Gao, Ting, Zhou, Cheng, Yang, Wenyi, Lv, Dayao, Wu, Jingjing, Fang, Yi, Guo, Tao, Song, Zhe, Xu, Xiaojun, Tian, Jun, Yin, Xinzhen, Zhang, Minming, Zhang, Baorong, Pu, Jiali, Yan, Yaping
• Format: Journal Article
• Language: English
• Published: England John Wiley & Sons, Inc 01.04.2022
• Subjects: Cognition; Cognitive ability; Data acquisition; Degeneration; Depletion; Diffusion tensor imaging; Dopamine; Dopamine receptors; Gene frequency; Health risk assessment; Magnetic resonance imaging; Mathematical analysis; Medical imaging; Microstructure; Movement disorders; Neurodegeneration; Neurodegenerative diseases; Neuroimaging; Nucleotides; Parkinson disease; Parkinson's disease; Patients; Polygenic risk; Radiation; Risk; Single-nucleotide polymorphism; Substantia alba; Tensors; Thalamus; White matter microstructure; Parkinson disease; Polygenic risk; Diffusion tensor imaging; White matter microstructure
• ISSN: 1351-5101; 1468-1331
• DOI: 10.1111/ene.15201

Background and purpose This study was undertaken to investigate the effect of genetic risk on whole brain white matter (WM) integrity in patients with Parkinson disease (PD). Methods Data were acquired from the Parkinson's Progression Markers Initiative (PPMI) database. Polygenic load was estimated by calculating weighted polygenic risk scores (PRS) using (i) all available 26 PD‐risk single nucleotide polymorphisms (SNPs) (PRS1) and (ii) 23 SNPs with minor allele frequency (MAF) > 0.05 (PRS2). According to the PRS2, and combined with clinical and diffusion tensor imaging (DTI) data over 3‐year follow‐up, 60 PD patients were screened and assigned to the low‐PRS group (n = 30) and high‐PRS group (n = 30) to investigate intergroup differences in clinical profiles and WM microstructure measured by DTI cross‐sectionally and longitudinally. RESULTS PRS were associated with younger age at onset in patients with PD (PRS1, Spearman ρ = −0.190, p = 0.003; PRS2, Spearman ρ = −0.189, p = 0.003). The high‐PRS group showed more extensive WM microstructural degeneration compared with the low‐PRS group, mainly involving the anterior thalamic radiation (AThR) and inferior fronto‐occipital fasciculus (IFOF) (p < 0.05). Furthermore, WM microstructural changes in AThR correlated with declining cognitive function (r = −0.401, p = 0.028) and increasing dopaminergic deficits in caudate (r = −0.405, p = 0.030). Conclusions These findings suggest that PD‐associated polygenic load aggravates the WM microstructural degeneration and these changes may lead to poor cognition with continuous dopamine depletion. This study provides advanced evidence that combined with a cumulative PRS and DTI methods may predict disease progression in PD patients. This study combined polygenic risk score (PRS) and longitudinal diffusion tensor imaging (DTI) data to investigate the effect of genetic risk on white matter (WM) integrity in patients with Parkinson disease (PD). We found PRS was associated with younger age at onset in PD patients, and the high‐PRS group showed more extensive WM microstructural degeneration, mainly involving the anterior thalamic radiation (AThR) and inferior fronto‐occipital fasciculus (IFOF). Furthermore, WM microstructural changes in AThR may lead to poor cognition with continuing dopamine depletion.