Genetic landscape of human mitochondrial genome using whole-genome sequencing.

Increasing evidences suggest that mitochondrial dysfunction is implicated in diseases and aging, and whole-genome sequencing (WGS) is the most unbiased method in analyzing the mitochondrial genome (mtDNA). However, the genetic landscape of mtDNA in the Chinese population has not been fully examined. Here, we described the genetic landscape of mtDNA using WGS data from Chinese individuals (n = 3241). We identified 3892 mtDNA variants, of which 3349 (86%) were rare variants. Interestingly, we observed a trend toward extreme heterogeneity of mtDNA variants. Our study observed a distinct purifying selection on mtDNA, which inhibits the accumulation of harmful heteroplasmies at the individual level: (1) mitochondrial dN/dS ratios were much <1; (2) the dN/dS ratio of heteroplasmies was higher than homoplasmies; (3) heteroplasmies had more indels and predicted deleterious variants than homoplasmies. Furthermore, we found that haplogroup M (20.27%) and D (20.15%) had the highest frequencies in the Chinese population, followed by B (18.51%) and F (16.45%). The number of variants per individual differed across haplogroup groups, with a higher number of homoplasmies for the M lineage. Meanwhile, mtDNA copy number was negatively correlated with age but positively correlated with the female sex. Finally, we developed an mtDNA variation database of Chinese populations called MTCards (http://genemed.tech/mtcards/) to facilitate the query of mtDNA variants in this study. In summary, these findings contribute to different aspects of understanding mtDNA, providing a better understanding of the genetic basis of mitochondrial-related diseases.

GGC expansions in NOTCH2NLC contribute to Parkinson disease and dopaminergic neuron degeneration.

BACKGROUND AND PURPOSE: The role of GGC repeat expansions within NOTCH2NLC in Parkinson's disease (PD) and the substantia nigra (SN) dopaminergic neuron remains unclear. Here, we profile the NOTCH2NLC GGC repeat expansions in a large cohort of patients with PD. We also investigate the role of GGC repeat expansions within NOTCH2NLC in the dopaminergic neurodegeneration of SN. METHODS: A total of 2,522 patients diagnosed with PD and 1,085 health controls were analyzed for the repeat expansions of NOTCH2NLC by repeat-primed PCR and GC-rich PCR assay. Furthermore, the effects of GGC repeat expansions in NOTCH2NLC on dopaminergic neurons were investigated by using recombinant adeno-associated virus (AAV)-mediated overexpression of NOTCH2NLC with 98 GGC repeats in the SN of mice by stereotactic injection. RESULTS: Four PD pedigrees (4/333, 1.2%) and three sporadic PD patients (3/2189, 0.14%) were identified with pathogenic GGC repeat expansions (larger than 60 GGC repeats) in the NOTCH2NLC gene, while eight PD patients and one healthy control were identified with intermediate GGC repeat expansions ranging from 41 to 60 repeats. No significant difference was observed in the distribution of intermediate NOTCH2NLC GGC repeat expansions between PD cases and controls (Fisher's exact test p-value = 0.29). Skin biopsy showed P62-positive intranuclear NOTCH2NLC-polyGlycine (polyG) inclusions in the skin nerve fibers of patient. Expanded GGC repeats in NOTCH2NLC produced widespread intranuclear and perinuclear polyG inclusions, which led to a severe loss of dopaminergic neurons in the SN. Consistently, polyG inclusions were presented in the SN of EIIa-NOTCH2NLC-(GGC)98 transgenic mice and also led to dopaminergic neuron loss in the SN. CONCLUSIONS: Overall, our findings provide strong evidence that GGC repeat expansions within NOTCH2NLC contribute to the pathogenesis of PD and cause degeneration of nigral dopaminergic neurons.

Association of rare PPARGC1A variants with Parkinson's disease risk.

BACKGROUND: Recent researches on Parkinson's disease (PD) pathogenesis discovered the correlation between PD and peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α) dysfunction and reduction of PPARGC1A gene expression. Hence, we detected PPARGC1A rare variants to clarify their effect on PD risk in a large population of PD patients in mainland China. METHODS: We applied whole-exome sequencing (WES) to 1917 patients with early-onset or familial PD and 1652 controls (WES cohort), and whole-genome sequencing (WGS) to 1962 patients with sporadic late-onset PD and 1279 controls (WGS cohort). To identify PPARGC1A rare variants, we used burden analysis to assess the relationship between PPARGC1A rare variants and PD susceptibility. RESULTS: 30 rare missense variants in the cohort WES and 21 missense variants in the cohort WGS have been detected in the study and PPARGC1A missense variants are significantly associated with early-onset and familial PD susceptibility in our study (P = 0.012), which supports evidence that PPARGC1A rare variants are involved in the onset of early-onset and familial PD. CONCLUSIONS: The study suggested that PPARGC1A rare variants may contribute to the risk of early-onset and familial PD.

The Chinese Parkinson's Disease Registry (CPDR): Study Design and Baseline Patient Characteristics.

BACKGROUND: There is a lack of large multicenter Parkinson's disease (PD) cohort studies and limited data on the natural history of PD in China. OBJECTIVES: The objective of this study was to launch the Chinese Parkinson's Disease Registry (CPDR) and to report its protocol, cross-sectional baseline data, and prospects for a comprehensive observational, longitudinal, multicenter study. METHODS: The CPDR recruited PD patients from 19 clinical sites across China between January 2018 and December 2020. Clinical data were collected prospectively using at least 17 core assessment scales. Patients were followed up for clinical outcomes through face-to-face interviews biennially. RESULTS: We launched the CPDR in China based on the Parkinson's Disease & Movement Disorders Multicenter Database and Collaborative Network (PD-MDCNC). A total of 3148 PD patients were enrolled comprising 1623 men (51.6%) and 1525 women (48.4%). The proportions of early-onset PD (EOPD, age at onset ≤50 years) and late-onset PD (LOPD) were 897 (28.5%) and 2251 (71.5%), respectively. Stratification by age at onset showed that EOPD manifested milder motor and nonmotor phenotypes and was related to increased probability of dyskinesia. Comparison across genders suggested a slightly older average age at PD onset, milder motor symptoms, and a higher rate of developing levodopa-induced dyskinesias in women. CONCLUSIONS: The CPDR is one of the largest multicenter, observational, longitudinal, and natural history studies of PD in China. It offers an opportunity to expand the understanding of clinical features, genetic, imaging, and biological markers of PD progression. © 2022 International Parkinson and Movement Disorder Society.

The role of genetics in Parkinson's disease: a large cohort study in Chinese mainland population.

This study aimed to determine the mutational spectrum of familial Parkinson's disease and sporadic early-onset Parkinson's disease (sEOPD) in a mainland Chinese population and the clinical features of mutation carriers. We performed multiplex ligation-dependent probe amplification assays and whole-exome sequencing for 1676 unrelated patients with Parkinson's disease in a mainland Chinese population, including 192 probands from families with autosomal-recessive Parkinson's disease, 242 probands from families with autosomal-dominant Parkinson's disease, and 1242 sEOPD patients (age at onset ≤ 50). According to standards and guidelines from the American College of Medical Genetics and Genomics, pathogenic/likely pathogenic variants in 23 known Parkinson's disease-associated genes occurred more frequently in the autosomal-recessive Parkinson's disease cohort (65 of 192, 33.85%) than in the autosomal-dominant Parkinson's disease cohort (10 of 242, 4.13%) and the sEOPD cohort (57 of 1242, 4.59%), which leads to an overall molecular diagnostic yield of 7.88% (132 of 1676). We found that PRKN was the most frequently mutated gene (n = 83, 4.95%) and present the first evidence of an SNCA duplication and LRRK2 p.N1437D variant in mainland China. In addition, several novel pathogenic/likely pathogenic variants including LRRK2 (p.V1447M and p.Y1645S), ATP13A2 (p.R735X and p.A819D), FBXO7 (p.G67E), LRP10 (c.322dupC/p.G109Rfs*51) and TMEM230 (c.429delT/p.P144Qfs*2) were identified in our cohort. Furthermore, the age at onset of the 132 probands with genetic diagnoses (median, 31.5 years) was about 14.5 years earlier than that of patients without molecular diagnoses (i.e. non-carriers, median 46.0 years). Specifically, the age at onset of Parkinson's disease patients with pathogenic/likely pathogenic variants in ATP13A2, PLA2G6, PRKN, or PINK1 was significantly lower than that of non-carriers, while the age at onset of carriers with other gene pathogenic/likely pathogenic variants was similar to that of non-carriers. The clinical spectrum of Parkinson's disease-associated gene carriers in this mainland Chinese population was similar to that of other populations. We also detected 61 probands with GBA possibly pathogenic variants (3.64%) and 59 probands with GBA p.L444P (3.52%). These results shed insight into the genetic spectrum and clinical manifestations of Parkinson's disease in mainland China and expand the existing repertoire of pathogenic or likely pathogenic variants involved in known Parkinson's disease-associated genes. Our data highlight the importance of genetic testing in Parkinson's disease patients with age at onset < 40 years, especially in those from families with a recessive inheritance pattern, who may benefit from early diagnosis and treatment.

Association of HIF1A and Parkinson's disease in a Han Chinese population demonstrated by molecular inversion probe analysis.

Parkinson's disease (PD) is a common neurodegenerative disorder with multiple factors contributing to disease pathogenesis. Previous studies implicated the involvement of the transcription factor hypoxia inducible factor 1 alpha (HIF1A) in PD through its transcriptional regulation of PD-associated genes. This study uses molecular inversion probes (MIPs) followed by high-throughput sequencing for the genetic analysis of HIF1A in a large cohort including 1692 ethnic Han Chinese PD patients and 1419 neurologically normal control subjects matched for age, gender, and ethnicity. Common HIF1A variant rs11549465 was found to be associated with increased late-onset PD (LOPD) risk (OR (95%CI) = 1.531(1.068-2.194), P = 0.03828 for trend test, P = 0.03948 for analyses using the allelic model and P = 0.04196 for logistic regression analyses (sex + age as covariates)). Though the gene-based variants burden test is negative, seven rare non-synonymous, predicted-pathogenic point variants were identified. In conclusion, our study further indicates that HIF1A plays a role in PD pathogenesis.

Genetic analysis of transcription factors in dopaminergic neuronal development in Parkinson's disease.

BACKGROUND: Genetic variants of dopaminergic transcription factor-encoding genes are suggested to be Parkinson's disease (PD) risk factors; however, no comprehensive analyses of these genes in patients with PD have been undertaken. Therefore, we aimed to genetically analyze 16 dopaminergic transcription factor genes in Chinese patients with PD. METHODS: Whole-exome sequencing (WES) was performed using a Chinese cohort comprising 1917 unrelated patients with familial or sporadic early-onset PD and 1652 controls. Additionally, whole-genome sequencing (WGS) was performed using another Chinese cohort comprising 1962 unrelated patients with sporadic late-onset PD and 1279 controls. RESULTS: We detected 308 rare and 208 rare protein-altering variants in the WES and WGS cohorts, respectively. Gene-based association analyses of rare variants suggested that MSX1 is enriched in sporadic late-onset PD. However, the significance did not pass the Bonferroni correction. Meanwhile, 72 and 1730 common variants were found in the WES and WGS cohorts, respectively. Unfortunately, single-variant logistic association analyses did not identify significant associations between common variants and PD. CONCLUSIONS: Variants of 16 typical dopaminergic transcription factors might not be major genetic risk factors for PD in Chinese patients. However, we highlight the complexity of PD and the need for extensive research elucidating its etiology.

Tremor-associated short tandem repeat intermediate and pathogenic expansions in familial essential tremor.

There is an obvious clinical-pathological overlap between essential tremor and some known tremor-associated short tandem repeat expansion disorders. The aim is to analyse whether these short tandem repeat genes, including ATXN1, ATXN2, ATXN3, CACNA1A, ATXN7, ATXN8OS, ATXN10, PPP2R2B, TBP, BEAN1, NOP56, DAB1, ATN1, SADM12 and FMR1, are associated with familial essential tremor patients. Genetic analysis of repeat sizes in tremor-associated short tandem repeat expansions was performed in a large cohort of 515 familial essential tremor probands and 300 controls. The demographic and clinical features among carriers of pathogenic expansions, intermediate repeats and non-carriers were compared. A total of 18 out of 515 (18/515, 3.7%) patients were found to have repeats expansions, including 12 cases (12/515, 2.5%) with intermediate repeat expansions (one ATXN1, eight TBP, two FMR1, one ATN1), and six cases (6/515, 1.2%) with pathogenic expansions (one ATXN1, one ATXN2, one ATXN8OS, one PPP2R2B, one FMR1, one SAMD12). There were no statistically significant differences in intermediate repeats compared to healthy controls. Furthermore, there were no significant differences in demographics and clinical features among individuals with pathogenic expansions, intermediate repeat expansions carriers and non-carriers. Our study indicates that the intermediate repeat expansion in tremor-associated short tandem repeat expansions does not pose an increased risk for essential tremor, and rare pathogenic expansion carriers have been found in the familial essential tremor cohort. The diagnosis of essential tremor based solely on clinical symptoms remains a challenge in distinguishing it from known short tandem repeat expansions diseases with overlapping clinical-pathological features.

Comprehensive variant analysis of phospholipase A2 superfamily genes in large Chinese Parkinson' s disease cohorts.

To clarify the genetic role of phospholipase A2 (PLA2) genes in Parkinson's disease (PD), we performed a genetic association study in large Chinese population cohorts using next-generation sequencing. In this study, we analyzed both rare and common variants of 38 phospholipase A2 genes in two large cohorts. We detected 1558 and 1115 rare variants in these two cohorts, respectively. In both cohorts, we observed suggestive associations between specific subgroups and the risk of PD. At the single-gene level, several genes (PLA2G2D, PLA2G12A, PLA2G12B, PLA2G4F, PNPLA1, PNPLA3, PNPLA7, PLA2G7, PLA2G15, PLAAT5, and ABHD12) are suggestively associated with PD. Meanwhile, 364 and 2261 common variants were identified in two cohorts, respectively. Our study has expanded the genetic spectrum of the PLA2 family genes and suggested potential pathogenetic roles of PLA2 superfamily in PD.

Screen-printed highly stretchable and stable flexible electrodes with a negative Poisson's ratio structure for supercapacitors.

Flexible power sources are crucial to developing flexible electronic systems; nonetheless, the current poor stretchability and stability of flexible power sources hinder their application in such devices. Accordingly, the stretchability and fatigue stability of flexible power sources are crucial for the practical application of flexible electronic systems. In this work, a flexible electrode with an arc-shaped star concave negative Poisson's ratio (NPR) structure is fabricated through the screen printing process. Using the combination of finite element analysis (FEA) and tensile tests, it is proven that the arc-shaped star concave NPR electrode can effectively reduce the maximum tensile stress and increase the maximum elongation (maximum elongation 140%). Furthermore, the flexible electrodes prepared in this study are assembled into all-solid-state symmetric supercapacitors (SSCs), and their electrochemical properties are tested. The SSC prepared in this study has a high areal capacitance of 243.1 mF cm-2. It retains 89.25% of its initial capacity after 5000 times of folding and can maintain a stable output even in extreme deformation, which indicates that the SSC prepared in this study has excellent stability. The SSC with the advantages mentioned above obtained in this study is expected to provide new opportunities to develop flexible electronic systems.

Evaluating the association between DNM1L variants and Parkinson's disease in the Chinese population.

Introduction: Parkinson's disease (PD) is a progressive movement disorder caused by a loss of dopaminergic neurons. Previous studies have highlighted the importance of mitochondria dynamics in the pathogenesis of PD. Dynamin-1-like (DNM1L) is a gene that encodes dynamin-related protein 1 (DRP1), a GTPase essential for proper mitochondria fission. In the present study, we evaluated the relationship between DNM1L variants and PD in the Chinese population. Methods: A total of 3,879 patients with PD and 2,931 healthy controls were recruited and burden genetic analysis combined with high-throughput sequencing was applied. Results: We identified 23 rare variants in the coding region of DNM1L, while no difference in variant burden was shown between the cases and controls. We also identified 201 common variants in the coding and flanking regions and found two significant SNPs, namely, rs10844308 and rs143794289 [odds ratio (OR) = 1.220 and 0.718, p = 0.025 and 0.036, respectively]. We also performed a meta-analysis to correlate the two SNPs with PD risk. However, none of the common variants was significant using logistic regression. Conclusion: Despite the critical role of DRP1, our study did not support the relationship between DNM1L variants and PD risk in the Chinese population.

Genetic analysis of dystonia-related genes in Parkinson's disease.

Objective: Parkinson's disease (PD) and dystonia are two closely related movement disorders with overlaps in clinical phenotype. Variants in several dystonia-related genes were demonstrated to be associated with PD; however, genetic evidence for the involvement of dystonia-related genes in PD has not been fully studied. Here, we comprehensively investigated the association between rare variants in dystonia-related genes and PD in a large Chinese cohort. Methods: We comprehensively analyzed the rare variants of 47 known dystonia-related genes by mining the whole-exome sequencing (WES) and whole-genome sequencing (WGS) data from 3,959 PD patients and 2,931 healthy controls. We initially identified potentially pathogenic variants of dystonia-related genes in patients with PD based on different inheritance models. Sequence kernel association tests were conducted in the next step to detect the association between the burden of rare variants and the risk for PD. Results: We found that five patients with PD carried potentially pathogenic biallelic variants in recessive dystonia-related genes including COL6A3 and TH. Additionally, we identified 180 deleterious variants in dominant dystonia-related genes based on computational pathogenicity predictions and four of which were considered as potentially pathogenic variants (p.W591X and p.G820S in ANO3, p.R678H in ADCY5, and p.R458Q in SLC2A1). A gene-based burden analysis revealed the increased burden of variant subgroups of TH, SQSTM1, THAP1, and ADCY5 in sporadic early-onset PD, whereas COL6A3 was associated with sporadic late-onset PD. However, none of them reached statistical significance after the Bonferroni correction. Conclusion: Our findings indicated that rare variants in several dystonia-related genes are suggestively associated with PD, and taken together, the role of COL6A3 and TH genes in PD is highlighted.

Characteristics of fatigue in Parkinson's disease: A longitudinal cohort study.

Objective: To assess the prevalence, evolution, clinical characteristics, correlates and predictors of fatigue as well as to investigate the influence of comorbid fatigue on the longitudinal changes in motor and non-motor symptoms over a 2-year longitudinal follow-up period in a large cohort of patients with Parkinson's disease (PD). Materials and methods: A total of 2,100 PD patients were enrolled from the Parkinson's Disease & Movement Disorders Multicenter Database and Collaborative Network in China (PD-MDCNC), and their motor and non-motor symptoms were assessed biennially using comprehensive scales, including the 16-item Parkinson Fatigue Scale (PFS-16). Each PD patient was categorized as PD with or without fatigue on the basis of a cut-off mean PFS-16 score of 3.3. Results: The prevalence of fatigue in our cohort was 36.8%. Compared to PD patients without fatigue, PD patients with fatigue were more likely to be older, have a longer disease duration, and higher baseline levodopa equivalent daily dose (all p < 0.05). Moreover, PD patients with fatigue showed more severe motor and non-motor phenotypes than those without fatigue. Overall, high total Unified Parkinson's Disease Rating Scale (UPDRS) score (odds ratio [OR] = 1.016, 95% confidence interval [CI]: 1.009-1.024), Non-Motor Symptoms Scale score (OR = 1.022, 95% CI: 1.015-1.029), postural instability and gait difficulty (PIGD) subtype (OR = 1.586, 95% CI: 1.211-2.079), presence of excessive daytime sleepiness (EDS; OR = 1.343, 95% CI: 1.083-1.666), and wearing-off (OR = 1.282, 95% CI: 1.023-1.607) were significantly associated with fatigue in PD patients (all p < 0.05). High total UPDRS score at baseline (OR = 1.014, 95% CI: 1.002-1.027, p = 0.028) increased the risk of developing fatigue during follow-up. Although significant, the odds ratios were low and confidence intervals were narrow. Analysis of disease progression showed significant group differences in motor and non-motor symptoms. In comparison with the never-fatigue group, the persistent-fatigue group showed significantly greater progression in motor, autonomic dysfunction, sleep, depression and cognitive symptoms (all p < 0.05). Conclusion: Increased disease severity, presence of the PIGD subtype, EDS, and wearing-off were associated with fatigue in PD patients. Significant subgroup-level differences were observed in the progression of motor and non-motor symptoms across different fatigue subgroups of PD patients.

Mutational spectrum and clinical features of GBA1 variants in a Chinese cohort with Parkinson's disease.

GBA1 variants are important risk factors for Parkinson's disease (PD). Most studies assessing GBA1-related PD risk have been performed in European-derived populations. Although the coding region of the GBA1 gene in the Chinese population has been analyzed, the sample sizes were not adequate. In this study, we aimed to investigate GBA1 variants in a large Chinese cohort of patients with PD and healthy control and explore the associated clinical characteristics. GBA1 variants in 4034 patients and 2931 control participants were investigated using whole-exome and whole-genome sequencing. The clinical features of patients were evaluated using several scales. Regression analysis, chi-square, and Fisher exact tests were used to analyze GBA1 variants and the clinical symptoms of different groups. We identified 104 variants, including 8 novel variants, expanding the spectrum of GBA1 variants. The frequency of GBA1 variants in patients with PD was 7.46%, higher than that in the control (1.81%) (P < 0.001, odds ratio [OR] = 4.38, 95% confidence interval [CI]: 3.26-5.89). Among patients, 176 (4.36%) had severe variants, 34 (0.84%) carried mild variants, three (0.07%) had risk variants, and 88 (2.18%) carried unknown variants. Our study, for the first time, found that p.G241R (P = 0.007, OR = 15.3, 95% CI: 1.25-261.1) and p.S310G (P = 0.005, OR = 4.86, 95% CI: 1.52-28.04) variants increased the risk of PD. Patients with GBA1 variants exhibited an earlier onset age and higher risk of probable rapid-eye-movement sleep behavior disorder, olfactory dysfunction, depression, and autonomic dysfunction than patients without GBA1 variants.

Evaluating the Genetic Role of Circadian Clock Genes in Parkinson's Disease.

Increasing evidence suggests that circadian dysfunction is related to Parkinson's disease (PD). However, the role of circadian clock genes in PD is still poorly understood. This study aimed to illustrate the association between genetic variants of circadian clock genes and PD in a large Chinese population cohort. Ten circadian clock genes were included in this study. Whole-exome sequencing (WES) was conducted in 1997 early-onset or familial PD patients and 1652 controls (WES cohort), and whole-genome sequencing (WGS) was conducted in 1962 sporadic late-onset PD patients and 1279 controls (WGS cohort). Analyses were completed using the optimized sequence kernel association test and regression analyses. In the burden analysis of the circadian clock gene set, we found suggestive significant associations between the circadian clock genes and PD in the WES cohort when considering missense, damaging missense (Dmis), and deleterious variants. Moreover, the burden analysis of single genes revealed suggestive significant associations between PD and the loss-of-function variants of the CRY1 gene, missense, Dmis, and deleterious variants of the PER1 gene, and Dmis and deleterious variants of the PER2 gene in the WES cohort. Rare variants in the WGS cohort and all common variants in the WGS and WES cohorts were unrelated to PD. Phenotypic analysis indicated that deleterious variants of the PER1 gene were associated with dyskinesia in the WES cohort. Our study provides evidence of a potential link between circadian clock genes and PD from a genetic perspective.

Evaluation of the role of FMR1 CGG repeat allele in Parkinson's disease from the Chinese population.

Objective: There is controversial evidence that FMR1 premutation or "gray zone" (GZ) allele (small CGG expansion, 45-54 repeats) was associated with Parkinson's disease (PD). We aimed to explore further the association between FMR1 CGG repeat expansions and PD in a large sample of Chinese origin. Methods: We included a cohort of 2,362 PD patients and 1,072 controls from the Parkinson's Disease and Movement Disorders Multicenter Database and Collaborative Network in China (PD-MDCNC) in this study and conducted repeat-primed polymerase chain reaction (RP-PCR) for the size of FMR1 CGG repeat expansions. Results: Two PD patients were detected with FMR1 premutation (61 and 56 repeats), and the other eleven PD patients were detected with the GZ allele of FMR1 CGG repeat expansions. Those thirteen PD patients responded well to levodopa and were diagnosed with clinically established PD. Specifically, one female PD patient with GZ allele was also found with premature ovarian failure. However, compared to healthy controls, we found no significant enrichment of GZ allele carriers in PD patients or other subgroups of PD cases, including the subgroups of female, male, early-onset, and late-onset PD patients. Furthermore, we did not find any correlation between the FMR1 gene CGG repeat sizes and age at onset of PD. Conclusion: It suggested that FMR1 premutation was related to PD, but the GZ allele of FMR1 CGG repeat expansions was not significantly enriched in PD cases of Chinese origin. Further larger multiple ethnic studies are needed to determine further the role of the FMR1 GZ allele in PD.

Genome-wide association study using whole-genome sequencing identifies risk loci for Parkinson's disease in Chinese population.

Genome-wide association studies (GWASs) have identified numerous susceptibility loci for Parkinson's disease (PD), but its genetic architecture remains underexplored in populations of non-European ancestry. To identify genetic variants associated with PD in the Chinese population, we performed a GWAS using whole-genome sequencing (WGS) in 1,972 cases and 2,478 controls, and a replication study in a total of 8209 cases and 9454 controls. We identified one new risk variant rs61204179 (Pcombined = 1.47 × 10-9) with low allele frequency, four previously reported risk variants (NUCKS1/RAB29-rs11557080, SNCA-rs356182, FYN-rs997368, and VPS13C-rs2251086), as well as three risk variants in LRRK2 coding region (A419V, R1628P, and G2385R) with genome-wide significance (P < 5 × 10-8) for PD in Chinese population. Moreover, of the reported genome-wide significant risk variants found mostly in European ancestry populations, the correlation coefficient (rb) of effect size accounting for sampling errors was 0.91 between datasets and 63.6% attained P < 0.05 in Chinese population. Accordingly, we estimated a heritability of 0.14-0.18 for PD, and a moderate genetic correlation between European ancestry and Chinese populations (rg = 0.47, se = 0.21). Polygenic risk score (PRS) analysis revealed that individuals with PRS values in the highest quartile had a 3.9-fold higher risk of developing PD than the lowest quartile. In conclusion, the present GWAS identified PD-associated variants in Chinese population, as well as genetic factors shared among distant populations. Our findings shed light on the genetic homogeneity and heterogeneity of PD in different ethnic groups and suggested WGS might continue to improve our understanding of the genetic architecture of PD.