Embracing Monogenic Parkinson's Disease: The MJFF Global Genetic PD Cohort

in Movement Disorders (2023), 38(2), 286--303

BACKGROUND: As gene-targeted therapies are increasingly being developed for Parkinson's disease (PD), identifying and characterizing carriers of specific genetic pathogenic variants is imperative. Only a ... [more ▼]

BACKGROUND: As gene-targeted therapies are increasingly being developed for Parkinson's disease (PD), identifying and characterizing carriers of specific genetic pathogenic variants is imperative. Only a small fraction of the estimated number of subjects with monogenic PD worldwide are currently represented in the literature and availability of clinical data and clinical trial-ready cohorts is limited. OBJECTIVE: The objectives are to (1) establish an international cohort of affected and unaffected individuals with PD-linked variants; (2) provide harmonized and quality-controlled clinical characterization data for each included individual; and (3) further promote collaboration of researchers in the field of monogenic PD. METHODS: We conducted a worldwide, systematic online survey to collect individual-level data on individuals with PD-linked variants in SNCA, LRRK2 VPS35, PRKN, PINK1, DJ-1, as well as selected pathogenic and risk variants in GBA and corresponding demographic, clinical, and genetic data. All registered cases underwent thorough quality checks, and pathogenicity scoring of the variants and genotype-phenotype relationships were analyzed. RESULTS: We collected 3888 variant carriers for our analyses, reported by 92 centers (42 countries) worldwide. Of the included individuals 3185 had a diagnosis of PD (ie, 1306 LRRK2, 115 SNCA, 23 VPS35 429 PRKN, 75 PINK1, 13 DJ-1, and 1224 GBA) and 703 were unaffected (ie, 328 LRRK2, 32 SNCA, 3 VPS35, 1 PRKN, 1 PINK1, and 338 GBA). In total, we identified 269 different pathogenic variants; 1322 individuals in our cohort (34\%) were indicated as not previously published. CONCLUSIONS: Within the MJFF Global Genetic PD Study Group, we (1) established the largest international cohort of affected and unaffected individuals carrying PD-linked variants; (2) provide harmonized and quality-controlled clinical and genetic data for each included individual; (3) promote collaboration in the field of genetic PD with a view toward clinical and genetic stratification of patients for gene-targeted clinical trials. 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society. [less ▲]

Genome-wide Association and Meta-analysis of Age-at-Onset in Parkinson Disease: Evidence From COURAGE-PD Consortium 10.1212/WNL.0000000000200699

in Neurology (2022)

Background and Objectives: Considerable heterogeneity exists in the literature concerning genetic determinants of the age of onset (AAO) of Parkinson\textquoterights disease (PD), which could be ... [more ▼]

Background and Objectives: Considerable heterogeneity exists in the literature concerning genetic determinants of the age of onset (AAO) of Parkinson\textquoterights disease (PD), which could be attributed to lack of well-powered replication cohorts. The previous largest GWAS identified SNCA and TMEM175 loci on chromosome (Chr) 4 with a significant influence on AAO of PD, these have not been independently replicated. The present study aims to conduct a meta-analysis of GWAS of PD AAO and validate previously observed findings in worldwide populations.Methods: A meta-analysis was performed on PD AAO GWAS of 30 populations of predominantly European ancestry from the Comprehensive Unbiased Risk Factor Assessment for Genetics and Environment in Parkinson\textquoterights Disease (COURAGE-PD) consortium. This was followed up by combining our study with the largest publicly available European ancestry dataset compiled by the International Parkinson disease Genomics Consortium (IPDGC).Results: The COURAGE-PD included a cohort of 8,535 patients with PD (91.9\%: Europeans, 9.1\%: East-Asians). The average AAO in the COURAGE-PD dataset was 58.9 years (SD=11.6), with an under-representation of females (40.2\%). The heritability estimate for AAO in COURAGE-PD was 0.083 (SE=0.057). None of the loci reached genome-wide significance (P\<5x10-8). Nevertheless, the COURAGE-PD dataset confirmed the role of the previously published TMEM175 variant as genetic determinant of AAO of PD with Bonferroni-corrected nominal levels of significance (P\<0.025): (rs34311866:β(SE)COURAGE=0.477(0.203), PCOURAGE=0.0185). The subsequent meta-analysis of COURAGE-PD and IPDGC datasets (Ntotal=25,950) led to the identification of two genome-wide significant association signals on Chr 4, including the previously reported SNCA locus (rs983361:β(SE)COURAGE+IPDGC=0.720(0.122), PCOURAGE+IPDGC=3.13x10-9) and a novel BST1 locus (rs4698412:β(SE)COURAGE+IPDGC=-0.526(0.096), PCOURAGE+IPDGC=4.41x10-8).Discussion: Our study further refines the genetic architecture of Chr 4 underlying the AAO of the PD phenotype through the identification of BST1 as a novel AAO PD locus. These findings open a new direction for the development of treatments to delay the onset of PD. [less ▲]

Effects of Subthalamic and Nigral Stimulation on Gait Kinematics in Parkinson's Disease.

in Frontiers in Neurology (2017), 8

Conventional subthalamic deep brain stimulation for Parkinson's disease (PD) presumably modulates the spatial component of gait. However, temporal dysregulation of gait is one of the factors that is ... [more ▼]

Conventional subthalamic deep brain stimulation for Parkinson's disease (PD) presumably modulates the spatial component of gait. However, temporal dysregulation of gait is one of the factors that is tightly associated with freezing of gait (FOG). Temporal locomotor integration may be modulated differentially at distinct levels of the basal ganglia. Owing to its specific descending brainstem projections, stimulation of the substantia nigra pars reticulata (SNr) area might modulate spatial and temporal parameters of gait differentially compared to standard subthalamic nucleus (STN) stimulation. Here, we aimed to characterize the differential effect of STN or SNr stimulation on kinematic gait parameters. We analyzed biomechanical parameters during unconstrained over ground walking in 12 PD patients with subthalamic deep brain stimulation and FOG. Patients performed walking in three therapeutic conditions: (i) Off stimulation, (ii) STN stimulation (alone), and (iii) SNr stimulation (alone). SNr stimulation was achieved by stimulating the most caudal contact of the electrode. We recorded gait using three sensors (each containing a tri-axial accelerometer, gyroscope, and magnetometer) attached on both left and right ankle, and to the lumbar spine. STN stimulation improved both the spatial features (stride length, stride length variability) and the temporal parameters of gait. SNr stimulation improved temporal parameters of gait (swing time asymmetry). Correlation analysis suggested that patients with more medial localization of the SNr contact associated with a stronger regularization of gait. These results suggest that SNr stimulation might support temporal regularization of gait integration. [less ▲]