Lara Mariah Lange

Introduction: GCH1 has been implicated in Parkinson's disease (PD), but its risks variants and associations are not well defined. Objectives: Our goal was to investigate the clinical relevance and PD risk associated with the GCH1 p.Ser80Asn variant. Methods: We first identified a segregating GCH1 p.Ser80Asn variant in a Malaysian Chinese PD family via whole genome sequencing (WGS). We assessed its risk association using multi‐ancestry WGS data from the Global Parkinson's Genetics Program (GP2) (n = 22,372 _PD vs. n = 8,826 _Controls ) and meta‐analysis of East Asian (EAS) cohorts (n = 4,712 _PD vs. 38,733 _Controls ). Haplotype analyses were performed and clinico‐demographic details of affected variant carriers were collated. Results: The GCH1 p.Ser80Asn variant was enriched in GP2 EAS PD populations (n = 9/2,757; 0.33%), but not detected in other ancestries. Meta‐analysis revealed increased PD risk in EAS populations (odds ratio = 5.1; 95% confidence intervals [CI] = 2.3–10.7; P = 2.89 × 10 ⁻⁵ ). A shared haplotype (~330 kbp) was identified among variant carriers. Affected carriers (mean age at onset: 56.3 ± 12.5 years) had additional occurrence of dystonia, whereas dementia was rare. Conclusions: The GCH1 p.Ser80Asn variant is a rare, EAS‐enriched risk variant for PD. © 2026 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society. © 2026 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Background Scalable models for Parkinson's disease (PD) genetics in underrepresented populations are needed, as most studies have focused on individuals of European-ancestry, limiting generalisability across ancestral and environmental contexts. Kyrgyzstan has been largely absent from global PD research. Using Kyrgyzstan as a case study, we aimed to develop and evaluate a scalable PD genetics model integrating research and local capacity building. Methods We implemented a stepwise capacity-building framework within a multi-site prospective PD genetics cohort that included participants with PD and controls, with longitudinal follow-up. The framework integrated community engagement, workforce development, specialist clinical services, data governance, clinical phenotyping, biobanking, and genetic data generation. Participants were recruited through a university-affiliated movement disorders clinic and mobile outreach clinics, using a secure electronic data-capture system and Global Parkinson's Genetics Program (GP2)-aligned standards. Feasibility endpoints included recruitment, participation, assessment completeness, and genetic quality-control metrics. Findings Within 20 months, specialist clinical services and a PD registry with biobanking and secure data infrastructure were established, and 1240 participants were enrolled, representing multiple Central Asian ethnicities, including Kyrgyz, Uzbek, Uyghur, Tatar, Kalmyk, and Dungan, and the country's rural-urban distribution. High participation coincided with community engagement and recruitment through mobile clinics and community outreach. Interpretation Embedding capacity building within active research enabled rapid development of neurogenetic and specialist clinical infrastructure in a resource-limited setting. This programme provides a potentially transferable model for equitable inclusion of underrepresented populations in PD genetics and related neurogenetic research in low- and middle-income countries. Funding This project was supported by the Global Parkinson's Genetics Program (GP2; https://gp2.org). GP2 is funded by the Aligning Science Across Parkinson's (ASAP) initiative and implemented by The Michael J. Fox Foundation for Parkinson's Research (MJFF).

Pathogenic variants in leucine-rich repeat kinase 2 ( LRRK2 ) ¹ are among the most frequent monogenic causes of Parkinson’s disease (PD) ² and act through a gain-of-function mechanism of increased kinase activity. LRRK2 -targeted therapies are in clinical development, but interpretation of the rapidly expanding catalogue of rare LRRK2 variants remains a barrier to translation. Here, we present functionally annotated data on >350 LRRK2 coding variants using a standardized cellular assay with Rab10 phosphorylation as a readout of kinase activity and integrated these data with curated genetic and clinical annotations from the Movement Disorders Society Genetic Mutation Database (MDSGene). Variants differed in activation magnitude, ranging from modest increases (e.g., p.G2019S) to strongly activating substitutions such as p.Y1699C or p.L1795F. Activating variants occurred across the full length of LRRK2, although the largest effects clustered within the ROC–COR regulatory hub, where structural analysis identified subdomains forming an allosteric scaffold controlling kinase output. All known/established pathogenic variants showed increased activity, whereas benign and likely benign variants remained within the wild-type range. Functional effect sizes correlated with pathway activation in patient-derived immune cells, altogether providing a framework for ACMG-based variant interpretation in which kinase activation can support PS3 functional evidence for reclassification of variants.

Expanded short tandem repeats contribute to a broad spectrum of neurodegenerative diseases, yet their roles in Parkinson’s disease (PD) and parkinsonism remain incompletely characterized, especially across diverse ancestries. We analyzed short-read whole-genome (WGS) and clinical exome sequencing (CES) data from 38,365 individuals (28,861 WGS; 9,504 CES), encompassing 23,242 patients with PD, 4,729 patients with atypical parkinsonism and 10,394 healthy controls from 11 genetic ancestries. To determine carrier frequencies and characterize repeat structures across diverse ancestries, we genotyped 12 established pathogenic loci where normal, intermediate, and pathogenic alleles can be reliably differentiated using short-read sequencing data. Additionally, we conducted threshold-based associations to determine the minimum threshold associated with increased PD risk in 15,995 individuals (8,591 PD, 7,404 controls) of European ancestry. Pathogenic repeat expansions were detected in 62 patients (56 PD and 6 atypical parkinsonism) and 5 controls across seven loci ( AR , ATXN1 , ATXN2 , ATXN3 , CACNA1A , HTT and THAP11 ), spanning seven ancestries. Among these, ATXN2 expansions were the most frequently observed in PD and were present in African, East Asian, European and Middle Eastern ancestries. Additionally, intermediate ATXN2 repeat expansions exhibited a strong, length-dependent association with PD risk in the European population, with individuals with ≥32 repeats having a more than four-fold increased risk (odds ratio 4.25, 95% confidence interval 1.80-12.05). Overall, >92% of expanded alleles harbor CAA interruptions within the CAG tract. Pathogenic expansions at other loci, such as ATXN3 and THAP11 , showed more ancestry-specific distributions. Clinically, individuals with pathogenic ATXN2 and ATXN3 expansions most often presented with typical PD features but frequently showed earlier disease onset and a strong family history of PD. This large-scale, multi-ancestry study comprehensively maps the genetic landscape of pathogenic and intermediate repeat expansions in PD. Our findings confirm a length- and structure-dependent risk association for ATXN2 with PD in the European population and highlight the pleiotropic effects of repeat expansions across the parkinsonian spectrum.

SORL1, the gene encoding the SORLA protein, has arisen as a potential therapeutic target for Alzheimer’s disease (AD). Studies suggest that restoring SORLA function or its trafficking pathways, particularly the SORLA–retromer recycling system, may offer a promising strategy to slow or halt AD progression. While both rare and common SORL1 variants have been associated with increased AD risk, recent evidence suggests a potential involvement of SORL1 in other neurodegenerative conditions. This study assessed the contribution of SORL1 genetic variation to the risk of AD, related dementias (RD), and Parkinson’s disease (PD) using data from six large-scale biobanks, comprising 15,043 AD, 9,943 RD, and 42,763 PD cases, along with 111,969 controls across 11 ancestries. We identified 53 potentially disease-related SORL1 variants (CADD score > 20, MAC ≥ 2, annotated as protein-altering or splicing, and with the mutated allele present only in cases), including 41 novel and 12 previously reported variants. Three were found across multiple ancestries. Overall, 13 variants were found in AD-related cohorts, 5 in RD cohorts, and 35 in PD cohorts. Association analysis identified 10 nominally significant variants associated with AD and 5 with PD. The replication of multiple SORL1 variants across neurodegenerative diseases and ancestrally diverse populations underscores its potential broad genetic contribution to neurodegeneration and reinforces its relevance across distinct clinical phenotypes. Burden analysis identified a nominal association of SORL1 variants in PD in the South Asian population (P = 0.048). A family-based analysis identified a rare predicted-damaging variant in two East Asian families (11:121478242:G:A, p.R176Q) and two variants in two families of European ancestry (11:121514222:A:C, p.N371T; 11:121545392:G:A, p.V672M) that show some evidence of segregation in PD families. Although these variants were slightly more frequent in unrelated PD cases vs. controls, none of them showed statistically significant enrichment in PD, likely due to their very low frequency. Overall, our results extend the understanding of SORL1 beyond AD, suggesting a broader role in neurodegeneration and emphasizing the need for diverse population studies when evaluating genetic risk.

Background: Large‐scale sequencing initiatives have generated extensive genomic resources essential for variant interpretation, yet their effective use often requires bioinformatics expertise. To support identification of Parkinson's disease (PD) risk and disease‐causing variants, we developed an open‐access, summary‐level genomic data browser. Methods: We performed uniform joint variant calling to harmonize whole‐genome sequencing (WGS) data from AMP‐PD Release 4, GP2 Data Releases, and additional controls from the Alzheimer's Disease Sequencing Project. Clinical‐exome sequencing (CES) data from GP2 Release 8 were also included. Results: The integrated dataset included 31,665 WGS and 9,559 CES samples, spanning 11 ancestries and over 300 million variants. Conclusions: The GP2 Genome Browser is a lightweight, flexible platform providing intuitive gene‐ and variant‐level summaries with ancestry‐stratified allele frequencies and functional annotations. It is open source and freely accessible at https://gp2.broadinstitute.org , enabling broad access to PD genomic data and supporting global research efforts. © 2026 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society. © 2026 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

In the Global Parkinson’s Genetics Program (GP2) we aim to advance precision medicine by integrating large-scale clinico-genetic data from diverse populations worldwide. We investigated potentially trial-eligible carriers of pathogenic and high-risk GBA1 and LRRK2 variants and conducted a global precision-medicine survey across GP2 sites. Among 65,509 individuals with Parkinson’s disease, we identified 9,019 (13.8%) potentially trial-eligible genetic variant carriers, including 6,789 GBA1 , 2,084 LRRK2 , and 146 dual GBA1-LRRK2 carriers. Individuals were distributed across multiple global regions, many of which currently lack active gene-targeted trials, highlighting a global disparity between relevant variant carriers and the availability of disease modifying treatment trials. GP2’s unified framework supports equitable recruitment for gene-targeted therapeutic studies and helps address critical gaps in Parkinson’s disease genetics and future therapeutic development.

SORL1, the gene encoding the SORLA protein, has arisen as a potential therapeutic target for Alzheimer’s disease (AD). Studies suggest that restoring SORLA function or its trafficking pathways, particularly the SORLA–retromer recycling system, may offer a promising strategy to slow or halt AD progression. While both rare and common SORL1 variants have been associated with increased AD risk, recent evidence suggests a potential involvement of SORL1 in other neurodegenerative conditions. This study assessed the contribution of SORL1 genetic variation to the risk of AD, related dementias (RD), and Parkinson’s disease (PD) using data from six large-scale biobanks, comprising 15,043 AD, 9,943 RD, and 42,763 PD cases, along with 111,969 controls across 11 ancestries. We identified 53 potentially disease-related SORL1 variants (CADD score > 20, MAC ≥ 2, annotated as protein-altering or splicing, and with the mutated allele present only in cases), including 41 novel and 12 previously reported variants. Three were found across multiple ancestries. Overall, 13 variants were found in AD-related cohorts, 5 in RD cohorts, and 35 in PD cohorts. Association analysis identified 10 nominally significant variants associated with AD and 5 with PD. The replication of multiple SORL1 variants across neurodegenerative diseases and ancestrally diverse populations underscores its potential broad genetic contribution to neurodegeneration and reinforces its relevance across distinct clinical phenotypes. Gene-based burden analysis did not reveal any significant cumulative effect of SORL1 variants in the populations tested. A family-based analysis identified a rare predicted-damaging variant in two East Asian families (11:121478242:G:A, p.R176Q) and two variants in two families of European ancestry (11:121514222:A:C, p.N371T; 11:121545392:G:A, p.V672M) that show some evidence of segregation in PD families. Although these variants were slightly more frequent in unrelated PD cases vs. controls, none of them showed statistically significant enrichment in PD, likely due to their very low frequency. Overall, our results extend the understanding of SORL1 beyond AD, suggesting a broader role in neurodegeneration and emphasizing the need for diverse population studies when evaluating genetic risk.

Motivation: Copy Number Variations (CNVs) play pivotal roles in complex disease etiology, often requiring large sample sizes to analyze disease associations. While genotyping arrays offer a cost-effective approach for CNV detection using Log R Ratio (LRR) and B Allele Frequency (BAF) signals, existing independent array-based callers suffer from high false positive rates and noise susceptibility, burdening manual validation. Results: We present CNV-Finder, a deep learning pipeline employing Long Short-Term Memory (LSTM) networks for large-scale CNV identification within user-defined genomic regions. Trained on expert-annotated samples from the Global Parkinson’s Genetics Program across four neurodegenerative disease-associated genes (PRKN, LINGO2, MAPT, SNCA), CNV-Finder integrates human feedback to iteratively improve performance. In benchmarking across 105 936 samples spanning 11 ancestries and nearly 150 cohorts, the model achieved 91% and 89% visual confirmation rates for PRKN deletions and duplications at high-confidence thresholds. In two validation cohorts, CNV-Finder nominated 83% fewer candidates than a popular Hidden Markov Model-based caller while maintaining higher confirmation rates. Validation through MLPA, short-read, and long-read sequencing demonstrated robust performance, generalizing to diverse signatures including homozygous deletions and SNCA triplications absent from training. Our findings highlight human expertise’s value in complex loci like 17q21.31. Availability and implementation: CNV-Finder is freely available at https://github.com/nvk23/CNV-Finder.