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The impact of LRRK2 variants on the risk of Parkinson's disease in Egyptians remains unknown. We examined 1210 Egyptians (611 PD patients and 599 controls) from 16 governorates across Egypt for 12 LRRK2 pathogenic variants. The p.Gly2019Ser was the only variant detected, with a prevalence of 4.1% in sporadic cases, 6.5% in familial cases, and 0.68% in controls. Among p.Gly2019Ser carriers, all were heterozygous bar one homozygous patient, and all shared the common haplotype 1. Demographics and UPDRS scores did not differ between carriers and non-carriers, with most patients being males and developed PD in their fifties. Young and Early-onset PD prevalence was 37.5% in carriers and 33% in non-carriers. Familial cases were 16.6% in carriers and 11.5% in non-carriers. This study affirms that like other Mediterranean populations, Egyptians with PD have a higher prevalence of the p.Gly2019Ser variant compared to the global average. LRRK2 inhibitors could be promising therapeutic options for further exploration in this population., (© 2024. The Author(s).)

Competing Interests: Declaration of interests We declare no competing interests.

Two of every three persons living with dementia reside in low- and middle-income countries (LMICs). The projected increase in global dementia rates is expected to affect LMICs disproportionately. However, the majority of global dementia care costs occur in high-income countries (HICs), with dementia research predominantly focusing on HICs. This imbalance necessitates LMIC-focused research to ensure that characterization of dementia accurately reflects the involvement and specificities of diverse populations. Development of effective preventive, diagnostic, and therapeutic approaches for dementia in LMICs requires targeted, personalized, and harmonized efforts. Our article represents timely discussions at the 2022 Symposium on Dementia and Brain Aging in LMICs that identified the foremost opportunities to advance dementia research, differential diagnosis, use of neuropsychometric tools, awareness, and treatment options. We highlight key topics discussed at the meeting and provide future recommendations to foster a more equitable landscape for dementia prevention, diagnosis, care, policy, and management in LMICs. HIGHLIGHTS: Two-thirds of persons with dementia live in LMICs, yet research and costs are skewed toward HICs. LMICs expect dementia prevalence to more than double, accompanied by socioeconomic disparities. The 2022 Symposium on Dementia in LMICs addressed advances in research, diagnosis, prevention, and policy. The Nairobi Declaration urges global action to enhance dementia outcomes in LMICs., (© 2024 The Authors. Alzheimer's & Dementia published by Wiley Periodicals LLC on behalf of Alzheimer's Association.)

Pathogenic variants in LRRK2 are one of the most common genetic risk factors for Parkinson's disease (PD). Recently, the lesser-known p.L1795F variant was proposed as a strong genetic risk factor for PD, however, further families are currently lacking in literature. A multicentre young onset and familial PD cohort (n = 220) from 9 movement disorder centres across Central Europe within the CEGEMOD consortium was screened for rare LRRK2 variants using whole exome sequencing data. We identified 4 PD cases with heterozygous p.L1795F variant. All 4 cases were characterised by akinetic-rigid PD phenotype with early onset of severe motor fluctuations, 2 receiving LCIG therapy and 2 implanted with STN DBS; all 4 cases showed unsatisfactory effect of advanced therapies on motor fluctuations. Our data also suggest that p.L1795F may represent the most common currently known pathogenic LRRK2 variant in Central Europe compared to the more studied p.G2019S, being present in 1.81% of PD cases within the Central European cohort and 3.23% of familial PD cases. Together with the ongoing clinical trials for LRRK2 inhibitors, this finding emphasises the urgent need for more ethnic diversity in PD genetic research., Competing Interests: Confiict of Interest The authors declare no confiicts of interest.

Background: Africans are underrepresented in Huntington's disease (HD) research. A European ancestor was postulated to have introduced the mutant Huntingtin (mHtt) gene to the continent; however, recent work has shown the existence of a unique Htt haplotype in South-Africa specific to indigenous Africans., Objective: We aimed to investigate the CAG trinucleotide repeats expansion in the Htt gene in a geographically diverse cohort of patients with chorea and unaffected controls from sub-Saharan Africa., Methods: We evaluated 99 participants: 43 patients with chorea, 21 asymptomatic first-degree relatives of subjects with chorea, and 35 healthy controls for the presence of the mHtt. Participants were recruited from 5 African countries. Additional data were collected from patients positive for the mHtt gene; these included demographics, the presence of psychiatric and (or) cognitive symptoms, family history, spoken languages, and ethnic origin. Additionally, their pedigrees were examined to estimate the number of people at risk of developing HD and to trace back the earliest account of the disease in each region., Results: HD cases were identified in all countries. Overall, 53.4% of patients with chorea were carriers for the mHTT; median tract size was 45 CAG repeats. Of the asymptomatic relatives, 28.6% (6/21) were carriers for the mHTT; median tract size was 40 CAG. No homozygous carries were identified. Median CAG tract size in controls was 17 CAG repeats. Men and women were equally affected by HD. All patients with HD-bar three who were juvenile onset of <21 years-were defined as adult onset (median age of onset was 40 years). HD transmission followed an autosomal dominant pattern in 84.2% (16/19) of HD families. In familial cases, maternal transmission was higher 52.6% (10/19) than paternal transmission 36.8% (7/19). The number of asymptomatic individuals at risk of developing HD was estimated at ten times more than the symptomatic patients. HD could be traced back to the early 1900s in most African sites. HD cases spread over seven ethnic groups belonging to two distinct linguistic lineages separated from each other approximately 54-16 kya ago: Nilo-Sahara and Niger-Congo., Conclusion: This is the first study examining HD in multiple sites in sub-Saharan Africa. We demonstrated that HD is found in multiple ethnic groups residing in five sub-Saharan African countries including the first genetically confirmed HD cases from Guinea and Kenya. The prevalence of HD in the African continent, its associated socio-economic impact, and genetic origins need further exploration and reappraisal., (© 2024 The Authors. Annals of Human Genetics published by University College London (UCL) and John Wiley & Sons Ltd.)

Background: Rapid eye movement (REM) sleep behavior disorder (RBD) is an early feature of Parkinson's disease (PD) and dementia with Lewy bodies (DLB). Damaging coding variants in Glucocerebrosidase (GBA1) are a genetic risk factor for RBD. Recently, a population-specific non-coding risk variant (rs3115534) was found to be associated with PD risk and earlier onset in individuals of African ancestry., Objectives: We aimed to investigate whether the GBA1 rs3115534 PD risk variant is associated with RBD in persons with PD., Methods: We studied 709 persons with PD and 776 neurologically healthy controls from Nigeria. All DNA samples were genotyped and imputed, and the GBA1 rs3115534 risk variant was extracted. The RBD screening questionnaire (RBDSQ) was used to assess symptoms of possible RBD., Results: RBD was present in 200 PD (28.2%) and 51 (6.6%) controls. We identified that the non-coding GBA1 rs3115534 risk variant is associated with possible RBD in individuals of Nigerian origin (β, 0.3640; standard error [SE], 0.103, P = 4.093e-04), as well as in all samples after adjusting for PD status (β, 0.2542; SE, 0.108; P = 0.019) suggesting that although non-coding, this variant may have the same downstream consequences as GBA1 coding variants., Conclusions: Our results indicate that the non-coding GBA1 rs3115534 risk variant is associated with an increasing number of RBD symptoms in persons with PD of Nigerian origin. Further research is needed to assess if this variant is also associated with polysomnography-defined RBD and with RBD symptoms in DLB. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society., (© 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.)

Introduction: Parkinson's disease (PD) is the most common motor neurodegenerative disease worldwide. Given the complexity of PD etiology and the different metabolic derangements correlated to the disease, metabolomics profiling of patients is a helpful tool to identify patho-mechanistic pathways for the disease development. Dopamine metabolism has been the target of several previous studies, of which some have reported lower phenylalanine and tyrosine levels in PD patients compared to controls. Methods: In this study, we have collected plasma from 27 PD patients, 18 reference controls, and 8 high-risk controls to perform a metabolomic study using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS). Results: Our findings revealed higher intensities of trans-cinnamate, a phenylalanine metabolite, in patients compared to reference controls. Thus, we hypothesize that phenylalanine metabolism has been shifted to produce trans-cinnamate via L-phenylalanine ammonia lyase (PAL), instead of producing tyrosine, a dopamine precursor, via phenylalanine hydroxylase (PAH). Discussion: Given that these metabolites are precursors to several other metabolic pathways, the intensities of many metabolites such as dopamine, norepinephrine, and 3-hydroxyanthranilic acid, which connects phenylalanine metabolism to that of tryptophan, have been altered. Consequently, and in respect to Metabolic Control Analysis (MCA) theory, the levels of tryptophan metabolites have also been altered. Some of these metabolites are tryptamine, melatonin, and nicotinamide. Thus, we assume that these alterations could contribute to the dopaminergic, adrenergic, and serotonergic neurodegeneration that happen in the disease., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Shebl, El-Jaafary, Saeed, Elkafrawy, El-Sayed, Shamma, Elnemr, Mekky, Mohamed, Kittaneh, El-Fawal, Rizig and Salama.)

Background: An understanding of the genetic mechanisms underlying diseases in ancestrally diverse populations is an important step towards development of targeted treatments. Research in African and African admixed populations can enable mapping of complex traits, because of their genetic diversity, extensive population substructure, and distinct linkage disequilibrium patterns. We aimed to do a comprehensive genome-wide assessment in African and African admixed individuals to better understand the genetic architecture of Parkinson's disease in these underserved populations., Methods: We performed a genome-wide association study (GWAS) in people of African and African admixed ancestry with and without Parkinson's disease. Individuals were included from several cohorts that were available as a part of the Global Parkinson's Genetics Program, the International Parkinson's Disease Genomics Consortium Africa, and 23andMe. A diagnosis of Parkinson's disease was confirmed clinically by a movement disorder specialist for every individual in each cohort, except for 23andMe, in which it was self-reported based on clinical diagnosis. We characterised ancestry-specific risk, differential haplotype structure and admixture, coding and structural genetic variation, and enzymatic activity., Findings: We included 197 918 individuals (1488 cases and 196 430 controls) in our genome-wide analysis. We identified a novel common risk factor for Parkinson's disease (overall meta-analysis odds ratio for risk of Parkinson's disease 1·58 [95% CI 1·37-1·80], p=2·397 × 10 -14 ) and age at onset at the GBA1 locus, rs3115534-G (age at onset β=-2·00 [SE=0·57], p=0·0005, for African ancestry; and β=-4·15 [0·58], p=0·015, for African admixed ancestry), which was rare in non-African or non-African admixed populations. Downstream short-read and long-read whole-genome sequencing analyses did not reveal any coding or structural variant underlying the GWAS signal. The identified signal seems to be associated with decreased glucocerebrosidase activity., Interpretation: Our study identified a novel genetic risk factor in GBA1 in people of African ancestry, which has not been seen in European populations, and it could be a major mechanistic basis of Parkinson's disease in African populations. This population-specific variant exerts substantial risk on Parkinson's disease as compared with common variation identified through GWAS and it was found to be present in 39% of the cases assessed in this study. This finding highlights the importance of understanding ancestry-specific genetic risk in complex diseases, a particularly crucial point as the Parkinson's disease field moves towards targeted treatments in clinical trials. The distinctive genetics of African populations highlights the need for equitable inclusion of ancestrally diverse groups in future trials, which will be a valuable step towards gaining insights into novel genetic determinants underlying the causes of Parkinson's disease. This finding opens new avenues towards RNA-based and other therapeutic strategies aimed at reducing lifetime risk of Parkinson's disease., Funding: The Global Parkinson's Genetics Program, which is funded by the Aligning Science Across Parkinson's initiative, and The Michael J Fox Foundation for Parkinson's Research., Competing Interests: Declaration of interests DV, HI, HLL, KSL, CXA, and MAN's participation in this project was part of a competitive contract awarded to Data Tecnica International by the US National Institutes of Health (NIH) to support open science research. MAN also currently serves on the scientific advisory board for Character Biosciences and Neuron 23. KH is employed by 23andMe and holds stock or stock options in 23andMe. AS, MBM, PAJ, CB, KD, MJK, JJK, and PWC are employed by the NIH. AS also declares funding for the present work from the Michael J Fox Foundation (MJFF) and Aligning Science Across Parkinson's (ASAP); royalties for a diagnostic for stroke (unrelated to the current work); honoraria for associate editorial work for the journals Movement Disorders and npj Parkinson's Disease; and travel support from the Chan Zuckerberg Initiative to attend annual investigators’ meeting, MJFF to attend Parkinson's Progression Marker Initiative annual meeting, and Weill Cornell to give grand rounds. The spouse of AS is an employee of GeneDx. OOk, IE, HI, JHK, and DV declare funding from the NIH (1ZIA AG000534-04). HI also declares honoraria from GP2 for a steering committee meeting and from MJFF for a data community meeting. DGS declares support for the present work from ASAP (for the BLAAC-PD study); research support from the NIH (P50 108675), the MJFF, the Parkinson Foundation of the National Capital Area, the American Parkinson Disease Association, AbbVie, and Genentech; book royalties from McGraw Hill; consulting fees from AbbVie, Curium Pharma, F Hoffman-La Roche, Appello Pharma, and Blue Rock Therapeutics; participation on a data safety monitoring board or advisory board for Sanofi-Aventis, Theravance, and Alnylam Pharmaceuticals; being Deputy Editor of the journal Movement Disorders; and being Chair of the Scientific Advisory Board of the American Parkinson Disease Association. DAH declares support for the present work from the NIH, the MJFF, the CHDI Foundation, Parkinson's Foundation, Lundbeck, Uniqure, and Neurocrine. TX declares research funding from the MJFF, the American Parkinson's Disease Association, and the NIH; and consulting fees from Parkinson's Foundation and CVS Caremark. HH and JH declare research funding by the Medical Research Council (UK), the Wellcome Trust, the MSA Trust, NIHR University College London Hospitals Biomedical Research Centre (NIHR-BRC), the MJFF, the Fidelity Trust, the Rosetrees Trust, the Guarantors of Brain, SOLVE-RD, and the Dolby Family Fund. HRM declares support from the MJFF related to this work; grants not related to this work from PSP Association, CBD Solutions, Drake Foundation, and Cure Parkinson's Trust; consulting fees from Roche, Amylyx, and Aprinoia; speaker's honoraria from Kyowa-Kirin, the British Medical Journal, and the Movement Disorders Society; travel support from the MJFF and the Movement Disorders Society; and being on the advisory board for Cure PSP Association, the Association of British Neurologists Movement Disorders special interest group, and the Association of British Neurologists Neurogenetics advisory group. HRM is a co-applicant on a patent application related to C9ORF72—Method for diagnosing a neurodegenerative disease (PCT/GB2012/052140). ES declares funding for the present work from the US National Human Genome Research Institute (NHGRI) Intramural Research Program; grants from ASAP and MJFF; and a cooperative research and development agreement with Roche. EAS declares funding for the present work from the MJFF; and travel support from the MJFF. MND declares funding for the present work from MJFF; grant support from ASAP; speaker's honoraria from the Parkinson's Foundation; and is a member of the Parkinson's Foundation Gulf Coast advisory board. Z-HF declares salary support from the MJFF. OOOj declares a study grant from the NIHR; honoraria for educational courses from the International Parkinson and Movement Disorder Society (IPMDS); travel support from P2 for an annual investigators’ meeting and from the IPMDS for congress attendance; and is a member of the executive committee of the IPMDS. NUO declares a study grant from the NIHR; travel support and honoraria for educational courses from the IPMDS; and being Chair of the IPMDS Africa Section. UA declares a study grant from the NIHR. RA declares grant support from the NIH (U01HG010273, U19AG074865), the UK Royal Society and the African Academy of Sciences Future Leaders—African Independent Research (FLR/R1/191813, FCG/R1/201034), and the Global Brain Health Institute, Alzheimer's Association, and Alzheimer's Society UK (GBHI ALZ UK-21- 24204). TF declares speaker's honoraria from Roche; travel support from the Alzheimer's Association; and is a member of the Alzheimer's Disease International medical and scientific advisory panel. CB declares support from ASAP. KD declares a Japan Society for the Promotion of Science Research Fellowship. JJK declares participation in the graduate school programme for Queen Mary University London (London, UK). PAJ declares participation in the graduate school programme for University College London (London, UK). MBM declares participation in a summer internship at Genentech/Roche (unrelated to the current work). All other authors declare no competing interests., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Introduction: The association between MAPT and PD risk may be subject to ethnic variability even within populations of similar geographical origin. Data on MAPT haplotype frequencies, and its association with PD risk in black Africans are lacking. We aimed to determine the frequencies of MAPT haplotypes and their role as risk factors for PD and age at onset in Nigerians., Methods: The haplotype and genotype frequencies of MAPT rs1052553 were analysed in 907 individuals with PD and 1022 age-matched healthy controls from the Nigeria Parkinson's Disease Research network cohort. Clinical data related to PD included age at study, age at onset (AAO), and disease duration., Results: The frequency of the H1 haplotype was 98.7% in PD, and 99.1% in controls (p = 0.19). The H2 haplotype was present in - 1.3% of PD and 0.9% of controls (p = 0.24). The most frequent MAPT genotype was H1H1 (PD - 97.5%, controls - 98.2%). The H1 haplotype was not associated with PD risk after accounting for gender and AAO (Odds ratio for H1/H1 vs H1/H2 and H2/H2: 0.68 (95% CI:0.39-1.28); p = 0.23)., Conclusions: Our findings support previous studies that report a low frequency of the MAPT H2 haplotype in black ancestry Africans but document its occurrence in Nigerians. The MAPT H1 haplotype was not associated with an increased risk or age at onset of PD in this cohort., Competing Interests: Declaration of competing interest R.A. is supported by the following grants: US NIH/NHGRI (U01HG010273) and the UK Royal Society/African Academy of Sciences (FLR/R1/191813). M.R. received funding from the University College London Grand challenges Small Grants (Award ID:177813 and the Michael J Fox Foundation Genetic Diversity in Parkinson's Disease 2019 (Grant ID:17483). H.H. is supported by the Michael J Fox Foundation Genetic Diversity in Parkinson's Disease (Grant ID: 17483). N.U.O. is supported by the Michael J Fox Foundation Genetic Diversity in Parkinson's Disease 2019 (Grant ID:17483) and the TETFund National Research Fund (NRF) 2019. S.B.-C., C.B. and A.S. are supported by the Intramural Research Program, National Institute on Aging, National Institutes of Health and US Department of Health and Human Services project ZO1 AG000949 and all these authors declare no non-financial competing interests. The remaining authors declare no competing interests., (Copyright © 2023. Published by Elsevier Ltd.)

Aims: Malignant polyps are examined to assess histological features which predict residual tumour in the unresected bowel and guide surgical decision-making. One of the most important of these features is resection margin involvement, although the best definition of margin involvement is unknown. In this study we aimed to investigate three different definitions and determine their impact on clinical outcomes., Methods and Results: One hundred and sixty-five malignant polyps removed endoscopically were identified and histological features correlated with either residual tumour in subsequent surgical resections or tumour recurrence following a period of clinical follow-up. Involvement of the polyp margin by cancer was defined in three different ways and outcomes compared. Tumour recurrence was associated with tumour grade, mucinous histology and resection margin involvement. All three definitions of margin involvement separated polyps into clinically significant categories; however, a margin ≤ 1 mm identified 73% of polyps as 'high-risk' compared with 59.1% when involvement was defined as tumour within the zone of coagulation artefact at the polyp base or 50% when tumour was present at the margin. All three 'low-risk' groups had a locoregional recurrence rate < 6.5%., Conclusions: Definitions of margin involvement for endoscopically removed malignant polyps in the colon and rectum vary between health-care systems, but a 1-mm clearance is widely used in Europe and North America. Our results suggest that a 1-mm margin is unnecessary and should be replaced by a definition based on tumour at the margin or within coagulation artefact at the polyp base., (© 2023 John Wiley & Sons Ltd.)

The relationship between APOE polymorphisms and Parkinson's disease (PD) in black Africans has not been previously investigated. We evaluated the association between APOE polymorphic variability and self-declared cognition in 1100 Nigerians with PD and 1097 age-matched healthy controls. Cognition in PD was assessed using the single item cognition question (item 1.1) of the MDS-UPDRS. APOE genotype and allele frequencies did not differ between PD and controls (p > 0.05). No allelic or genotypic association was observed between APOE and age at onset of PD. In PD, APOE ε4/ε4 conferred a two-fold risk of cognitive impairment compared to one or no ε4 (HR: 2.09 (95% CI: 1.13-3.89; p = 0.02)), while APOE ε2 was associated with modest protection against cognitive impairment (HR: 0.41 (95% CI 0.19-0.99, p = 0.02)). Of 773 PD with motor phenotype and APOE characterized, tremor-dominant (TD) phenotype predominated significantly in ε2 carriers (87/135, 64.4%) compared to 22.2% in persons with postural instability/gait difficulty (PIGD) (30/135) and 13.3% in indeterminate (ID) (18/135, 13.3%) (p = 0.037). Although the frequency of the TD phenotype was highest in homozygous ε2 carriers (85.7%), the distribution of motor phenotypes across the six genotypes did not differ significantly (p = 0.18). Altogether, our findings support previous studies in other ethnicities, implying a role for APOE ε4 and ε2 as risk and protective factors, respectively, for cognitive impairment in PD., (© 2022. The Author(s).)

Background: Human genetics research lacks diversity; over 80% of genome-wide association studies have been conducted on individuals of European ancestry. In addition to limiting insights regarding disease mechanisms, disproportionate representation can create disparities preventing equitable implementation of personalized medicine., Objective: This systematic review provides an overview of research involving Parkinson's disease (PD) genetics in underrepresented populations (URP) and sets a baseline to measure the future impact of current efforts in those populations., Methods: We searched PubMed and EMBASE until October 2021 using search strings for "PD," "genetics," the main "URP," and and the countries in Latin America, Caribbean, Africa, Asia, and Oceania (excluding Australia and New Zealand). Inclusion criteria were original studies, written in English, reporting genetic results on PD from non-European populations. Two levels of independent reviewers identified and extracted information., Results: We observed imbalances in PD genetic studies among URPs. Asian participants from Greater China were described in the majority of the articles published (57%), but other populations were less well studied; for example, Blacks were represented in just 4.0% of the publications. Also, although idiopathic PD was more studied than monogenic forms of the disease, most studies analyzed a limited number of genetic variants. We identified just nine studies using a genome-wide approach published up to 2021, including URPs., Conclusion: This review provides insight into the significant lack of population diversity in PD research highlighting the immediate need for better representation. The Global Parkinson's Genetics Program (GP2) and similar initiatives aim to impact research in URPs, and the early metrics presented here can be used to measure progress in the field of PD genetics in the future. © 2022 International Parkinson and Movement Disorder Society., (© 2022 International Parkinson and Movement Disorder Society.)

Background: Movement disorders have different prevalence in different regions and they are little studied in Africa., Objectives: Evaluate the prevalence and determine the spectrum of movement disorders in the first specialized center in Senegal., Methods: It was a prospective study over on 18 months in adult outpatient clinic. Demographic, clinical, paraclinical data, including genetic test in collaboration with the Queen Square Institute of Neurology at UCL were collected., Results: One hundred and thirty four patients were followed up, representing a prevalence of 4.7%. Men represented 56% for a sex ratio of 1.3. The mean age of population was 47.7 ± 18 years with limits ranging from 16 to 81 years. Eighty-one patients (60.4%) had hyperkinetic and 53 patients (39.6%) had hypokinetic movements. Twenty-nine patients (21.6%) had tremors and 18 (13.4%) had dystonic movements. Ataxia and choreic movements were respectively in 11 (8.2%) and 10 patients (7.5%). Twenty-four patients (17.9%) were from a first-degree consanguineous. A genetic test on saliva samples was done in 16 patients (11.9%) and confirmed Huntington's disease in 8 patients of 6 families. Parkinson disease was the most frequent etiology (32.8%) followed by essential tremor (12.7%) and psychogenic tremor in 7.5%. Stroke accounted for 6% of the causes of MD (tremor, ballism, dystonia, ataxia and parkinsonism) and no etiology was found in 9%., Conclusion: The spectrum of movement disorders is very heterogeneous with a non-negligible frequency and diverse etiologies in neurological practice in Senegal., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Background: An increased prevalence of Parkinson's disease (PD) disease has been previously reported in subjects with Fabry disease (FD) carrying alpha-galactosidase (GLA) mutations and their first-line relatives. Moreover, decreased alpha-galactosidase A (AGLA) enzymatic activity has been reported among cases with PD compared to controls., Objective: The aim of our study was to determine the prevalence of FD among patients with PD., Methods: We recruited 236 consecutive patients with PD from February 2018 to December 2020. Clinical and sociodemographic data, including the MDS-UPDRS-III scores and HY stage (the Hoehn and Yahr scale), were collected, and in-depth phenotyping was performed in subjects with identified GLA variants. A multistep approach, including standard determination of AGLA activity and LysoGb3 in males, and next-generation based GLA sequencing in all females and males with abnormal AGLA levels was performed in a routine diagnostic setting., Results: The mean age of our patients was 68.9 ± 8.9 years, 130 were men (55.1%), and the mean disease duration was 7.77 ± 5.35 years. Among 130 men, AGLA levels were low in 20 patients (15%), and subsequent Lyso-Gb3 testing showed values within the reference range for all tested subjects. In 126 subsequently genetically tested patients, four heterozygous p.(Asp313Tyr) GLA variants (3.2%, MAF 0.016) were identified; all were females. None of the 4 GLA variant carriers identified had any clinical manifestation suggestive of FD., Conclusions: The results of this study suggest a possible relationship between FD and PD in a small proportion of cases. Nevertheless, the GLA variant found in our cohort is classified as a variant of unknown significance. Therefore, its pathogenic causative role in the context of PD needs further elucidation, and these findings should be interpreted with caution., Competing Interests: The authors have no conflicts of interest., (Copyright © 2022 Alexandra Lackova et al.)

Introduction: Sixteen subjects with biallelic WARS2 variants encoding the tryptophanyl mitochondrial aminoacyl-tRNA synthetase, presenting with a neonatal- or infantile-onset mitochondrial disease, have been reported to date. Here we present six novel cases with WARS2-related diseases and expand the spectrum to later onset phenotypes including dopa-responsive early-onset parkinsonism and progressive myoclonus-ataxia., Methods: Six individuals from four families underwent whole-exome sequencing within research and diagnostic settings. Following the identification of a genetic defect, in-depth phenotyping and protein expression studies were performed., Results: A relatively common (gnomAD MAF = 0.0033) pathogenic p.(Trp13Gly) missense variant in WARS2 was detected in trans in all six affected individuals in combination with different pathogenic alleles (exon 2 deletion in family 1; p.(Leu100del) in family 2; p.(Gly50Asp) in family 3; and p.(Glu208*) in family 4). Two subjects presented with action tremor around age 10-12 years and developed tremor-dominant parkinsonism with prominent neuropsychiatric features later in their 20s. Two subjects presented with a progressive myoclonus-ataxia dominant phenotype. One subject presented with spasticity, choreo-dystonia, myoclonus, and speech problems. One subject presented with speech problems, ataxia, and tremor. Western blotting analyses in patient-derived fibroblasts showed a markedly decreased expression of the full-length WARS2 protein in both subjects carrying p.(Trp13Gly) and an exon-2 deletion in compound heterozygosity., Conclusions: This study expands the spectrum of the disease to later onset phenotypes of early-onset tremor-dominant parkinsonism and progressive myoclonus-ataxia phenotypes., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Background: Data on non-motor symptoms (NMS) in black Africans with Parkinson's disease (PD) are sparse., Objective: To describe the profile of NMS in the Nigeria PD Registry (NPDR) cohort and explore the relationship between NMS and PD motor phenotype., Methods: We conducted a cross-sectional study of the frequency and burden of NMS, based on the non-motor symptoms scale (NMSS) and the Chaudhuri method respectively in our cohort. Baseline demographics, disease characteristics (Hoehn and Yahr stage, MDS-UPDRS total score and Part III motor score), motor phenotype (based on Stebbin et al's algorithm), and levodopa equivalent daily dose (LEDD) were documented., Results: Data are presented for 825 PD whose mean age at study was 63.7 ± 10.1 years, female sex-221 [26.8%] while median PD duration was 36 months. PD phenotypes included tremor-dominant 466 (56.5%), postural instability and gait disorder (PIGD) 259 (31.4%), and indeterminate 100 (12.1%). 82.6% were on treatment (median LEDD of 500 mg/24 hours). 804 (97.5%) endorsed at least 1 NMS. The median NMSS score was 26.0 while subscores for urinary and sexual function domains were significantly higher in males ( P  < 0.05). PIGD-PD had more frequent NMS and higher frequency of severe/very severe NMSS burden ( P  = 0.000 for both). Nocturia and fatigue were the most prevalent NMS overall and across motor subtypes. PIGD phenotype and total UPDRS scores were the independent determinants of NMSS scores ( P  = 0.000)., Conclusion: The profile and burden of NMS, and association with motor subtype in our black African cohort is largely similar to descriptions from other populations., Competing Interests: There was no source of funding for this study and all authors have no conflicts of interest to declare., (© 2021 International Parkinson and Movement Disorder Society.)

Leucine-rich repeat kinase 2 (LRRK2) gene mutations are the most common genetic cause of Parkinson's disease (PD). More than 300 rare LRRK2 variants have been described, with approximately 17 having confirmed or probable pathogenic role in PD. The distribution differs across ethnic groups, but no PD-related LRRK2 pathogenic variant has been described in persons of Black African ancestry within or outside Africa. We previously reported the absence of LRRK2 p.Gly2019Ser mutation in 126 PD and 55 controls from Nigeria. Using Kompetitive Allele Specific Polymerase Chain Reaction, we screened a new cohort of 92 Nigerians with PD and 210 ethnically matched controls for 12 rare LRRK2 variants shown to be pathogenic in other ethnic populations, including p.Gly2019Ser, p.Arg1441His, p.Gly2385Arg, p.Ala419Val, p.Arg1628Pro, p.Pro755Leu, p.Ile2020Thr, and Tyr1699Cys. All were absent in PD and controls, endorsing our previous findings and confirming that rare LRRK2 pathogenic variants reported in Caucasians, Asians, and persons of mixed ancestry are absent in West Africans. Future studies applying next generation sequencing are necessary to explore novel LRRK2 variants indigenous to Black Africans., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Rationale: Biomarker research for Alzheimer's disease (AD) has grown rapidly in recent years, ensuing the integration of the AD fluid biomarker profile: Aβ1-42, t-tau, and p-tau 181 , into clinical and research criteria. However, current insights of AD arise almost exclusively from studies on white individuals. Some studies have revealed that epidemiology, clinical features, and genetics of AD show variations between individuals from black and white backgrounds, conveying the importance of ethnoracial differences, and the possibility of such differences also influencing AD biomarker levels. This systematic review explored whether AD fluid biomarker levels differ between African American (AA) or Black African and white groups., Aim: To compare AD fluid biomarkers (Aβ1-42, p-tau 181 , and t-tau) levels between AA or Black Africans and white individuals., Method: PubMed, Scopus, and other sources were explored for studies that quantified AD biomarkers in biological fluid from whites and AA or Black African groups. Meta-analyses were performed to find the standardized mean difference for biomarkers that were quantified in ≥3 studies., Results: Five studies were included; studies on Black Africans were not found. The meta-analyses found CSF t-tau and p-tau 181 were consistently lower in AA than white individuals, in samples with normal cognition or with mild cognitive impairment/dementia., Conclusions: The meta-analyses found significant differences for CSF tau between AA and white individuals with normal cognition and within the dementia spectrum, expressing the importance of taking into account ethnoracial factors when interpreting CSF AD biomarkers levels. However, the generalisability of these differences is restricted by small samples' size, lack of unified methodologies and recruitment's biases within studies; further large multicentre studies with harmonized protocols and sufficient power are imperative to investigate the extent of ethnoracial differences across the spectrum of cognitive decline, with vaster efforts necessary to diversify recruitment., (Copyright © 2020 Elsevier B.V. All rights reserved.)