Unraveling GRIA1 neurodevelopmental disorders: Lessons learned from the p.(Ala636Thr) variant.

Ionotropic glutamate receptors (iGluRs), specifically α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors (AMPARs), play a crucial role in orchestrating excitatory neurotransmission in the brain. AMPARs are intricate assemblies of subunits encoded by four paralogous genes: GRIA1-4. Functional studies have established that rare GRIA variants can alter AMPAR currents leading to a loss- or gain-of-function. Patients affected by rare heterozygous GRIA variants tend to have family specific variants and only few recurrent variants have been reported. We deep-phenotyped a cohort comprising eight unrelated children and adults, harboring a recurrent and well-established disease-causing GRIA1 variant (NM_001114183.1: c.1906G>A, p.(Ala636Thr)). Recurrent symptoms included motor and/or language delay, mild-severe intellectual disability, behavioral and psychiatric comorbidities, hypotonia and epilepsy. We also report challenges in social skills, autonomy, living and work situation, and occupational levels. Furthermore, we compared their clinical manifestations in relation to those documented in patients presenting with rare heterozygous variants at analogous positions within paralogous genes. This study provides unprecedented details on the neurodevelopmental outcomes, cognitive abilities, seizure profiles, and behavioral abnormalities associated with p.(Ala636Thr) refining and broadening the clinical phenotype.

Epilepsy and overgrowth-intellectual disability syndromes: a patient organization perspective on collaborating to accelerate pathways to treatment.

Overgrowth-intellectual disability (OGID) syndromes are a collection of rare genetic disorders with overlapping clinical profiles. In addition to the cardinal features of general overgrowth (height and/or head circumference at least two standard deviations above the mean) and some degree of intellectual disability, the OGID syndromes are often associated with neurological anomalies including seizures. In an effort to advance research in directions that will generate meaningful treatments for people with OGID syndromes, a new collaborative partnership called the Overgrowth Syndromes Alliance (OSA) formed in 2023. By taking a phenotype-first approach, OSA aims to unite research and patient communities traditionally siloed by genetic disorder. OSA has galvanized OGID patient organizations around shared interests and developed a research roadmap to identify and address our community's greatest unmet needs. Here, we describe the literature regarding seizures among those with overgrowth syndromes and present the OSA Research Roadmap. This patient-driven guide outlines the milestones essential to reaching the outcome of effective treatments for OGID syndromes and offers resources for reaching those milestones.

Working together to speed up treatments for rare genetic syndromes linked to excessive growth and intellectual disability To address the shared challenges experienced among those affected by overgrowth­intellectual disability (OGID) syndromes, we recently formed the Overgrowth Syndromes Alliance (OSA). The OSA unites patient advocacy organizations that have typically worked independently of one another, in hopes of accelerating our progress toward treatments. Here, we summarize the OGID syndromes represented by the OSA, the prevalence of seizures in these disorders, and efforts by the OSA to tackle the most pressing needs of the overgrowth community. We also present the steps patient organizations can take in pursuit of developing treatments. We hope the work of our alliance can be a template for creating collaborative, patient-led advances in diagnosis, management guidelines, and, eventually, treatment of rare genetic disorders.

Massive open online courses (MOOCs) in genomic variant interpretation: An innovative education strategy for the growing genetic counselor workforce.

The growth in genomic testing in healthcare requires a highly trained specialist workforce to ensure evidence based clinical germline variant interpretation. Genetic counselors form a core part of the clinical genomics multidisciplinary team (MDT) and represent a growing workforce participating in variant interpretation from data analysis to the patient consultation. Standardized, high-quality variant interpretation training for Genetic Counselors has historically been ad hoc and variable, with existing programs lacking capacity to reach the entire workforce. To address the requirement for scalable variant interpretation training for genomics healthcare professionals (HCPs), two Massive Open Online Courses (MOOCs) were developed. We analyzed the data from 17 Genetic counselors, as part of an evaluation cohort completing the first run of these MOOCs. Overall genetic counselors enjoyed the courses, felt they were clinically relevant and would recommend them to colleagues. Common challenges amongst the genetic counseling workforces included utilizing relevant databases and finding time in the workday to complete training. These findings suggest MOOCs could be an acceptable option to ensure a consistent and transferrable high standard of training, complimentary to existing curricula. They also hold the potential to facilitate large-scale education to update the genetic counseling workforce when changes in variant interpretation guidance occur.

Evaluation of two Massive Open Online Courses (MOOCs) in genomic variant interpretation for the NHS workforce.

BACKGROUND: The implementation of the National Genomic Medicine Service in the UK has increased patient access to germline genomic testing. Increased testing leads to more genetic diagnoses but does result in the identification of genomic variants of uncertain significance (VUS). The rigorous process of interpreting these variants requires multi-disciplinary, highly trained healthcare professionals (HCPs). To meet this training need, we designed two Massive Open Online Courses (MOOCs) for HCPs involved in germline genomic testing pathways: Fundamental Principles (FP) and Inherited Cancer Susceptibility (ICS). METHODS: An evaluation cohort of HCPs involved in genomic testing were recruited, with additional data also available from anonymous self-registered learners to both MOOCs. Pre- and post-course surveys and in-course quizzes were used to assess learner satisfaction, confidence and knowledge gained in variant interpretation. In addition, granular feedback was collected on the complexity of the MOOCs to iteratively improve the resources. RESULTS: A cohort of 92 genomics HCPs, including clinical scientists, and non-genomics clinicians (clinicians working in specialties outside of genomics) participated in the evaluation cohort. Between baseline and follow-up, total confidence scores improved by 38% (15.2/40.0) (95% confidence interval [CI] 12.4-18.0) for the FP MOOC and 54% (18.9/34.9) (95%CI 15.5-22.5) for the ICS MOOC (p < 0.0001 for both). Of those who completed the knowledge assessment through six summative variant classification quizzes (V1-6), a mean of 79% of respondents classified the variants such that correct clinical management would be undertaken (FP: V1 (73/90) 81% Likely Pathogenic/Pathogenic [LP/P]; V2 (55/78) 70% VUS; V3 (59/75) 79% LP/P; V4 (62/72) 86% LP/LP. ICS: V5 (66/91) 73% VUS; V6 (76/88) 86% LP/P). A non-statistically significant higher attrition rate was seen amongst the non-genomics workforce when compared to genomics specialists for both courses. More participants from the non-genomics workforce rated the material as "Too Complex" (FP n = 2/7 [29%], ICS n = 1/5 [20%]) when compared to the specialist genomics workforce (FP n = 1/43 [2%], ICS n = 0/35 [0%]). CONCLUSIONS: After completing one or both MOOCs, self-reported confidence in genomic variant interpretation significantly increased, and most respondents could correctly classify variants such that appropriate clinical management would be instigated. Genomics HCPs reported higher satisfaction with the level of content than the non-genomics clinicians. The MOOCs provided foundational knowledge and improved learner confidence, but should be adapted for different workforces to maximise the benefit for clinicians working in specialties outside of genetics.

Implementation of precision medicine in healthcare-A European perspective.

The technical development of high-throughput sequencing technologies and the parallel development of targeted therapies in the last decade have enabled a transition from traditional medicine to personalized treatment and care. In this way, by using comprehensive genomic testing, more effective treatments with fewer side effects are provided to each patient-that is, precision or personalized medicine (PM). In several European countries-such as in England, France, Denmark, and Spain-the governments have adopted national strategies and taken "top-down" decisions to invest in national infrastructure for PM. In other countries-such as Sweden, Germany, and Italy with regionally organized healthcare systems-the profession has instead taken "bottom-up" initiatives to build competence networks and infrastructure to enable equal access to PM. In this review, we summarize key learnings at the European level on the implementation process to establish sustainable governance and organization for PM at the regional, national, and EU/international levels. We also discuss critical ethical and legal aspects of implementing PM, and the importance of access to real-world data and performing clinical trials for evidence generation, as well as the need for improved reimbursement models, increased cross-disciplinary education and patient involvement. In summary, PM represents a paradigm shift, and modernization of healthcare and all relevant stakeholders-that is, healthcare, academia, policymakers, industry, and patients-must be involved in this system transformation to create a sustainable, non-siloed ecosystem for precision healthcare that benefits our patients and society at large.

The PHF21A neurodevelopmental disorder: an evaluation of clinical data from 13 patients.

Potocki-Shaffer syndrome (PSS) is a rare neurodevelopmental disorder caused by deletions involving the 11p11.2-p12 region, encompassing the plant homeodomain finger protein 21A (PHF21A) gene. PHF21A has an important role in epigenetic regulation and PHF21A variants have previously been associated with a specific disorder that, whilst sharing some features of PSS, has notable differences. This study aims to expand the phenotype, particularly in relation to overgrowth, associated with PHF21A variants. Analysis of phenotypic data was undertaken on 13 individuals with PHF21A constitutional variants including four individuals described in the current series. Of those individuals where data were recorded, postnatal overgrowth was reported in 5/6 (83%). In addition, all had both an intellectual disability and behavioural issues. Frequent associations included postnatal hypotonia (7/11, 64%); and at least one afebrile seizure episode (6/12, 50%). Although a recognizable facial gestalt was not associated, subtle dysmorphic features were shared amongst some individuals and included a tall broad forehead, broad nasal tip, anteverted nares and full cheeks. We provide further insight into the emerging neurodevelopmental syndrome associated with PHF21A disruption. We present some evidence that PHF21A might be considered a new member of the overgrowth-intellectual disability syndrome (OGID) family.

Mainstreaming of genomics in oncology: a nationwide survey of the genomics training needs of UK oncologists.

OBJECTIVE: Genomics is rapidly changing treatment paradigms for cancers, obligating oncologists to have good genomics knowledge. Through this survey, we aimed to assess the current understanding of cancer genomics among UK oncologists. METHODS: We conducted a web-based nation-wide self-assessment survey of the cancer genomics knowledge of UK clinical and medical oncology trainees and consultants. RESULTS: In total, 150 oncologists (81 consultants and 69 trainees) responded, representing 10% of UK oncologists.Formal training in genomics had not been received by 38.7% of oncologists and 92.7% identified a need for additional genomics training.In total, 71.3% self-reported to have good knowledge of defining somatic and germline mutations, falling to 35.3% for understanding principles of gene expression and regulation. Knowledge of cancer-predisposing syndromes was highest for Lynch syndrome (40.7% good knowledge) and lowest for multiple endocrine neoplasia (14.0% good knowledge).Overall, 49.0% of respondents had consented patients for germline testing, but 80.7% reported a lack of training in genetic counselling. CONCLUSION: Large knowledge gaps have been identified through this survey, highlighting the need for incorporation of improved formal training in cancer genomics for consultants and trainees, with an aim to equip oncologists for advances in clinical practice and to take up genetic mainstreaming confidently.

ATP6V0C variants impair V-ATPase function causing a neurodevelopmental disorder often associated with epilepsy.

The vacuolar H+-ATPase is an enzymatic complex that functions in an ATP-dependent manner to pump protons across membranes and acidify organelles, thereby creating the proton/pH gradient required for membrane trafficking by several different types of transporters. We describe heterozygous point variants in ATP6V0C, encoding the c-subunit in the membrane bound integral domain of the vacuolar H+-ATPase, in 27 patients with neurodevelopmental abnormalities with or without epilepsy. Corpus callosum hypoplasia and cardiac abnormalities were also present in some patients. In silico modelling suggested that the patient variants interfere with the interactions between the ATP6V0C and ATP6V0A subunits during ATP hydrolysis. Consistent with decreased vacuolar H+-ATPase activity, functional analyses conducted in Saccharomyces cerevisiae revealed reduced LysoSensor fluorescence and reduced growth in media containing varying concentrations of CaCl2. Knockdown of ATP6V0C in Drosophila resulted in increased duration of seizure-like behaviour, and the expression of selected patient variants in Caenorhabditis elegans led to reduced growth, motor dysfunction and reduced lifespan. In summary, this study establishes ATP6V0C as an important disease gene, describes the clinical features of the associated neurodevelopmental disorder and provides insight into disease mechanisms.

Socio-economic deprivation and cancer incidence in England: Quantifying the role of smoking.

BACKGROUND: More deprived populations typically experience higher cancer incidence rates and smoking prevalence compared to less deprived populations. We calculated the proportion of cancer cases attributable to smoking by socio-economic deprivation in England and estimated the impact smoking has on the deprivation gap for cancer incidence. METHODS: Data for cancer incidence (2013-2017), smoking prevalence (2003-2007) and population estimates (2013-2017) were split by sex, age-group and deprivation quintile. Relative risk estimates from meta-analyses were used to estimate the population attributable fraction (PAF) for 15 cancer types associated with smoking. The deprivation gap was calculated using age-specific incidence rates by deprivation quintile. RESULTS: Smoking-related cancer PAFs in England are 2.2 times larger in the most deprived quintile compared to the least deprived quintile (from 9.7% to 21.1%). If everyone had the same smoking prevalence as the least deprived quintile, 20% of the deprivation gap in cancer incidence could have been prevented. If nobody smoked, 61% of the deprivation gap could have been prevented. CONCLUSIONS: The majority of the deprivation gap in cancer incidence could have been prevented in England between 2013-2017 if nobody had smoked. Policy makers should ensure that tobacco control policies reduce overall smoking prevalence by tackling smoking inequalities.

Differences in cancer incidence by broad ethnic group in England, 2013-2017.

BACKGROUND: Cancer incidence variation between population groups can inform public health and cancer services. Previous studies have shown cancer incidence rates vary by ethnic group in England. Since their publication, the completeness of ethnicity recording in cancer data has improved, and relevant inequalities (e.g. risk factor prevalence and healthcare access) may have changed. METHODS: Age-standardised incidence rates were calculated for Asian, Black, Mixed/Multiple and White ethnic groups in England in 2013-2017, using almost 3 million diagnoses across 31 cancer sites. Rate ratios were calculated with the White ethnic group as reference. Sensitivity analyses used imputed ethnicity for cases with missing data and perturbed population estimates. RESULTS: Incidence rates for most cancer sites and ethnic group and sex combinations were lower in non-White minority ethnic groups compared with the corresponding White group, with particularly low rate ratios (below 0.5) for melanoma skin cancer and some smoking-related cancers (lung, bladder and oesophageal cancers). Exceptions included prostate cancer (2.1 times higher in males of Black ethnicity), myeloma (2.7-3.0 times higher in people of Black ethnicity), several gastrointestinal cancers (1.1-1.9 times higher in people of Black ethnicity, 1.4-2.2 times higher in people of Asian ethnicity), Hodgkin lymphoma (1.1 times higher in males of Asian ethnicity, 1.3 times higher in males of Black ethnicity) and thyroid cancers (1.4 times higher in people of Asian ethnicity, 1.2 times higher in people of Black ethnicity). Sensitivity analyses did not materially alter these results (rate ratios changed by a maximum of 12 percentage points, the direction and significance of results were unchanged in all but two cancer site/sex/ethnic group combinations). CONCLUSIONS: People of non-White minority ethnicity in England generally have lower cancer risk than the White population, though there are a number of notable exceptions. These results should galvanise efforts to better understand the reasons for this variation, and the possible impact on cancer services, patient experiences and outcomes.

Updated fraction of cancer attributable to lifestyle and environmental factors in Denmark in 2018.

Environmental exposures and avoidable risk factors account for a large proportion of cancer burden. Exposures and lifestyle vary over time and between populations, which calls for updated and population-specific quantification of how various avoidable risk factors influence cancer risk to plan and design rational and targeted prevention initiatives. The study considered 12 risk-factor groups categorized as class I carcinogens by IARC/WCRF. Exposure data was derived from national studies and surveys and were linked to cancer incidence in 2018 based on the nationwide Danish Cancer Registry. In 2018, 23,078 men and 21,196 women were diagnosed with cancer excluding non-melanoma skin cancer, in Denmark. Of these, 14,235 (32.2%) were estimated to be attributable to avoidable class I carcinogens. Tobacco smoking accounted for 14.6% of total cancers, followed by UV-radiation that accounted for 5.8%. Based on exposure data from 2008, one-third of the cancers in Denmark in 2018 are estimated to be caused by class I carcinogens with tobacco use being the main contributor followed by UV-radiation. Our results should be integrated with public health policies to effectively increase awareness and promote strategies to decrease risk factor exposures at population level.

Potential Efficacy of Nutrient Supplements for Treatment or Prevention of COVID-19.

COVID-19 (COronaVIrus Disease of 2019), the disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), represents an ongoing global health challenge and the deadliest epidemic coronavirus outbreak to date. Early sequencing of the viral genome and knowledge from past coronavirus outbreaks (SARS-CoV-1 and Middle East Respiratory Syndrome, MERS) has led to rapid advances in knowledge of how the virus spreads and infects human hosts. Unfortunately, advancing knowledge has not yet produced a treatment that substantially lowers morbidity or mortality and only recently resulted in the development of a vaccine that prevents severe disease. Mounting evidence supports the notion that dietary supplementation of key essential nutrients may contribute to the body's defenses against infection as well as bolster the body's responses to infection. Evidence supporting the potential beneficial roles of vitamin C, vitamin D, zinc, and B3 vitamins is reviewed here, revealing a combination of basic research elucidating underlying mechanisms of action, preclinical studies and human intervention studies has led to the proliferation of registered clinical trials on COVID-19. Overall, the data suggest this collection of nutrients has a promising impact on reducing the risk and/or severity of COVID-19, although firm conclusions await the results of these trials.

Computational analysis of spoken language in acute psychosis and mania.

OBJECTIVES: This study aimed to (1) determine the feasibility of collecting behavioral data from participants hospitalized with acute psychosis and (2) begin to evaluate the clinical information that can be computationally derived from such data. METHODS: Behavioral data was collected across 99 sessions from 38 participants recruited from an inpatient psychiatric unit. Each session started with a semi-structured interview modeled on a typical "clinical rounds" encounter and included administration of the Positive and Negative Syndrome Scale (PANSS). ANALYSIS: We quantified aspects of participants' verbal behavior during the interview using lexical, coherence, and disfluency features. We then used two complementary approaches to explore our second objective. The first approach used predictive models to estimate participants' PANSS scores from their language features. Our second approach used inferential models to quantify the relationships between individual language features and symptom measures. RESULTS: Our predictive models showed promise but lacked sufficient data to achieve clinically useful accuracy. Our inferential models identified statistically significant relationships between numerous language features and symptom domains. CONCLUSION: Our interview recording procedures were well-tolerated and produced adequate data for transcription and analysis. The results of our inferential modeling suggest that automatic measurements of expressive language contain signals highly relevant to the assessment of psychosis. These findings establish the potential of measuring language during a clinical interview in a naturalistic setting and generate specific hypotheses that can be tested in future studies. This, in turn, will lead to more accurate modeling and better understanding of the relationships between expressive language and psychosis.

Systematic Profiling of DNMT3A Variants Reveals Protein Instability Mediated by the DCAF8 E3 Ubiquitin Ligase Adaptor.

Clonal hematopoiesis is a prevalent age-related condition associated with a greatly increased risk of hematologic disease; mutations in DNA methyltransferase 3A (DNMT3A) are the most common driver of this state. DNMT3A variants occur across the gene with some particularly associated with malignancy, but the functional relevance and mechanisms of pathogenesis of the majority of mutations are unknown. Here, we systematically investigated the methyltransferase activity and protein stability of 253 disease-associated DNMT3A mutations, and found that 74% were loss-of-function mutations. Half of these variants exhibited reduced protein stability and, as a class, correlated with greater clonal expansion and acute myeloid leukemia development. We investigated the mechanisms underlying the instability using a CRISPR screen and uncovered regulated destruction of DNMT3A mediated by the DCAF8 E3 ubiquitin ligase adaptor. We establish a new paradigm to classify novel variants that has prognostic and potential therapeutic significance for patients with hematologic disease. SIGNIFICANCE: DNMT3A has emerged as the most important epigenetic regulator and tumor suppressor in the hematopoietic system. Our study represents a systematic and high-throughput method to characterize the molecular impact of DNMT3A missense mutations and the discovery of a regulated destruction mechanism of DNMT3A offering new prognostic and future therapeutic avenues.See related commentary by Ma and Will, p. 23.This article is highlighted in the In This Issue feature, p. 1.

Quantifying evidence toward pathogenicity for rare phenotypes: The case of succinate dehydrogenase genes, SDHB and SDHD.

PURPOSE: The weight of the evidence to attach to observation of a novel rare missense variant in SDHB or SDHD in individuals with the rare neuroendocrine tumors, pheochromocytomas and paragangliomas (PCC/PGL), is uncertain. METHODS: We compared the frequency of SDHB and SDHD very rare missense variants (VRMVs) in 6328 and 5847 cases of PCC/PGL, respectively, with that of population controls to generate a pan-gene VRMV likelihood ratio (LR). Via windowing analysis, we measured regional enrichments of VRMVs to calculate the domain-specific VRMV-LR (DS-VRMV-LR). We also calculated subphenotypic LRs for variant pathogenicity for various clinical, histologic, and molecular features. RESULTS: We estimated the pan-gene VRMV-LR to be 76.2 (54.8-105.9) for SDHB and 14.8 (8.7-25.0) for SDHD. Clustering analysis revealed an SDHB enriched region (ɑɑ 177-260, P = .001) for which the DS-VRMV-LR was 127.2 (64.9-249.4) and an SDHD enriched region (ɑɑ 70-114, P = .000003) for which the DS-VRMV-LR was 33.9 (14.8-77.8). Subphenotypic LRs exceeded 6 for invasive disease (SDHB), head-and-neck disease (SDHD), multiple tumors (SDHD), family history of PCC/PGL, loss of SDHB staining on immunohistochemistry, and succinate-to-fumarate ratio >97 (SDHB, SDHD). CONCLUSION: Using methodology generalizable to other gene-phenotype dyads, the LRs relating to rarity and phenotypic specificity for a single observation in PCC/PGL of a SDHB/SDHD VRMV can afford substantial evidence toward pathogenicity.

Social Ecological Dynamics of Catchment Resilience.

Catchment resilience is the capacity of a combined social ecological system, comprised of water, land, ecological resources and communities in a river basin, to deal with sudden shocks and gradual changes, and to adapt and self-organize for progressive change and transform itself for sustainability. This paper proposes that analysis of catchments as social ecological systems can provide key insights into how social and ecological dynamics interact and how some of the negative consequences of unsustainable resource use or environmental degradation can be ameliorated. This requires recognition of the potential for community resilience as a core element of catchment resilience, and moves beyond more structural approaches to emphasize social dynamics. The proposals are based on a review of social ecological systems research, on methods for analyzing community resilience, and a review of social science and action research that suggest ways of generating resilience through community engagement. These methods and approaches maximize insights into the social dynamics of catchments as complex adaptive systems to inform science and practice.

Delineating the Smith-Kingsmore syndrome phenotype: Investigation of 16 patients with the MTOR c.5395G > A p.(Glu1799Lys) missense variant.

Smith-Kingsmore Syndrome (SKS) is a rare genetic syndrome associated with megalencephaly, a variable intellectual disability, autism spectrum disorder, and MTOR gain of function variants. Only 30 patients with MTOR missense variants are published, including 14 (47%) with the MTOR c.5395G>A p.(Glu1799Lys) variant. Limited phenotypic data impacts the quality of information delivered to families and the robustness of interpretation of novel MTOR missense variation. This study aims to improve our understanding of the SKS phenotype through the investigation of 16 further patients with the MTOR c.5395G>A p.(Glu1799Lys) variant. Through the careful phenotypic evaluation of these 16 patients and integration with data from 14 previously reported patients, we have defined major (100% patients) and frequent (>15%) SKS clinical characteristics and, using these data, proposed guidance for evidence-based management. In addition, in the absence of functional studies, we suggest that the combination of the SKS major clinical features of megalencephaly (where the head circumference is at least 3SD) and an intellectual disability with a de novo MTOR missense variant (absent from population databases) should be considered diagnostic for SKS.

Multiple impact pathways of the 2015-2016 El Niño in coastal Kenya.

The 2015-2016 El Niño had large impacts globally. The effects were not as great as anticipated in Kenya, however, leading some commentators to call it a 'non-event'. Our study uses a novel combination of participatory Climate Vulnerability and Capacity Analysis tools, and new and existing social and biophysical data, to analyse vulnerability to, and the multidimensional impacts of, the 2015-2016 El Niño episode in southern coastal Kenya. Using a social-ecological systems lens and a unique dataset, our study reveals impacts overlooked by conventional analysis. We show how El Niño stressors interact with and amplify existing vulnerabilities to differentially impact local ecosystems and people. The policy significance of this finding is that the development of specific national capacities to deal with El Niño events is insufficient; it will be necessary to also address local vulnerabilities to everyday and recurrent stressors and shocks to build resilience to the effects of El Niño and other extremes in climate and weather.

Early-Onset Parkinsonism Is a Manifestation of the PPP2R5D p.E200K Mutation.

PPP2R5D-related neurodevelopmental disorder is characterized by a range of neurodevelopmental and behavioral manifestations. We report the association of early-onset parkinsonism with the PPP2R5D p.E200K mutation. Clinical characterization and exome sequencing were performed on three patients, with postmortem neuropathologic examination for one patient. All patients had mild developmental delay and developed levodopa-responsive parkinsonism between the ages of 25 and 40 years. The PPP2R5D c.598G>A (p.E200K) mutation was identified in all patients. Neuropathologic examination demonstrated uneven, focally severe neuronal loss and gliosis in the substantia nigra pars compacta, without Lewy bodies. Our findings suggest the PPP2R5D p.E200K mutation to be a possible new cause of early-onset parkinsonism. ANN NEUROL 2020;88:1028-1033.