High-throughput screening for small-molecule stabilizers of misfolded glucocerebrosidase in Gaucher disease and Parkinson's disease.

Glucocerebrosidase (GCase) is implicated in both a rare, monogenic disorder (Gaucher disease, GD) and a common, multifactorial condition (Parkinson's disease, PD); hence, it is an urgent therapeutic target. To identify correctors of severe protein misfolding and trafficking obstruction manifested by the pathogenic L444P-variant of GCase, we developed a suite of quantitative, high-throughput, cell-based assays. First, we labeled GCase with a small proluminescent HiBiT peptide reporter tag, enabling quantitation of protein stabilization in cells while faithfully maintaining target biology. TALEN-based gene editing allowed for stable integration of a single HiBiT-GBA1 transgene into an intragenic safe-harbor locus in GBA1-knockout H4 (neuroglioma) cells. This GD cell model was amenable to lead discovery via titration-based quantitative high-throughput screening and lead optimization via structure-activity relationships. A primary screen of 10,779 compounds from the NCATS bioactive collections identified 140 stabilizers of HiBiT-GCase-L444P, including both pharmacological chaperones (ambroxol and noninhibitory chaperone NCGC326) and proteostasis regulators (panobinostat, trans-ISRIB, and pladienolide B). Two complementary high-content imaging-based assays were deployed to triage hits: The fluorescence-quenched substrate LysoFix-GBA captured functional lysosomal GCase activity, while an immunofluorescence assay featuring antibody hGCase-1/23 directly visualized GCase lysosomal translocation. NCGC326 was active in both secondary assays and completely reversed pathological glucosylsphingosine accumulation. Finally, we tested the concept of combination therapy by demonstrating synergistic actions of NCGC326 with proteostasis regulators in enhancing GCase-L444P levels. Looking forward, these physiologically relevant assays can facilitate the identification, pharmacological validation, and medicinal chemistry optimization of small molecules targeting GCase, ultimately leading to a viable therapeutic for GD and PD.

Gaucher disease glucocerebrosidase and α-synuclein form a bidirectional pathogenic loop in synucleinopathies.

Parkinson's disease (PD), an adult neurodegenerative disorder, has been clinically linked to the lysosomal storage disorder Gaucher disease (GD), but the mechanistic connection is not known. Here, we show that functional loss of GD-linked glucocerebrosidase (GCase) in primary cultures or human iPS neurons compromises lysosomal protein degradation, causes accumulation of α-synuclein (α-syn), and results in neurotoxicity through aggregation-dependent mechanisms. Glucosylceramide (GlcCer), the GCase substrate, directly influenced amyloid formation of purified α-syn by stabilizing soluble oligomeric intermediates. We further demonstrate that α-syn inhibits the lysosomal activity of normal GCase in neurons and idiopathic PD brain, suggesting that GCase depletion contributes to the pathogenesis of sporadic synucleinopathies. These findings suggest that the bidirectional effect of α-syn and GCase forms a positive feedback loop that may lead to a self-propagating disease. Therefore, improved targeting of GCase to lysosomes may represent a specific therapeutic approach for PD and other synucleinopathies.

Consensus Guidance for Genetic Counseling in GBA1 Variants: A Focus on Parkinson's Disease.

Glucocerebrosidase (GBA1) variants constitute numerically the most common known genetic risk factor for Parkinson's disease (PD) and are distributed worldwide. Access to GBA1 genotyping varies across the world and even regionally within countries. Guidelines for GBA1 variant counseling are evolving. We review the current knowledge of the link between GBA1 and PD, and discuss the practicalities of GBA1 testing. Lastly, we provide a consensus for an approach to counseling people with GBA1 variants, notably the communication of PD risk. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Phenotypic consequences of GBA1 pathological variant R463C (p.R502C).

Gaucher disease (GD) is an autosomal recessively inherited lysosomal storage disorder caused by biallelic pathological variants in the GBA1 gene. Patients present along a broad clinical spectrum, and phenotypes are often difficult to predict based on genotype alone. The variant R463C (p.Arg502Cys) exemplifies this challenge. To better characterize its different clinical presentations, we examined the records of 25 current and historical patients evaluated at the National Institutes of Health. Nine patients were classified as GD1, 14 were classified as GD3, and two had an ambiguous diagnosis between GD1 and GD3. In addition, we reviewed the published literature in PubMed and Web of Science through December 2023, identifying 62 cases with an R463C variant from 18 countries. Within the NIH cohort, the most common second variants were N370S (p.N409S) and L444P (p.L483P). R463C/L444P was encountered in patients with GD1 and GD3 in both the NIH cohort and worldwide. In the literature, R463C/R463C was also reported in both GD1 and GD3, although sparse phenotypic information was shared. Often the phenotype reflected what might be predicted for the second mutant allele. This diversity of phenotypes emphasizes the need for longitudinal follow-up to assess symptom development and neurological involvement.

A Comparative Biochemical and Pathological Evaluation of Brain Samples from Knock-In Murine Models of Gaucher Disease.

Gaucher disease (GD) is a lysosomal storage disorder stemming from biallelic mutations in GBA1, characterized by glucocerebrosidase dysfunction and glucocerebroside and glucosylsphingosine accumulation. Since phenotypes of murine models of GD often differ from those in patients, the careful characterization of Gba1 mutant mice is necessary to establish their ability to model GD. We performed side-by-side comparative biochemical and pathologic analyses of four murine Gba1 models with genotypes L444P/L444P (p.L483P/p.L483P), L444P/null, D409H/D409H (p.D448H/p.D448H) and D409H/null, along with matched wildtype mice, all with the same genetic background and cage conditions. All mutant mice exhibited significantly lower glucocerebrosidase activity (p < 0.0001) and higher glucosylsphingosine levels than wildtype, with the lowest glucocerebrosidase and the highest glucosylsphingosine levels in mice carrying a null allele. Although glucocerebrosidase activity in L444P and D409H mice was similar, D409H mice showed more lipid accumulation. No Gaucher or storage-like cells were detected in any of the Gba1 mutant mice. Quantification of neuroinflammation, dopaminergic neuronal loss, alpha-synuclein levels and motor behavior revealed no significant findings, even in aged animals. Thus, while the models may have utility for testing the effect of different therapies on enzymatic activity, they did not recapitulate the pathological phenotype of patients with GD, and better models are needed.

New tools can propel research in lysosomal storage diseases.

Historically, the clinical manifestations of lysosomal storage diseases offered an early glimpse into the essential digestive functions of the lysosome. However, it was only recently that the more subtle role of this organelle in the dynamic regulation of multiple cellular processes was appreciated. With the need for precise interrogation of lysosomal interplay in health and disease comes the demand for more sophisticated functional tools. This demand has recently been met with 1) induced pluripotent stem cell-derived models that recapitulate the disease phenotype in vitro, 2) methods for lysosome affinity purification coupled with downstream omics analysis that provide a high-resolution snapshot of lysosomal alterations, and 3) gene editing and CRISPR/Cas9-based functional genomic strategies that enable screening for genetic modifiers of the disease phenotype. These emerging methods have garnered much interest in the field of neurodegeneration, and their use in the field of metabolic disorders is now also steadily gaining momentum. Looking forward, these robust tools should accelerate basic science efforts to understand lysosomal dysfunction distal to substrate accumulation and provide translational opportunities to identify disease-modifying therapies.

Polygenic Parkinson's Disease Genetic Risk Score as Risk Modifier of Parkinsonism in Gaucher Disease.

BACKGROUND: Biallelic pathogenic variants in GBA1 are the cause of Gaucher disease (GD) type 1 (GD1), a lysosomal storage disorder resulting from deficient glucocerebrosidase. Heterozygous GBA1 variants are also a common genetic risk factor for Parkinson's disease (PD). GD manifests with considerable clinical heterogeneity and is also associated with an increased risk for PD. OBJECTIVE: The objective of this study was to investigate the contribution of PD risk variants to risk for PD in patients with GD1. METHODS: We studied 225 patients with GD1, including 199 without PD and 26 with PD. All cases were genotyped, and the genetic data were imputed using common pipelines. RESULTS: On average, patients with GD1 with PD have a significantly higher PD genetic risk score than those without PD (P = 0.021). CONCLUSIONS: Our results indicate that variants included in the PD genetic risk score were more frequent in patients with GD1 who developed PD, suggesting that common risk variants may affect underlying biological pathways. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

Revisiting the diagnosis of Gaucher disease in a family with multiple GBA1 variants.

Our ability to identify different variants in GBA1, the gene mutated in the lysosomal storage disorder Gaucher disease (GD), has greatly improved. We describe a multigenerational family with type 1 GD initially evaluated over three decades ago. Re-evaluating both the genotype and phenotype, we determined that one family member with genotype N370S/T369M (p.N409S/p.T408M), was likely erroneously diagnosed with GD. This case substantiates that GBA1 variant T369M, while mildly reducing glucocerebrosidase activity, does not result in GD. The observation has clinical relevance as cases with this genotype will increasingly be ascertained through screening programs in newborns and in movement disorder clinics.

The D409H variant in GBA1: Challenges in predicting the Gaucher phenotype in the newborn screening era.

Gaucher disease (GD) is an autosomal recessive disorder resulting from glucocerebrosidase deficiency due to pathologic variants in GBA1. While clinically heterogeneous, GD encompasses three types, non-neuronopathic (GD1), acute neuronopathic (GD2), and chronic neuronopathic (GD3). Newborn screening (NBS), which has made remarkable inroads in detecting certain diseases before detrimental health consequences and fatality ensues, is now being piloted for GD in several states and countries. Early on, clinical features of GD2 can overlap with GD3; hence, predicting outcome is challenging. As NBS for GD becomes more available, the increased detection of GD in neonates is inevitable. As a result, health care providers and families will be faced with uncertainty with respect to clinical management. Since more severe GBA1 variants are generally associated with neuronopathic GD, there has been an increased dependence on genotypic information. We present an infant detected by NBS with genotype D409H(p.Asp448His)/RecNciI (p.Leu483Pro; p.Ala495Pro;p.Val499=). To assist in genetic counseling, we performed a retrospective review of other patients in our cohort carrying D409H and reviewed the literature. The study illustrates the challenges faced in counseling for infants with neuronopathic GD, even with known GBA1 variants, and the tough management decisions that can ensue from detection in newborns.

An exploration of knowledge, risk perceptions, and communication in a family with multiple genetic risks for Parkinson's disease.

Genomic testing increasingly challenges health care providers and patients to understand, share, and use information. The provision of polygenic risks is anticipated to complicate comprehension, communication, and risk perception further. This manuscript aims to illuminate the challenges confronting families with multiple genetic risks for Parkinson's disease. Identifying and planning for such issues may prove valuable to family members now and in the future, should neuroprotective or genotype-specific therapies become available. We present qualitative data from interviews with a multi-generational family carrying pathogenic variants in the glucocerebrosidase (GBA1) and leucine-rich repeat kinase 2 (LRRK2) genes which are associated with an increased risk for developing Parkinson's disease (PD). The family includes two brothers (heterozygous for LRRK2 p.G2019S and homozygous for GBA1 p.N409S) and their four descendants. The brothers were concordant for GD and discordant for PD. Genetic counseling and testing were provided to four of the six participants. Two years later, semi-structured interviews were conducted with the initial participants (n = 4) and two additional first-degree relatives. Interviews were transcribed and thematically analyzed, providing the basis for this report. Illuminated topics include the perceived risk of developing PD, recall of genetic information, and family communication. With the expanding use of exome and genome sequencing, we anticipate that genetic counselors will increasingly face the challenges demonstrated by this case involving multiple genetic risks for PD, limited data to clarify risk, and the inherent variability of family communication, genetic knowledge, and risk perception. This clinical case report provides a compelling narrative demonstrating the need for additional research exploring these multifaceted topics relevant to both families facing these challenges and providers striving to assist, support and guide their journey.

Comparison of Transcranial Sonography and [18 F]-Fluorodopa PET Imaging in GBA1 Mutation Carriers.

BACKGROUND: Mutations in GBA1 are a common genetic risk factor for parkinsonism; however, penetrance is incomplete, and biomarkers of future progression to parkinsonism are needed. Both nigral sonography and striatal [18 F]-FDOPA PET assay dopamine system health, but their utility and coherence in this context are unclear. OBJECTIVE: The aim of this study is to evaluate the utility and coherence of these modalities in GBA1-associated parkinsonism. METHODS: A total of 34 patients with GBA1 mutations (7 with parkinsonism) underwent both transcranial studies for substantia nigra echogenicity and [18 F]-FDOPA PET to determine striatal tracer-specific uptake (Ki ). RESULTS: Larger nigral echogenic areas and reduced striatal Ki were exclusively observed in parkinsonian patients. Sonographic and PET measurements showed strong inverse correlations but only in individuals with clinical parkinsonism. CONCLUSIONS: Close correspondence between nigral echogenicity and striatal presynaptic dopamine synthesis capacity observed only in GBA1 carriers with parkinsonism provides validation that these two modalities may conjointly capture aspects of the biology underlying clinical parkinsonism but raises questions about their utility as predictive tools in at-risk subjects. © 2022 International Parkinson and Movement Disorder Society.

Neuropathological Features of Gaucher Disease and Gaucher Disease with Parkinsonism.

Deficient acid ß-glucocerebrosidase activity due to biallelic mutations in GBA1 results in Gaucher disease (GD). Patients with this lysosomal storage disorder exhibit a wide range of associated manifestations, spanning from virtually asymptomatic adults to infants with severe neurodegeneration. While type 1 GD (GD1) is considered non-neuronopathic, a small subset of patients develop parkinsonian features. Variants in GBA1 are also an important risk factor for several common Lewy body disorders (LBDs). Neuropathological examinations of patients with GD, including those who developed LBDs, are rare. GD primarily affects macrophages, and perivascular infiltration of Gaucher macrophages is the most common neuropathologic finding. However, the frequency of these clusters and the affected anatomical region varies. GD affects astrocytes, and, in neuronopathic GD, neurons in cerebral cortical layers 3 and 5, layer 4b of the calcarine cortex, and hippocampal regions CA2-4. In addition, several reports describe selective degeneration of the cerebellar dentate nucleus in chronic neuronopathic GD. GD1 is characterized by astrogliosis without prominent neuronal loss. In GD-LBD, widespread Lewy body pathology is seen, often involving hippocampal regions CA2-4. Additional neuropathological examinations in GD are sorely needed to clarify disease-specific patterns and elucidate causative mechanisms relevant to GD, and potentially to more common neurodegenerative diseases.

Diagnosing neuronopathic Gaucher disease: New considerations and challenges in assigning Gaucher phenotypes.

Gaucher disease (GD), resulting from biallelic mutations in the gene GBA1, is a monogenic recessively inherited Mendelian disorder with a wide range of phenotypic presentations. The more severe forms of the disease, acute neuronopathic GD (GD2) and chronic neuronopathic GD (GD3), also have a continuum of disease severity with an overlap in manifestations and limited genotype-phenotype correlation. In very young patients, assigning a definitive diagnosis can sometimes be challenging. Several recent studies highlight specific features of neuronopathic GD that may provide diagnostic clues. Distinguishing between the different GD types has important therapeutic implications. Currently there are limited treatment options specifically for neuronopathic GD due to the difficulty in delivering therapies across the blood-brain barrier. In this work, we present both classic and newly appreciated aspects of the Gaucher phenotype that can aid in discriminating between acute and chronic neuronopathic GD, and highlight the continuing therapeutic challenges.

Investigation of a dysmorphic facial phenotype in patients with Gaucher disease types 2 and 3.

Gaucher disease (GD) is a rare lysosomal storage disorder that is divided into three subtypes based on presentation of neurological manifestations. Distinguishing between the types has important implications for treatment and counseling. Yet, patients with neuronopathic forms of GD, types 2 and 3, often present at young ages and can have overlapping phenotypes. It has been shown that new technologies employing artificial intelligence and facial recognition software can assist with dysmorphology assessments. Though classically not associated nor previously described with a dysmorphic facial phenotype, this study investigated whether a facial recognition platform could distinguish between photos of patients with GD2 and GD3 and discriminate between them and photos of healthy controls. Each cohort included over 100 photos. A cross validation scheme including a series of binary comparisons between groups was used. Outputs included a composite photo of each cohort and either a receiver operating characteristic curve or a confusion matrix. Binary comparisons showed that the software could correctly group photos at least 89% of the time. Multiclass comparison between GD2, GD3, and healthy controls demonstrated a mean accuracy of 76.6%, compared to a 37.7% chance for random comparison. Both GD2 and GD3 have now been added to the facial recognition platform as established syndromes that can be identified by the algorithm. These results suggest that facial recognition and artificial intelligence, though no substitute for other diagnostic methods, may aid in the recognition of neuronopathic GD. The algorithm, in concert with other clinical features, also appears to distinguish between young patients with GD2 and GD3, suggesting that this tool can help facilitate earlier implementation of appropriate management.

Longitudinal Positron Emission Tomography of Dopamine Synthesis in Subjects with GBA1 Mutations.

Mutations in GBA1, the gene mutated in Gaucher disease, are a common genetic risk factor for Parkinson disease, although the penetrance is low. We performed [18 F]-fluorodopa positron emission tomography studies of 57 homozygous and heterozygous GBA1 mutation carriers (15 with parkinsonism) and 98 controls looking for early indications of dopamine loss using voxelwise analyses to identify group differences in striatal [18 F]-fluorodopa uptake (Ki ). Forty-eight subjects were followed longitudinally. Cross-sectional and longitudinal comparisons of Ki and Ki change found significant effects of Parkinson disease. However, at baseline and over time, striatal [18 F]-fluorodopa uptake in mutation carriers without parkinsonism did not significantly differ from controls. ANN NEUROL 2020;87:652-657.

α-Synuclein Deposition in Sympathetic Nerve Fibers in Genetic Forms of Parkinson's Disease.

BACKGROUND: Cytoplasmic inclusions of α-synuclein (α-syn) in brainstem neurons are characteristic of idiopathic Parkinson's disease (PD). PD also entails α-syn buildup in sympathetic nerves. Among genetic forms of PD, the relative extents of sympathetic intraneuronal accumulation of α-syn have not been reported. OBJECTIVE: This cross-sectional observational study compared magnitudes of intraneuronal deposition of α-syn in common and rare genetic forms of PD. METHODS: α-Syn deposition was quantified by the α-syn-tyrosine hydroxylase colocalization index in C2 cervical skin biopsies from 65 subjects. These included 30 subjects with pathogenic mutations in SNCA (n = 3), PRKN [biallelic (n = 7) and monoallelic (n = 3)], LRRK2 (n = 7), GBA (n = 7), or PARK7/DJ1 [biallelic (n = 1) and monoallelic (n = 2)]. Twenty-five of the mutation carriers had PD and five did not. Data were also analyzed from 19 patients with idiopathic PD and 16 control participants. RESULTS: α-Syn deposition varied as a function of genotype (F = 16.7, P < 0.0001). It was above the control range in 100% of subjects with SNCA mutations, 100% with LRRK2 mutations, 95% with idiopathic PD, 83% with GBA mutations, and 0% with biallelic PRKN mutations. α-Syn deposition in the biallelic PRKN group was significantly higher than in the control group. In addition, patients with biallelic PRKN mutations had higher α-syn deposition than their unaffected siblings. CONCLUSIONS: Individuals with SNCA, DJ-1, LRRK2, or GBA mutations have substantial intraneuronal α-syn deposition in sympathetic noradrenergic nerves in skin biopsies, whereas those with biallelic PRKN mutations do not. Biallelic PRKN patients may have mildly increased α-syn deposition compared with control subjects. © 2021 International Parkinson and Movement Disorder Society.

Behavioral Phenotyping in a Murine Model of GBA1-Associated Parkinson Disease.

Mutations in GBA1, the gene encoding glucocerebrosidase, are common genetic risk factors for Parkinson disease (PD). While the mechanism underlying this relationship is unclear, patients with GBA1-associated PD often have an earlier onset and faster progression than idiopathic PD. Previously, we modeled GBA1-associated PD by crossing gba haploinsufficient mice with mice overexpressing a human mutant α-synuclein transgene (SNCAA53T), observing an earlier demise, shorter life span and faster symptom progression, although behavioral testing was not performed. To assess whether gba+/-//SNCAA53T mice exhibit a prodromal behavioral phenotype, we studied three cardinal PD features: olfactory discrimination, memory dysfunction, and motor function. The longitudinal performance of gba+/-//SNCAA53T (n = 8), SNCAA53T (n = 9), gba+/- (n = 10) and wildtype (n = 6) mice was evaluated between ages 8 and 23 months using the buried pellet test, novel object recognition test and the beam walk. Fifteen-month-old gba+/-//SNCAA53T mice showed more olfactory and motor deficits than wildtype mice. However, differences between gba+/-//SNCAA53T and SNCAA53T mice generally did not reach statistical significance, possibly due to small sample sizes. Furthermore, while gba haploinsufficiency leads to a more rapid demise, this might not result in an earlier prodromal stage, and other factors, including aging, oxidative stress and epigenetics, may contribute to the more fulminant disease course.

C-terminal α-synuclein truncations are linked to cysteine cathepsin activity in Parkinson's disease.

A pathological feature of Parkinson's disease (PD) is Lewy bodies (LBs) composed of α-synuclein (α-syn) amyloid fibrils. α-Syn is a 140 amino acids-long protein, but truncated α-syn is enriched in LBs. The proteolytic processes that generate these truncations are not well-understood. On the basis of our previous work, we propose that these truncations could originate from lysosomal activity attributable to cysteine cathepsins (Cts). Here, using a transgenic SNCAA53T mouse model, overexpressing the PD-associated α-syn variant A53T, we compared levels of α-syn species in purified brain lysosomes from nonsymptomatic mice with those in age-matched symptomatic mice. In the symptomatic mice, antibody epitope mapping revealed enrichment of C-terminal truncations, resulting from CtsB, CtsL, and asparagine endopeptidase. We did not observe changes in individual cathepsin activities, suggesting that the increased levels of C-terminal α-syn truncations are because of the burden of aggregated α-syn. Using LC-MS and purified α-syn, we identified C-terminal truncations corresponding to amino acids 1-122 and 1-90 from the SNCAA53T lysosomes. Feeding rat dopaminergic N27 cells with exogenous α-syn fibrils confirmed that these fragments originate from incomplete fibril degradation in lysosomes. We mimicked these events in situ by asparagine endopeptidase degradation of α-syn fibrils. Importantly, the resulting C-terminally truncated fibrils acted as superior seeds in stimulating α-syn aggregation compared with that of the full-length fibrils. These results unequivocally show that C-terminal α-syn truncations in LBs are linked to Cts activities, promote amyloid formation, and contribute to PD pathogenesis.

A characterization of Gaucher iPS-derived astrocytes: Potential implications for Parkinson's disease.

While astrocytes, the most abundant cells found in the brain, have many diverse functions, their role in the lysosomal storage disorder Gaucher disease (GD) has not been explored. GD, resulting from the inherited deficiency of the enzyme glucocerebrosidase and subsequent accumulation of glucosylceramide and its acylated derivative glucosylsphingosine, has both non-neuronopathic (GD1) and neuronopathic forms (GD2 and 3). Furthermore, mutations in GBA1, the gene mutated in GD, are an important risk factor for Parkinson's disease (PD). To elucidate the role of astrocytes in the disease pathogenesis, we generated iAstrocytes from induced pluripotent stem cells made from fibroblasts taken from controls and patients with GD1, with and without PD. We also made iAstrocytes from an infant with GD2, the most severe and progressive form, manifesting in infancy. Gaucher iAstrocytes appropriately showed deficient glucocerebrosidase activity and levels and substrate accumulation. These cells exhibited varying degrees of astrogliosis, Glial Fibrillary Acidic Protein (GFAP) up-regulation and cellular proliferation, depending on the level of residual glucocerebrosidase activity. Glutamte uptake assays demonstrated that the cells were functionally active, although the glutamine transporter EEAT2 was upregulated and EEAT1 downregulated in the GD2 samples. GD2 iAstrocytes were morphologically different, with severe cytoskeletal hypertrophy, overlapping of astrocyte processes, pronounced up-regulation of GFAP and S100ß, and significant astrocyte proliferation, recapitulating the neuropathology observed in patients with GD2. Although astrocytes do not express α-synuclein, when the iAstrocytes were co-cultured with dopaminergic neurons generated from the same iPSC lines, excessive α-synuclein released from neurons was endocytosed by astrocytes, translocating into lysosomes. Levels of aggregated α-synuclein increased significantly when cells were treated with monomeric or fibrillar α-synuclein. GD1-PD and GD2 iAstrocytes also exhibited impaired Cathepsin D activity, leading to further α-synuclein accumulation. Cytokine and chemokine profiling of the iAstrocytes demonstrated an inflammatory response. Thus, in patients with GBA1-associated parkinsonism, astrocytes appear to play a role in α-synuclein accumulation and processing, contributing to neuroinflammation.

EEG abnormalities in patients with chronic neuronopathic Gaucher disease: A retrospective review.

The clinical phenotype of Gaucher disease type 3 (GD3), a neuronopathic lysosomal storage disorder, encompasses a wide array of neurological manifestations including neuro-ophthalmological findings, developmental delay, and seizures including progressive myoclonic epilepsy. Electroencephalography (EEG) is a widely available tool used to identify abnormalities in cerebral function, as well as epileptiform abnormalities indicating an increased risk of seizures. We characterized the EEG findings in GD3, reviewing 67 patients with 293 EEGs collected over nearly 50 years. Over 93% of patients had some form of EEG abnormality, most consisting of background slowing (90%), followed by interictal epileptiform discharges (IEDs) (54%), and photoparoxysmal responses (25%). The seven patients without background slowing were all under age 14 (mean 6.7 years). There was a history of seizures in 37% of this cohort; only 30% of these had IEDs on EEG. Conversely, only 56% of patients with IEDs had a history of seizures. These observed EEG abnormalities document an important aspect of the natural history of GD3 and could potentially assist in identifying neurological involvement in a patient with subtle clinical findings. Additionally, this comprehensive description of longitudinal EEG data provides essential baseline data for understanding central nervous system involvement in neuronopathic GD.