A PRISMA Scoping Review to Explore Interventions to Prevent Firearm-Related Injury and Suicide in Older Adults.

OBJECTIVES: This scoping review aims to examine existing research into firearm safety interventions designed to prevent firearm injury and suicide in older adults. METHODS: Select databases were searched in 5/2023. Included articles involved an/a 1. aim to develop or investigate firearm safety interventions, 2. focus on adults 50 years and older, and 3. primary analysis. RESULTS: The search yielded 10 articles which primarily focused on firearm safety counseling with older adults with suicide risk or emerging impairment. The review found that older adults may be open to receiving firearm safety counseling but that providers feel ill-equipped to have these conversations and to reliably identify suicide risk. Two studies presented promising data on the impact and acceptability of training providers in a firearm safety intervention. The review also identified the importance of building trust between older patients and providers to have helpful discussions regarding firearms, and highlighted specific approaches that facilitate openness to participate in these exchanges. CONCLUSIONS: Further research into adapting interventions to meet the clinical needs of older adults and treatment efficacy trials is necessary. CLINICAL IMPLICATIONS: Training healthcare providers to conduct firearm safety interventions with older adults may be an acceptable and impactful avenue to prevent suicide.

Neuroinflammation and α-synuclein accumulation in response to glucocerebrosidase deficiency are accompanied by synaptic dysfunction.

Clinical, epidemiological and experimental studies confirm a connection between the common degenerative movement disorder Parkinson's disease (PD) that affects over 1 million individuals, and Gaucher disease, the most prevalent lysosomal storage disorder. Recently, human imaging studies have implicated impaired striatal dopaminergic neurotransmission in early PD pathogenesis in the context of Gaucher disease mutations, but the underlying mechanisms have yet to be characterized. In this report we describe and characterize two novel long-lived transgenic mouse models of Gba deficiency, along with a subchronic conduritol-ß-epoxide (CBE) exposure paradigm. All three murine models revealed striking glial activation within nigrostriatal pathways, accompanied by abnormal α-synuclein accumulation. Importantly, the CBE-induced, pharmacological Gaucher mouse model replicated this change in dopamine neurotransmission, revealing a markedly reduced evoked striatal dopamine release (approximately 2-fold) that indicates synaptic dysfunction. Other changes in synaptic plasticity markers, including microRNA profile and a 24.9% reduction in post-synaptic density size, were concomitant with diminished evoked dopamine release following CBE exposure. These studies afford new insights into the mechanisms underlying the Parkinson's-Gaucher disease connection, and into the physiological impact of related abnormal α-synuclein accumulation and neuroinflammation on nigrostriatal dopaminergic neurotransmission.

In silico and functional studies of the regulation of the glucocerebrosidase gene.

In Gaucher disease (GD), the inherited deficiency of glucocerebrosidase results in the accumulation of glucocerebroside within lysosomes. Although almost 300 mutations in the glucocerebrosidase gene (GBA) have been identified, the ability to predict phenotype from genotype is quite limited. In this study, we sought to examine potential GBA transcriptional regulatory elements for variants that contribute to phenotypic diversity. Specifically, we generated the genomic sequence for the orthologous genomic region ( approximately 39.4kb) encompassing GBA in eight non-human mammals. Computational comparisons of the resulting sequences, using human sequence as the reference, allowed the identification of multi-species conserved sequences (MCSs). Further analyses predicted the presence of two putative clusters of transcriptional regulatory elements upstream and downstream of GBA, containing five and three transcription factor-binding sites (TFBSs), respectively. A firefly luciferase (Fluc) reporter construct containing sequence flanking the GBA gene was used to test the functional consequences of altering these conserved sequences. The predicted TFBSs were individually altered by targeted mutagenesis, resulting in enhanced Fluc expression for one site and decreased expression for seven others sites. Gel-shift assays confirmed the loss of nuclear-protein binding for several of the mutated constructs. These identified conserved non-coding sequences flanking GBA could play a role in the transcriptional regulation of the gene contributing to the complexity underlying the phenotypic diversity seen in GD.

Lysosomal storage disorders in the newborn.

Lysosomal storage disorders are rare inborn errors of metabolism, with a combined incidence of 1 in 1500 to 7000 live births. These relatively rare disorders are seldom considered when evaluating a sick newborn. A significant number of the >50 different lysosomal storage disorders, however, do manifest in the neonatal period and should be part of the differential diagnosis of several perinatal phenotypes. We review the earliest clinical features, diagnostic tests, and treatment options for lysosomal storage disorders that can present in the newborn. Although many of the lysosomal storage disorders are characterized by a range in phenotypes, the focus of this review is on the specific symptoms and clinical findings that present in the perinatal period, including neurologic, respiratory, endocrine, and cardiovascular manifestations, dysmorphic features, hepatosplenomegaly, skin or ocular involvement, and hydrops fetalis/congenital ascites. A greater awareness of these features may help to reduce misdiagnosis and promote the early detection of lysosomal storage disorders. Implementing therapy at the earliest stage possible is crucial for several of the lysosomal storage disorders; hence, an early appreciation of these disorders by physicians who treat newborns is essential.

Optimization and validation of two miniaturized glucocerebrosidase enzyme assays for high throughput screening.

Glucocerebrosidase (GC) catalyzes the hydrolysis of beta-glucocerebroside to glucose and ceramide in lysosomes. Mutations in the glucocerebrosidase gene (GBA) result in Gaucher disease, an autosomal recessive lysosomal storage disorder. Many of the mutations encountered in patients with Gaucher disease are missense alterations that may cause misfolding, decreased stability and/or mistrafficking of this lysosomal protein. Some inhibitors of GC have been shown to act as chemical chaperones, stabilizing the conformation of mutant proteins and thus restoring their function. High throughput screening (HTS) of small molecule libraries for such compounds with potential for chaperone therapy requires an accurate, reproducible and sensitive assay method. We have adapted and optimized two fluorogenic GC enzyme assays and miniaturized them into the 1536-well plate format for HTS. The two substrates, 4-methylumbelliferyl beta-D-glucopyranoside and resorufin beta-D-glucopyranoside, have K(m) values of 768 microM and 33 microM, respectively, and different emission spectra. Paired screening with the two assays helps to eliminate false inference of activity due to autofluorescence or fluorescence quenching by the screened compounds. Test screens with the LOPAC library indicated that both assays were robust for HTS, and gave comparable results for GC inhibitor activities. These two assays can be used to identify both GC activators and inhibitors with potential therapeutic value.

Gaucher disease: mutation and polymorphism spectrum in the glucocerebrosidase gene (GBA).

Gaucher disease (GD) is an autosomal recessive disorder caused by the deficiency of glucocerebrosidase, a lysosomal enzyme that catalyses the hydrolysis of the glycolipid glucocerebroside to ceramide and glucose. Lysosomal storage of the substrate in cells of the reticuloendothelial system leads to multisystemic manifestations, including involvement of the liver, spleen, bone marrow, lungs, and nervous system. Patients with GD have highly variable presentations and symptoms that, in many cases, do not correlate well with specific genotypes. Almost 300 unique mutations have been reported in the glucocerebrosidase gene (GBA), with a distribution that spans the gene. These include 203 missense mutations, 18 nonsense mutations, 36 small insertions or deletions that lead to either frameshifts or in-frame alterations, 14 splice junction mutations, and 13 complex alleles carrying two or more mutations in cis. Recombination events with a highly homologous pseudogene downstream of the GBA locus also have been identified, resulting from gene conversion, fusion, or duplication. In this review we discuss the spectrum of GBA mutations and their distribution in the patient population, evolutionary conservation, clinical presentations, and how they may affect the structure and function of glucocerebrosidase.

Three classes of glucocerebrosidase inhibitors identified by quantitative high-throughput screening are chaperone leads for Gaucher disease.

Gaucher disease is an autosomal recessive lysosomal storage disorder caused by mutations in the glucocerebrosidase gene. Missense mutations result in reduced enzyme activity that may be due to misfolding, raising the possibility of small-molecule chaperone correction of the defect. Screening large compound libraries by quantitative high-throughput screening (qHTS) provides comprehensive information on the potency, efficacy, and structure-activity relationships (SAR) of active compounds directly from the primary screen, facilitating identification of leads for medicinal chemistry optimization. We used qHTS to rapidly identify three structural series of potent, selective, nonsugar glucocerebrosidase inhibitors. The three structural classes had excellent potencies and efficacies and, importantly, high selectivity against closely related hydrolases. Preliminary SAR data were used to select compounds with high activity in both enzyme and cell-based assays. Compounds from two of these structural series increased N370S mutant glucocerebrosidase activity by 40-90% in patient cell lines and enhanced lysosomal colocalization, indicating chaperone activity. These small molecules have potential as leads for chaperone therapy for Gaucher disease, and this paradigm promises to accelerate the development of leads for other rare genetic disorders.

Glucocerebrosidase mutations in Chinese subjects from Taiwan with sporadic Parkinson disease.

BACKGROUND: An association between glucocerebrosidase, the enzyme deficient in Gaucher disease, and the synucleinopathies has been suggested both by the development of parkinsonism in Gaucher probands and carriers, as well as by the presence of mutations in the gene for glucocerebrosidase (GBA) in different series of subjects with synucleinopathies. In this study, an open access Parkinson repository was used to establish the incidence of GBA alterations in a different ethnic cohort with sporadic Parkinson disease (PD). METHODS: The glucocerebrosidase gene was sequenced in samples collected from 92 Chinese Parkinson disease patients from Taiwan along with 92 clinically screened controls, matched for age and ethnicity. FINDINGS: The frequency of GBA mutations among the Chinese PD probands was 4.3%, in contrast to 1.1% in Chinese controls. Mutant alleles identified included two known mutations, L444P and D409H, and two novel mutations, L174P and Q497R. INTERPRETATION: These results, ascertained in subjects from Taiwan collected in a standardized and clinically rigorous open access Parkinson disease repository and screened by direct sequencing of GBA, demonstrate that GBA mutations are also encountered in Chinese subjects with sporadic PD at a higher frequency than many other known PD genes. The study demonstrates that the association of GBA mutations with the development of parkinsonian pathology is not related to ethnic origin.

Therapy for Gaucher disease: don't stop thinking about tomorrow.

While enzyme replacement therapy for Gaucher disease has been widely used and appears to be an efficacious and safe treatment, this success should not be a reason for complacency. Other treatment strategies currently under consideration for patients with Gaucher disease include gene therapy, substrate reduction therapy and chaperone therapy. Furthermore, improvements in enzyme therapy could also have a significant clinical impact. Individuals with Gaucher disease and other lysosomal disorders will greatly benefit from continual refinement and optimization of the current therapy, as well as from the development of new treatment modalities that offer improvements in efficacy, cost, safety and availability.

Gaucher mutation N188S is associated with myoclonic epilepsy.

The recent article by Montfort et al. [2004] reported a functional analysis of 13 glucocerebrosidase alleles, including mutation N188S, which they considered to be a "very mild mutation" or "modifier variant." Our clinical experience with patients carrying this mutation and preliminary protein modeling data lead us to dispute this conclusion.

A novel alteration in metaxin 1, F202L, is associated with N370S in Gaucher disease.

The gene for glucocerebrosidase ( GBA), the enzyme deficient in Gaucher disease, is located in a gene-rich region on 1q21. Metaxin 1( MTX1) is a convergently transcribed gene contiguous to the 3' end of the GBA pseudogene. A single nucleotide alteration in MTX1, 628T-->C, resulting in the amino acid change F202L, was identified in patients with Gaucher disease in association with the common N370S mutation in GBA. The polymorphism was also present on 4.6% of 152 control alleles, but could have functional consequences that have a modifying role in Gaucher disease.

Glucocerebrosidase mutations in subjects with parkinsonism.

Recent studies showing an association between glucocerebrosidase deficiency and parkinsonism in Gaucher disease prompted an examination of the glucocerebrosidase gene sequence (GBA) and enzyme activity in brain samples from 57 subjects carrying the diagnosis of Parkinson disease. Alterations in GBA were identified in 12 samples (21%) and were more frequent among the younger subjects. These included eight with mutations (N370S, L444P, K198T, and R329C) and four with probable polymorphisms (T369M and E326K). Our findings suggest that mutations in glucocerebrosidase may be a risk factor for the development of parkinsonism.

Myoclonic epilepsy in Gaucher disease: genotype-phenotype insights from a rare patient subgroup.

Gaucher disease, the inherited deficiency of lysosomal glucocerebrosidase, presents with a wide spectrum of manifestations. Although Gaucher disease has been divided into three clinical types, patients with atypical presentations continue to be recognized. A careful phenotypic and genotypic assessment of patients with unusual symptoms may help define factors that modify phenotype in this disorder. One such example is a rare subgroup of patients with type 3 Gaucher disease who develop progressive myoclonic epilepsy. We evaluated 16 patients with myoclonic epilepsy, nine of whom were diagnosed by age 4 y with severe visceral involvement and myoclonus, and seven with a more chronic course, who were studied between ages 22 and 40. All of the patients had abnormal horizontal saccadic eye movements. Fourteen different genotypes were encountered, yet there were several shared alleles, including V394L (seen on two alleles), G377S (seen on three alleles), and L444P, N188S, and recombinant alleles (each found on four alleles). V394L, G377S, and N188S are mutations that have previously been associated with non-neuronopathic Gaucher disease. The spectrum of genotypes differed significantly from other patients with type 3 Gaucher disease, where genotypes L444P/L444P and R463C/null allele predominated. Northern blot studies revealed a normal glucocerebrosidase transcript, whereas Western studies showed that the patients studied lacked the processed 56 kD isoform of the enzyme, consistent with neuronopathic Gaucher disease. Brain autopsy samples from two patients demonstrated elevated levels of glucosylsphingosine, a toxic glycolipid, which could contribute to the development of myoclonus. Thus, although there were certain shared mutant alleles found in these patients, both the lack of a shared genotype and the variability in clinical presentations suggest that other modifiers must contribute to this rare phenotype.

Reciprocal and nonreciprocal recombination at the glucocerebrosidase gene region: implications for complexity in Gaucher disease.

Gaucher disease results from an autosomal recessive deficiency of the lysosomal enzyme glucocerebrosidase. The glucocerebrosidase gene is located in a gene-rich region of 1q21 that contains six genes and two pseudogenes within 75 kb. The presence of contiguous, highly homologous pseudogenes for both glucocerebrosidase and metaxin at the locus increases the likelihood of DNA rearrangements in this region. These recombinations can complicate genotyping in patients with Gaucher disease and contribute to the difficulty in interpreting genotype-phenotype correlations in this disorder. In the present study, DNA samples from 240 patients with Gaucher disease were examined using several complementary approaches to identify and characterize recombinant alleles, including direct sequencing, long-template polymerase chain reaction, polymorphic microsatellite repeats, and Southern blots. Among the 480 alleles studied, 59 recombinant alleles were identified, including 34 gene conversions, 18 fusions, and 7 downstream duplications. Twenty-two percent of the patients evaluated had at least one recombinant allele. Twenty-six recombinant alleles were found among 310 alleles from patients with type 1 disease, 18 among 74 alleles from patients with type 2 disease, and 15 among 96 alleles from patients with type 3 disease. Several patients carried two recombinations or mutations on the same allele. Generally, alleles resulting from nonreciprocal recombination (gene conversion) could be distinguished from those arising by reciprocal recombination (crossover and exchange), and the length of the converted sequence was determined. Homozygosity for a recombinant allele was associated with early lethality. Ten different sites of crossover and a shared pentamer motif sequence (CACCA) that could be a hotspot for recombination were identified. These findings contribute to a better understanding of genotype-phenotype relationships in Gaucher disease and may provide insights into the mechanisms of DNA rearrangement in other disorders.

Glucosylsphingosine accumulation in tissues from patients with Gaucher disease: correlation with phenotype and genotype.

Gaucher disease, the inherited deficiency of lysosomal glucocerebrosidase, presents with a wide spectrum of clinical manifestations including neuronopathic and non-neuronopathic forms. While the lipid glucosylceramide is stored in both patients with Gaucher disease and in a null allele mouse model of Gaucher disease, elevated levels of a second potentially toxic substrate, glucosylsphingosine, are also found. Using high performance liquid chromatography, glucosylsphingosine levels were measured in tissues from patients with type 1, 2, and 3 Gaucher disease. Glucosylsphingosine was measured in 16 spleen samples (8 type 1; 4 type 2; and 4, type 3) and levels ranged from 54 to 728 ng/mg protein in the patients with type 1 disease, 133 to 1200 ng/mg protein in the patients with type 2, and 109 to 1298 ng/mg protein in the type 3 samples. The levels of splenic glucosylsphingosine bore no relation to the type of Gaucher disease, the age of the patient, the genotype, nor the clinical course. In the same patients, hepatic glucosylsphingosine levels were lower than in spleen. Glucosylsphingosine was also measured in brains from 13 patients (1 type 1; 8 type 2; and 4 type 3). While the glucosylsphingosine level in the brain from the type 1 patient, 1.0 ng/mg protein, was in the normal range, the levels in the type 3 samples ranged from 14 to 32 ng/mg protein, and in the type 2 samples from 24 to 437 ng/mg protein, with the highest values detected in two fetuses with hydrops fetalis. The elevated levels found in brains from patients with neuronopathic Gaucher disease support the hypothesis that glucosylsphingosine may contribute to the nervous system involvement in these patients.