Background: Gaucher disease (GD) is a lysosomal storage disorder caused by mutations in the GBA1 gene, leading to β-glucocerebrosidase deficiency and glucosylceramide accumulation. Methods: We analyzed short- and long-term dynamics of lyso-glucosylceramide (lyso-Gb1) in a large cohort of GD patients undergoing enzyme replacement therapy (ERT). Results: Eight-years analysis of lyso-Gb1 revealed statistically insignificant variability in the biomarker across the years and relatively high individual variability in patients\' results. GD type 1 (GD1) patients exhibited higher variability compared to GD type 3 (GD3) patients (coefficients of variation: 34% and 23%, respectively; p-value = 0.0003). We also investigated the short-term response of the biomarker to enzyme replacement therapy (ERT), measuring lyso-Gb1 right before and 30 min after treatment administration. We tested 20 GD patients (16 GD1, 4 GD3) and observed a rapid and significant reduction in lyso-Gb1 levels (average decrease of 17%; p-value < 0.0001). This immediate response reaffirms the efficacy of ERT in reducing substrate accumulation in GD patients but, on the other hand, suggests the biomarker\'s instability between the infusions. Conclusions: These findings underscore lyso-Gb1\'s potential as a reliable biomarker for monitoring efficacy of treatment. However, individual variability and dry blood spot (DBS) testing limitations urge a further refinement in clinical application. Our study contributes valuable insights into GD patient management, emphasizing the evolving role of biomarkers in personalized medicine.

Skeletal anomalies represent a characteristic feature of type 1 Gaucher disease (GD1). Here we evaluated the impact of an integrated therapy comprising enzyme-replacement therapy (ERT), cholecalciferol, and a normocalcemic-normocaloric-hyposodic diet (bone diet) on bone health in GD1 patients. We also performed a systematic review to compare our results with available data. From January 1, 2015 to February 28, 2019, all GD1 patients referred to Federico II University were enrolled and treated with the integrated therapy. Bone turnover markers and bone mineral density (BMD) were evaluated at baseline (T0) and after 24 months (T24). We enrolled 25 GD1 patients, all showing 25-hydroxy vitamin D (25OHD) levels < 50 nmol/l (hypovitaminosis D) at T0. Response to cholecalciferol treatment was effective, showing a direct relationship between 25OHD levels before and after treatment. At T0, 2 GD1 patients showed fragility fractures, 5 the Erlenmeyer flask deformity, 3 osteonecrosis, and 7 a BMD Z-score ≤ -2. Overall, GD1 patients with bone anomalies showed higher C-terminal telopeptide levels compared with those without bone anomalies. No new bone anomalies occurred during 2 years of follow-up. At T24, BMD remained stable across the entire study cohort, including in patients with bone anomalies. The systematic review showed that our study is the first that evaluated all bone health parameters. Hypovitaminosis D is prevalent in GD1 patients. The response to cholecalciferol treatment was effective but different to healthy subjects and in patients with metabolic bone disorders. Integrated therapy including ERT, cholecalciferol, and bone diet guarantees bone health.

People with rare lysosomal storage diseases face challenges in their care that arise from disease complexity and heterogeneity, compounded by many healthcare professionals being unfamiliar with these diseases. These challenges can result in long diagnostic journeys and inadequate care. Over 30 years ago, the Rare Disease Registries for Gaucher, Fabry, Mucopolysaccharidosis type I and Pompe diseases were established to address knowledge gaps in disease natural history, clinical manifestations of disease and treatment outcomes. Evidence generated from the real-world data collected in these registries supports multiple stakeholders, including patients, healthcare providers, drug developers, researchers and regulators. To maximise the impact of real-world evidence from these registries, engagement and collaboration with the patient communities is essential. To this end, the Rare Disease Registries Patient Council was established in 2019 as a partnership between the Rare Disease Registries and global and local patient advocacy groups to share perspectives on how registry data are used and disseminated. The Patient Council has resulted in a number of patient initiatives including patient representation at Rare Disease Registries advisory boards; development of plain language summaries of registry publications to increase availability of real-world evidence to patient communities; and implementation of digital innovations such as electronic patient-reported outcomes, and patient-facing registry reports and electronic consent (in development), all to enhance patient engagement. The Patient Council is building on the foundations of industry-patient advocacy group collaboration to fully integrate patient communities in decision-making and co-create solutions for the rare disease community.

Hearing loss is frequently associated with Gaucher disease (GD). Gaucher cells are enlarged reticuloendothelial cells containing glucocerebroside in the lysosomes due to deficiency of the glucocerebrosidase. Gaucheromas consist of accumulated Gaucher cells. Gaucher cells accumulate in variable tissues including the liver, spleen, bone marrow, and the middle ear and the mastoid causing conductive hearing loss. Neurons and astrocytes in the central nervous system are affected in neuronopathic GD leading to sensorineural hearing loss. Gaucheromas can develop even in patients treated with enzyme replacement therapy (ERT). We report a 19-year-old female patient with GD type 3 who developed profound bilateral hearing loss associated with intracranial Gaucheroma. Combination therapy of ERT with imiglucerase and substrate reduction therapy (SRT) with eliglustat significantly decreased the size of Gaucher cells and cleared the characteristic microtubular structures in the lysosomes in Gaucher cells. Early implementation of SRT may prevent at least conductive hearing impairment in GD although it may not prevent sensorineural hearing loss due to inner hair cell dysfunction which is also known to be associated with neuronopathic GD.

Background: Long-term patient registries are important for evaluating treatment outcomes in patients with rare diseases, and can provide insights into natural disease history and progression in real-world clinical practice. Initiated in 2010, the Gaucher Outcome Survey (GOS) is an ongoing, international, multicenter, observational registry (ClinicalTrials.gov Identifier: NCT03291223) for patients with a diagnosis of Gaucher disease (GD), irrespective of treatment type or status, with a primary objective to monitor safety and long-term effectiveness of velaglucerase alfa. Methods: Here, we evaluated the GOS population 12 years after the registry initiation. Results: As of 25 February 2023, 2084 patients enrolled in the GOS and 1643 received GD-specific treatment. Patients exhibited broad heterogeneity at baseline: age of diagnosis (0 to 85.3 years), hemoglobin concentrations (<80.0 g/L to >150 g/L), platelet counts (<50 × 109/L to >450 × 109/L), and liver and spleen volumes. Most patients treated with enzyme replacement therapy or substrate reduction therapy reported improvements in clinical parameters within 1 year of treatment initiation, maintained over the course of treatment up to 12 years, whereas untreated patients had baseline values closer to standard reference thresholds and showed stability over time. Conclusion: The 12-year data from the GOS confirm the impact of long-term treatment with GD-specific agents and offer insights into disease progression and outcomes in a real-world setting.

Pulmonologists may be involved in managing pulmonary diseases in children with complex clinical pictures without a diagnosis. Moreover, they are routinely involved in the multidisciplinary care of children with rare diseases, at baseline and during follow-up, for lung function monitoring. Lysosomal storage diseases (LSDs) are a group of genetic diseases characterised by a specific lysosomal enzyme deficiency. Despite varying pathogen and organ involvement, they are linked by the pathological accumulation of exceeding substrates, leading to cellular toxicity and subsequent organ damage. Less severe forms of LSDs can manifest during childhood or later in life, sometimes being underdiagnosed. Respiratory impairment may stem from different pathogenetic mechanisms, depending on substrate storage in bones, with skeletal deformity and restrictive pattern, in bronchi, with obstructive pattern, in lung interstitium, with altered alveolar gas exchange, and in muscles, with hypotonia. This narrative review aims to outline different pulmonary clinical findings and a diagnostic approach based on key elements for differential diagnosis in some treatable LSDs like Gaucher disease, Acid Sphingomyelinase deficiency, Pompe disease and Mucopolysaccharidosis. Alongside their respiratory clinical aspects, which might overlap, we will describe radiological findings, lung functional patterns and associated symptoms to guide pediatric pulmonologists in differential diagnosis. The second part of the paper will address follow-up and management specifics. Recent evidence suggests that new therapeutic strategies play a substantial role in preventing lung involvement in early-treated patients and enhancing lung function and radiological signs in others. Timely diagnosis, driven by clinical suspicion and diagnostic workup, can help in treating LSDs effectively.

The liver, given its role as the central metabolic organ, is involved in many inherited metabolic disorders, including lysosomal storage diseases (LSDs). The aim of this manuscript was to provide a comprehensive overview on liver involvement in LSDs, focusing on clinical manifestation and its pathomechanisms. Gaucher disease, acid sphingomyelinase deficiency, and lysosomal acid lipase deficiency were thoroughly reviewed, with hepatic manifestation being a dominant clinical phenotype. The natural history of liver disease in the above-mentioned lysosomal disorders was delineated. The importance of Niemann-Pick type C disease as a cause of cholestatic jaundice, preceding neurological manifestation, was also highlighted. Diagnostic methods and current therapeutic management of LSDs were also discussed in the context of liver involvement.

Glucocerebrosidase (GCase) is a lysosomal enzyme that catalyzes the breakdown of glucosylceramide in the presence of its activator saposin C (SapC). SapC arises from the proteolytical cleavage of prosaposin (encoded by PSAP gene), which gives rise to four saposins. GCase is targeted to the lysosomes by LIMP-2, encoded by SCARB2 gene. GCase deficiency causes Gaucher Disease (GD), which is mainly due to biallelic pathogenetic variants in the GCase-encoding gene, GBA1. However, impairment of GCase activity can be rarely caused by SapC or LIMP-2 deficiencies. We report a new case of LIMP-2 deficiency and a new case of SapC deficiency (missing all four saposins, PSAP deficiency), and measured common biomarkers of GD and GCase activity. Glucosylsphingosine and chitotriosidase activity in plasma were increased in GCase deficiencies caused by PSAP and GBA1 mutations, whereas SCARB2-linked deficiency showed only Glucosylsphingosine elevation. GCase activity was reduced in fibroblasts and leukocytes: the decrease was sharper in GBA1- and SCARB2-mutant fibroblasts than PSAP-mutant ones; LIMP-2-deficient leukocytes displayed higher residual GCase activity than GBA1-mutant ones. Finally, we demonstrated that GCase mainly undergoes proteasomal degradation in LIMP-2-deficient fibroblasts and lysosomal degradation in PSAP-deficient fibroblasts. Thus, we analyzed the differential biochemical profile of GCase deficiencies due to the ultra-rare PSAP and SCARB2 biallelic pathogenic variants in comparison with the profile observed in GBA1-linked GCase deficiency.

Mutations in GBA1 cause Gaucher disease and are the most important genetic risk factor for Parkinson\'s disease. However, analysis of transcription at this locus is complicated by its highly homologous pseudogene, GBAP1. We show that >50% of short RNA-sequencing reads mapping to GBA1 also map to GBAP1. Thus, we used long-read RNA sequencing in the human brain, which allowed us to accurately quantify expression from both GBA1 and GBAP1. We discovered significant differences in expression compared to short-read data and identify currently unannotated transcripts of both GBA1 and GBAP1. These included protein-coding transcripts from both genes that were translated in human brain, but without the known lysosomal function-yet accounting for almost a third of transcription. Analyzing brain-specific cell types using long-read and single-nucleus RNA sequencing revealed region-specific variations in transcript expression. Overall, these findings suggest nonlysosomal roles for GBA1 and GBAP1 with implications for our understanding of the role of GBA1 in health and disease.

Background/Objectives: Gaucher Disease type 1 (GD1) is a recessively inherited lysosomal storage disorder caused by a deficiency in the enzyme β-glucocerebrosidase. Enzyme replacement therapy (ERT) has become the standard of care for patients with GD. However, over 10% of patients experience an incomplete response or partial loss of response to ERT, necessitating the exploration of alternative approaches to enhance treatment outcomes. The present feasibility study aimed to determine the feasibility of using a second-generation artificial intelligence (AI) system that introduces variability into dosing regimens for ERT to improve the response to treatment and potentially overcome the partial loss of response to the enzyme. Methods: This was an open-label, prospective, single-center proof-of-concept study. Five patients with GD1 who received ERT were enrolled. The study used the Altus Care™ cellular-phone-based application, which incorporated an algorithm-based approach to offer random dosing regimens within a pre-defined range set by the physician. The app enabled personalized therapeutic regimens with variations in dosages and administration times. Results: The second-generation AI-based personalized regimen was associated with stable responses to ERT in patients with GD1. The SF-36 quality of life scores improved in one patient, and the sense of change in health improved in two; platelet levels increased in two patients, and hemoglobin remained stable. The system demonstrated a high engagement rate among patients and caregivers, showing compliance with the treatment regimen. Conclusions: This feasibility study highlights the potential of using variability-based regimens to enhance ERT effectiveness in GD and calls for further and longer trials to validate these findings.