Deep learning-based quantification of osteonecrosis using magnetic resonance images in Gaucher disease.

Gaucher disease is one of the most common lysosomal storage disorders. Osteonecrosis is a principal clinical manifestation of Gaucher disease and often leads to joint collapse and fractures. T1-weighted (T1w) modality in MRI is widely used to monitor bone involvement in Gaucher disease and to diagnose osteonecrosis. However, objective and quantitative methods for characterizing osteonecrosis are still limited. In this work, we present a deep learning-based quantification approach for the segmentation of osteonecrosis and the extraction of characteristic parameters. We first constructed two independent U-net models to segment the osteonecrosis and bone marrow unaffected by osteonecrosis (UBM) in spine and femur respectively, based on T1w images from patients in the UK national Gaucherite study database. We manually delineated parcellation maps including osteonecrosis and UBM from 364 T1w images (176 for spine, 188 for femur) as the training datasets, and the trained models were subsequently applied to all the 917 T1w images in the database. To quantify the segmentation, we calculated morphological parameters including the volume of osteonecrosis, the volume of UBM, and the fraction of total marrow occupied by osteonecrosis. Then, we examined the correlation between calculated features and the bone marrow burden score for marrow infiltration of the corresponding image, and no strong correlation was found. In addition, we analyzed the influence of splenectomy and the interval between the age at first symptom and the age of onset of treatment on the quantitative measurements of osteonecrosis. The results are consistent with previous studies, showing that prior splenectomy is closely associated with the fractional volume of osteonecrosis, and there is a positive relationship between the duration of untreated disease and the quantifications of osteonecrosis. We propose this technique as an efficient and reliable tool for assessing the extent of osteonecrosis in MR images of patients and improving prediction of clinically important adverse events.

An increase in ER stress and unfolded protein response in iPSCs-derived neuronal cells from neuronopathic Gaucher disease patients.

Gaucher disease (GD) is a lysosomal storage disorder caused by a mutation in the GBA1 gene, responsible for encoding the enzyme Glucocerebrosidase (GCase). Although neuronal death and neuroinflammation have been observed in the brains of individuals with neuronopathic Gaucher disease (nGD), the exact mechanism underlying neurodegeneration in nGD remains unclear. In this study, we used two induced pluripotent stem cells (iPSCs)-derived neuronal cell lines acquired from two type-3 GD patients (GD3-1 and GD3-2) to investigate the mechanisms underlying nGD by biochemical analyses. These iPSCs-derived neuronal cells from GD3-1 and GD3-2 exhibit an impairment in endoplasmic reticulum (ER) calcium homeostasis and an increase in unfolded protein response markers (BiP and CHOP), indicating the presence of ER stress in nGD. A significant increase in the BAX/BCL-2 ratio and an increase in Annexin V-positive cells demonstrate a notable increase in apoptotic cell death in GD iPSCs-derived neurons, suggesting downstream signaling after an increase in the unfolded protein response. Our study involves the establishment of iPSCs-derived neuronal models for GD and proposes a possible mechanism underlying nGD. This mechanism involves the activation of ER stress and the unfolded protein response, ultimately leading to apoptotic cell death in neurons.

Gaucher Disease: A First Reported Adult Case in Indonesia.

A 44-year-old female presented with a distended abdomen and fatigue. On physical examination, prominent splenomegaly was found. The laboratory investigations revealed pancytopenia and decreased albumin-globulin ratio. The abdominal ultrasonography revealed splenomegaly, cholelithiasis, and cystitis, and the bone survey showed osteopenia. Differential diagnoses included leukemia, multiple myeloma, and myelofibrosis therefore bone marrow puncture was performed. However, histopathologic examination found Gaucher-like cells in the bone marrow aspiration. The finding of CD68 positivity in Gaucher-like cells by using the immunohistochemistry staining supporting Gaucher disease. To confirm the diagnosis, an examination of glucocerebroside substrate from the patient's blood plasma was performed. Glucosylsphingosine, a deacylated form of glucosylceramide, was markedly elevated. Therefore, the diagnosis of Gaucher disease was confirmed. This is the first reported adult Gaucher case diagnosed in Indonesia.

Glucosylceramide accumulation in microglia triggers STING-dependent neuroinflammation and neurodegeneration in mice.

Mutations in the gene encoding the lysosomal enzyme glucocerebrosidase (GCase) are responsible for Gaucher disease (GD) and are considered the strongest genetic risk factor for Parkinson's disease (PD) and Lewy body dementia (LBD). GCase deficiency leads to extensive accumulation of glucosylceramides (GCs) in cells and contributes to the neuropathology of GD, PD, and LBD by triggering chronic neuroinflammation. Here, we investigated the mechanisms by which GC accumulation induces neuroinflammation. We found that GC accumulation within microglia induced by pharmacological inhibition of GCase triggered STING-dependent inflammation, which contributed to neuronal loss both in vitro and in vivo. GC accumulation in microglia induced mitochondrial DNA (mtDNA) leakage to the cytosol to trigger STING-dependent inflammation. Rapamycin, a compound that promotes lysosomal activity, improved mitochondrial function, thereby decreasing STING signaling. Furthermore, lysosomal damage caused by GC accumulation led to defects in the degradation of activated STING, further exacerbating inflammation mediated by microglia. Thus, limiting STING activity may be a strategy to suppress neuroinflammation caused by GCase deficiency.

Rapid and long-lasting efficacy of high-dose ambroxol therapy for neuronopathic Gaucher disease: A case report and literature review.

Gaucher disease (GD) is a lysosomal storage disorder caused by a deficiency in the GBA1-encoded enzyme, ß-glucocerebrosidase. Enzyme replacement therapy is ineffective for neuronopathic Gaucher disease (nGD). High-dose ambroxol has been administered as an alternative treatment for a group of patients with nGD. However, little is known about the clinical indication and the long-term outcome of patients after ambroxol therapy. We herein report a case of a female patient who presented with a progressive disease of GD type 2 from 11 months of age and had the pathogenic variants of p.L483P (formerly defined as p.L444P) and p.R502H (p.R463H) in GBA1. A combined treatment of imiglucerase with ambroxol started improving the patient's motor activity in 1 week, while it kept the long-lasting effect of preventing the deteriorating phenotype for 30 months. A literature review identified 40 patients with nGD, who had received high-dose ambroxol therapy. More than 65% of these patients favorably responded to the molecular chaperone therapy, irrespective of p.L483P homozygous, heterozygous or the other genotypes. These results highlight the long-lasting effect of ambroxol-based chaperone therapy for patients with an expanding spectrum of mutations in GBA1.

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.

Seeing beyond Gaucher disease: Early detection and treatment of ocular complications.

Background: Gaucher disease is a rare genetic disorder caused by a deficiency in the enzyme glucocerebrosidase, which impairs the body's ability to break down certain fats. This leads to the accumulation of glucosyl sphingosine and glucosyl ceramide in the liver, spleen, and bone marrow. Gaucher disease has two major types: nonneuropathic (Type 1) and neuropathic (Type 2 and Type 3). Gaucher disease can have various ophthalmologic manifestations, particularly in Type 3, including posterior segment abnormalities, such as vitreous opacities, condensations, and/or preretinal white dots. We present a case of a patient with Gaucher disease Type 3 who had severe bilateral vitreous and extensive retinal deposits, leading to challenges during surgery. Purpose: This video reports surgical outcomes for an uncommon ophthalmologic manifestation in a patient with Gaucher disease Type 3. We focus on the challenges and results of surgery for severe bilateral vitreous and extensive retinal deposits. Synopsis: A 16-year-old female patient with a history of Gaucher's disease since birth presented with a one-year history of blurred vision in both eyes. Her best-corrected visual acuity was 20/200 in the right eye and 20/100 in the left eye, as measured by Snellen's chart. Intraocular pressure was normal in both eyes, and anterior segment examinations were unremarkable. However, fundus evaluation revealed extensive vitreous deposits that obscured the details of the fundus. Additionally, an epiretinal membrane was observed over the macula in both eyes. Optical coherence tomography (OCT) confirmed the presence of deposits in the vitreous cavity and on the surface of the retina. The patient underwent pars plana vitrectomy with epiretinal membrane removal. A transconjunctival 23-G pars plana vitrectomy was performed to the extent possible. Multiple instruments were used to remove the fluffy vitreous deposits, as they were extremely adherent to the underlying surface of the retina, and brilliant blue dye was used to stain the internal limiting membrane. The epiretinal membrane and internal limiting membrane were removed from the macular area, and the entire cassette fluid was sent for histopathological examination to identify Gaucher cells. At one week postoperative, the patient's visual acuity improved to 20/125 in the right eye, and the fundus picture showed a cleared macular area. OCT showed a reduction in deposits over the retina. The histopathological examination revealed crumpled, barrel-like cytoplasm with an oval nucleus in a hemorrhagic background, suggestive of Gaucher cells. Highlights: Early detection and treatment of ocular manifestations of Gaucher's disease are important to prevent permanent damage to vision. An ophthalmological assessment involving a dilated fundus examination and optical coherence tomography can facilitate early diagnosis and follow-up of ocular manifestations. Timely surgery may be required to preserve functional vision in patients with severe ocular disease. Video Link: https://youtu.be/KR-kfgfDoqM.

Exploring the Pathophysiologic Cascade Leading to Osteoclastogenic Activation in Gaucher Disease Monocytes Generated via CRISPR/Cas9 Technology.

Gaucher disease (GD) is caused by biallelic pathogenic variants in the acid ß-glucosidase gene (GBA1), leading to a deficiency in the ß-glucocerebrosidase (GCase) enzyme activity resulting in the intracellular accumulation of sphingolipids. Skeletal alterations are one of the most disabling features in GD patients. Although both defective bone formation and increased bone resorption due to osteoblast and osteoclast dysfunction contribute to GD bone pathology, the molecular bases are not fully understood, and bone disease is not completely resolved with currently available specific therapies. For this reason, using editing technology, our group has developed a reliable, isogenic, and easy-to-handle cellular model of GD monocytes (GBAKO-THP1) to facilitate GD pathophysiology studies and high-throughput drug screenings. In this work, we further characterized the model showing an increase in proinflammatory cytokines (Interleukin-1ß and Tumor Necrosis Factor-α) release and activation of osteoclastogenesis. Furthermore, our data suggest that GD monocytes would display an increased osteoclastogenic potential, independent of their interaction with the GD microenvironment or other GD cells. Both proinflammatory cytokine production and osteoclastogenesis were restored at least, in part, by treating cells with the recombinant human GCase, a substrate synthase inhibitor, a pharmacological chaperone, and an anti-inflammatory compound. Besides confirming that this model would be suitable to perform high-throughput screening of therapeutic molecules that act via different mechanisms and on different phenotypic features, our data provided insights into the pathogenic cascade, leading to osteoclastogenesis exacerbation and its contribution to bone pathology in GD.

Alpha-Synuclein mRNA Level Found Dependent on L444P Variant in Carriers and Gaucher Disease Patients on Enzyme Replacement Therapy.

Gaucher disease (GD) is the most frequent sphingolipidosis, caused by biallelic pathogenic variants in the GBA1 gene encoding for ß-glucocerebrosidase (GCase, E.C. 3.2.1.45). The condition is characterized by hepatosplenomegaly, hematological abnormalities, and bone disease in both non-neuronopathic type 1 (GD1) and neuronopathic type 3 (GD3). Interestingly, GBA1 variants were found to be one of the most important risk factors for the development of Parkinson's disease (PD) in GD1 patients. We performed a comprehensive study regarding the two most disease-specific biomarkers, glucosylsphingosine (Lyso-Gb1) and α-synuclein for GD and PD, respectively. A total of 65 patients with GD treated with ERT (47 GD1 patients and 18 GD3 patients), 19 GBA1 pathogenic variant carriers (including 10 L444P carriers), and 16 healthy subjects were involved in the study. Lyso-Gb1 was assessed by dried blood spot testing. The level of α-synuclein as an mRNA transcript, total, and oligomer protein concentration were measured with real-time PCR and ELISA, respectively. α-synuclein mRNA level was found significantly elevated in GD3 patients and L444P carriers. GD1 patients, along with GBA1 carriers of an unknown or unconfirmed variant, as well as healthy controls, have the same low level of α-synuclein mRNA. There was no correlation found between the level of α-synuclein mRNA and age in GD patients treated with ERT, whereas there was a positive correlation in L444P carriers.

Gaucher: A Systematic Review on Oral and Radiological Aspects.

Background and Objectives: Gaucher disease (GD) is a lysosomal storage disorder with the genetic autosomal recessive transmission. Bone involvement is a prevalent finding in Gaucher disease. It causes deformity and limits daily activities and the quality of life. In 75% of patients, there is bone involvement. This review aims to evaluate the principal findings in the jaw by a Cone-beam computed tomography (CBTC) and X-ray orthopantomography; Materials and Methods: PubMed, Web of Science, Lilacs and Scopus were systematically searched until 31 December 2022. In addition, a manual search was performed using the bibliography of selected articles and a Google Scholar search. Clinical studies were selected that considered principal radiographic findings in radiography in a group of patients affected by GD. Results: Out of 5079 papers, four studies were included. The main findings are generalized rarefaction and enlarged narrow space, anodontia. Conclusions: The exact mechanism of bone manifestation is probably due to the infiltration of Gaucher cells in the bone marrow and, consequently, the destruction of bone architecture. All long bones are a potential means of skeletal manifestation. The jaw is more affected than the maxilla, and the principal features are cortical thinning, osteosclerosis, pseudocystic lesions, mental demineralization, flattening in the head of the condyle, effacement of anatomical structures, thickening of maxillary sinus mucosa. The dentist plays a crucial role in diagnosing and treating these patients. Sometimes the diagnosis can be made by a simple panoramic radiograph. All long bones are affected, and the mandible is particularly involved.

Hepatic, Splenic, and Bone Marrow Gaucheromas: A Case Series and Systematic Literature Review.

BACKGROUND AND AIMS: Gaucher disease (GD) is one of the most common lysosomal storage diseases. It is characterized by the accumulation of glucocerebroside lipids in the macrophages, with liver, spleen and bone marrow frequently affected. The affected organs can develop tumor-like lesions (Gaucheromas), which are difficult to diagnose. We present the Gaucheromas and their ultrasonographic characteristics. METHODS: We selected Gaucheromas and their ultrasonographic characteristics found in the last 5 years during the periodical evaluation of 74 adult GD patients in Romania. All the patients had magnetic resonance imaging examination for comparison. A systematic review of all the Gaucheroma-related articles was performed to compare our results with the literature. RESULTS: Gaucheromas were found in 7 adult patients: 4 in the spleen, 2 in the liver and one affecting the bone. No malignancy ultrasound characteristics were found and neither on MRI exams. In the literature, 10 articles reported Gaucheromas, most of them in the liver and spleen in type 1 GD patients. All our patients were also type 1 GD, and the ultrasound aspect did not change during the 5 years follow-up. CONCLUSIONS: Gaucheromas can be found in any patient with GD. Malignancies have to be considered unless proven otherwise. Imaging characterization (ultrasound and MRI) are useful as histopathologic examination is difficult to obtain in all cases.

Expanding the phenotypic landscape of Gaucher disease type 3c with a novel entity - Transient neonatal cholestasis.

Gaucher disease (GD) is the most frequent lysosomal storage disorder due to biallelic pathogenic variants in GBA gene. Only homozygous D409H variant has been associated with the cardiovascular phenotype which is also known as Gaucher disease type 3c. In this descriptive study, we presented phenotypic heterogeneity and a novel clinical finding among 13 patients with GD type 3c. Patients presented with varying degrees of cardiac valve and/or aortic calcifications (84,6%) and corneal opacities (76,9%) in addition to visceral (100%), hematological (92,3%), neurological (92,3%), and skeletal (30%) manifestations. Also, cervical dystonia (38,4%) and psychiatric disorders (46,1%) were not infrequent entities with respect to neurological involvement in GD type 3c. In this report, we highlight transient neonatal cholestasis (38,4%) as a novel finding in GD type 3c. Neonatal cholestasis is a finding associated with Gaucher type 2, but transient neonatal cholestasis has not been reported in GD patients, so far. The clinical features of GD type 3c are highly heterogeneous, from disease severity or age of onset to disease progression. Also, we concluded that phenotypic spectrum may be associated with age at onset of clinical symptoms. As, patients presenting in infancy or childhood had mainly visceral and hematological involvement and patients presenting in adolescence and adulthood had mainly cardiac, neurological involvement, and psychiatric behavioral disorders. Identifying the heterogeneous clinical course of these patients in this fatal disease, may lead a sufficient understanding of the pathophysiology which will enable targeted therapeutic interventions.

Direct activation of microglia by ß-glucosylceramide causes phagocytosis of neurons that exacerbates Gaucher disease.

Gaucher disease (GD) is the most common lysosomal storage disease caused by recessive mutations in the degrading enzyme of ß-glucosylceramide (ß-GlcCer). However, it remains unclear how ß-GlcCer causes severe neuronopathic symptoms, which are not fully treated by current therapies. We herein found that ß-GlcCer accumulating in GD activated microglia through macrophage-inducible C-type lectin (Mincle) to induce phagocytosis of living neurons, which exacerbated Gaucher symptoms. This process was augmented by tumor necrosis factor (TNF) secreted from activated microglia that sensitized neurons for phagocytosis. This characteristic pathology was also observed in human neuronopathic GD. Blockade of these pathways in mice with a combination of FDA-approved drugs, minocycline (microglia activation inhibitor) and etanercept (TNF blocker), effectively protected neurons and ameliorated neuronopathic symptoms. In this study, we propose that limiting unrestrained microglia activation using drug repurposing provides a quickly applicable therapeutic option for fatal neuronopathic GD.

Utility of morphologic assessment of bone marrow biopsy in diagnosis of lysosomal storage disorders.

Introduction: Lysosomal storage disorders (LSDs) are rare disorders and pose a diagnostic challenge for clinicians owing to their generalized symptomatology. In this study, we aim to classify LSDs into two broad categories, namely, Gaucher disease (GD) and Niemann-Pick/Niemann-Pick-like diseases (NP/NP-like diseases) based on the morphology of the storage cells in the bone marrow (BM) aspiration smears and trephine biopsy sections. Materials and Method: This retrospective study includes 32 BM specimens morphologically diagnosed as LSDs at our institute, in the last 10 years. Subsequently, they were subclassified into GD and NP/NP-like diseases. Further, we have compared and analyzed the clinical, hematological, and biochemical parameters for the two groups of LSDs. Results: Based on BM morphology, 59.4% (n = 19) cases were diagnosed as NP/NP-like diseases and 40.6% (n = 13) cases as GD. Abdominal distension and failure to thrive were the most common clinical manifestations in both groups of LSDs. Anemia and thrombocytopenia were frequently seen in either of the LSDs. On the assessment of metabolic profile, elevated total/direct bilirubin and liver enzymes were more commonly seen in NP/NP-like diseases when compared with GD. Conclusion: We have classified LSDs into GD and NP/NP-like diseases based on the morphology of the storage cells in the BM specimen. The hallmark findings on BM biopsy annexed with the comparative features of the two proposed categories can aid the clinician in clinching the diagnosis. Formulation of such a methodology will prove instrumental for patient care in an underresourced setting.

The ovine Type II Gaucher disease model recapitulates aspects of human brain disease.

Acute neuronopathic (type II) Gaucher disease (GD) is a devastating, untreatable neurological disorder resulting from mutations in the glucocerebrosidase gene (GBA1), with subsequent accumulation of glucosylceramide and glucosylsphingosine. Patients experience progressive decline in neurological function, with onset typically within the first three-to-six months of life and premature death before two years. Mice and drosophila with GD have been described, however little is known about the brain pathology observed in the naturally occurring ovine model of GD. We have characterised pathological changes in GD lamb brain and compared the histological findings to those in GD patient post-mortem tissue, to determine the validity of the sheep as a model of this disease. Five GD and five age-matched unaffected lamb brains were examined. We observed significant expansion of the endo/lysosomal system in GD lamb cingulate gyrus however TPP1 and cathepsin D levels were unchanged or reduced. H&E staining revealed neurons with shrunken, hypereosinophilic cytoplasm and hyperchromatic or pyknotic nuclei (red neurons) that were also shrunken and deeply Nissl stain positive. Amoeboid microglia were noted throughout GD brain. Spheroidal inclusions reactive for TOMM20, ubiquitin and most strikingly, p-Tau were observed in many brain regions in GD lamb brain, potentially indicating disturbed axonal trafficking. Our findings suggest that the ovine model of GD exhibits similar pathological changes to human, mouse, and drosophila type II GD brain, and represents a model suitable for evaluating therapeutic intervention, particularly in utero-targeted approaches.

Ichthyosis, petechiae, and arthrogryposis in a neonate.

Gaucher disease is a rare lysosomal storage disorder caused by a deficiency in glucocerebrosidase. This enzyme deficiency leads to the accumulation of toxic metabolites in various organs. Multiple subtypes of this disease have been described; however, the perinatal-lethal form is extremely rare and challenging to diagnose. We present a case of a newborn girl with ichthyosis, petechiae, and arthrogryposis, later found to be homozygous for a pathogenic variant of the glucocerebrosidase gene. This case highlights the potential role of dermatologists in the recognition of this rare disease.

Patient centered guidelines for the laboratory diagnosis of Gaucher disease type 1.

Gaucher disease (GD) is an autosomal recessive lysosomal storage disorder due to the deficient activity of the acid beta-glucosidase (GCase) enzyme, resulting in the progressive lysosomal accumulation of glucosylceramide (GlcCer) and its deacylated derivate, glucosylsphingosine (GlcSph). GCase is encoded by the GBA1 gene, located on chromosome 1q21 16 kb upstream from a highly homologous pseudogene. To date, more than 400 GBA1 pathogenic variants have been reported, many of them derived from recombination events between the gene and the pseudogene. In the last years, the increased access to new technologies has led to an exponential growth in the number of diagnostic laboratories offering GD testing. However, both biochemical and genetic diagnosis of GD are challenging and to date no specific evidence-based guidelines for the laboratory diagnosis of GD have been published. The objective of the guidelines presented here is to provide evidence-based recommendations for the technical implementation and interpretation of biochemical and genetic testing for the diagnosis of GD to ensure a timely and accurate diagnosis for patients with GD worldwide. The guidelines have been developed by members of the Diagnostic Working group of the International Working Group of Gaucher Disease (IWGGD), a non-profit network established to promote clinical and basic research into GD for the ultimate purpose of improving the lives of patients with this disease. One of the goals of the IWGGD is to support equitable access to diagnosis of GD and to standardize procedures to ensure an accurate diagnosis. Therefore, a guideline development group consisting of biochemists and geneticists working in the field of GD diagnosis was established and a list of topics to be discussed was selected. In these guidelines, twenty recommendations are provided based on information gathered through a systematic review of the literature and two different diagnostic algorithms are presented, considering the geographical differences in the access to diagnostic services. Besides, several gaps in the current diagnostic workflow were identified and actions to fulfill them were taken within the IWGGD. We believe that the implementation of recommendations provided in these guidelines will promote an equitable, timely and accurate diagnosis for patients with GD worldwide.

Cancer risk and gammopathies in 2123 adults with Gaucher disease type 1 in the International Gaucher Group Gaucher Registry.

There are numerous reports of cancers in Gaucher disease (GD) from mostly small single-center studies; however, precise risk estimates and cancer types involved have not been delineated. We conducted a study involving 2123 patients with GD type 1 (GD1) to assess the incidence of hematological malignancies, gammopathies, and solid tumors in an international observational study, the International Cooperative Gaucher Group Gaucher Registry (Clinicaltrials.gov: NCT00358943). Risk for cancer overall and for each type of malignancy was compared to the United States (US) population using the Surveillance, Epidemiology, and End Results database. Natural history of gammopathy was determined through assessing the progression from a diagnosis of monoclonal gammopathy of unknown significance (MGUS) to multiple myeloma (MM). Risk for hematological malignancies was more than four times higher than expected compared to the general population: non-Hodgkin lymphoma was approximately three times higher; MM was approximately nine times higher. Age-specific incidence rates of MGUS were unexpectedly high among younger patients. The 10-year cumulative incidence of MM after diagnosis of MGUS was 7.9%, comparable to the general population. Compared to the general US population, GD1 patients were at higher risk for solid malignancies of liver (2.9 times), kidney (2.8 times), melanoma (2.5 times), and breast (1.4 times). Colorectal, prostate, and lung cancer risks were lower than expected. These findings help advance care of patients with GD1 by supporting recommendations for individualized monitoring for malignancies and antecedents such as MGUS for MM and provoke important questions of the role of glucosylceramide and related sphingolipids in cancer biology.

Phagocytosis of Erythrocytes from Gaucher Patients Induces Phenotypic Modifications in Macrophages, Driving Them toward Gaucher Cells.

Gaucher disease (GD) is caused by glucocerebrosidase deficiency leading to the accumulation of sphingolipids in macrophages named "Gaucher's Cells". These cells are characterized by deregulated expression of cell surface markers, abnormal secretion of inflammatory cytokines, and iron sequestration. These cells are known to infiltrate tissues resulting in hematological manifestations, splenomegaly, and bone diseases. We have already demonstrated that Gaucher red blood cells exhibit altered properties suggesting their key role in GD clinical manifestations. We hypothesized that Gaucher's erythrocytes could be prone to premature destruction by macrophages contributing to the formation of altered macrophages and Gaucher-like cells. We conducted in vitro experiments of erythrophagocytosis using erythrocytes from Gaucher's patients or healthy donors. Our results showed an enhanced erythrophagocytosis of Gaucher red blood cells compared to healthy red blood cells, which is related to erythrocyte sphingolipids overload and reduced deformability. Importantly, we showed elevated expression of the antigen-presenting molecules CD1d and MHC-II and of the iron-regulator hepcidin in macrophages, as well as enhanced secretion of the pro-inflammatory cytokine IL-1ß after phagocytosis of GD erythrocytes. These results strongly suggested that erythrophagocytosis in GD contribute to phenotypic modifications in macrophages. This present study shows that erythrocytes-macrophages interactions may be crucial in GD pathophysiology and pathogenesis.