Gaucher disease: haematological presentations and complications

Non-neuronopathic Gaucher disease (Type I) in an elderly female: a case report

Introduction and importance

Gaucher disease is a rare autosomal recessive lysosomal storage disorder marked by a substantial reduction in beta-glucocerebrosidase activity. Historically, supportive treatments such as splenectomy and orthopedic interventions were employed, whereas recent advances have led to the approval of Enzyme Replacement Therapy (ERT) and Substrate Reduction Therapy (SRT) as therapeutic options.

Case presentation

The authors present the case of a 61-year-old female with chronic abdominal pain, abdominal fullness, pancytopenia, and hepatosplenomegaly, all indicative of Gaucher's disease, later confirmed by histopathological examination. The patient was informed about newer treatment options like ERT and SRT, as well as the traditional approach of splenectomy. However, due to financial constraints, she opted for splenectomy in conjunction with conservative management.

Discussion

Gaucher disease is defined by a deficiency of glucocerebrosidase, leading to the accumulation of Gaucher cells (pathognomonic of the disease), particularly in the spleen, liver, bone marrow, and lungs. Type 1 Gaucher disease (GD1) can manifest at any age, from childhood to late adulthood. Definitive diagnosis is confirmed by reduced beta-glucocerebrosidase activity. Traditionally, treatment options for GD1 have been supportive, including splenectomy, blood transfusions, and orthopedic procedures. However, SRT and ERT, though effective, remain prohibitively expensive and often inaccessible in low-resource settings.

Conclusion

Early diagnosis of Gaucher disease is challenging due to its rarity and should be considered in patients presenting with hepatosplenomegaly, pancytopenia, and low glucocerebrosidase activity.

Enzyme replacement therapy improves erythropoiesis and iron dysregulation in Gaucher disease

Anemia and hyperferritinemia are frequent findings at diagnosis of Gaucher disease (GD). Macrophage-independent dyserythropoiesis and abnormal iron metabolism have been shown. We evaluated hematological and iron status at diagnosis (T0) and the effect of enzyme replacement therapy (ERT) on erythropoiesis and iron utilization over 5-year follow-up in type 1 GD patients and in an ex vivo model of erythropoiesis from CD34 + peripheral blood cells. At T0, 41% of patients had anemia and 51% hyperferritinemia. Hemoglobin increased from 12.6 (T0) to 13.9 g/dL (T6), GFD15, a marker of ineffective erythropoiesis, decreased from 5401 to 710 pg/ml, and serum ferritin decreased from 614 to 140 mcg/L (p < 0.001). In parallel, transferrin saturation (TSAT) increased. Hepcidin, although in the normal range, decreased from T0 to T6. Ex vivo studies showed that ERT restores the erythroid cells derived from CD34 + impaired ability to differentiate. During ERT, an increase in TFRC expression, consistent with the ability of erythroid precursors to uptake iron, and a reduction in HAMP and concomitant increase in SLC40A1 were observed. This is the largest study with a longitudinal follow-up evaluating erythropoiesis and iron metabolism, combining clinical and ex vivo data in GD. Iron dysregulation likely contributes to anemia, and ERT, by improving iron distribution, improves erythropoiesis.

Primer Part 1 - Preparing a laboratory quality improvement project

Quality in laboratory medicine encompasses multiple components related to total quality management, including quality control (QC), quality assurance (QA), quality indicators, and quality improvement (QI). Together, they contribute to minimizing errors (pre-analytical, analytical, or post-analytical) in clinical service delivery and improving process appropriateness and efficiency. In contrast to static quality benchmarks (QC, QA, quality indicators), the QI paradigm is a continuous approach to systemic process improvement for optimizing patient safety, timeliness, effectiveness, and efficiency. Healthcare institutions have placed emphasis on applying the QI framework to identify and improve healthcare delivery. Despite QI's increasing importance, there is a lack of guidance on preparing, executing, and sustaining QI initiatives in the field of laboratory medicine. This has presented a significant barrier for clinical laboratorians to participate in and lead QI initiatives. This three-part primer series will bridge this knowledge gap by providing a guide for clinical laboratories to implement a QI project that issuccessful and sustainable. In the first article, we introduce the steps needed to prepare a QI project with focus on relevant methodology and tools related to problem identification, stakeholder engagement, root cause analysis (e.g., fishbone diagrams, Pareto charts and process mapping), and SMART aim establishment. Throughout, we describe a clinical vignette of a real QI project completed at our institution focused on serum protein electrophoresis (SPEP) utilization. This primer series is the first of its kind in laboratory medicine and will serve as a useful resource for future engagement of clinical laboratory leaders in QI initiatives.

Soluble mannose receptor: A potential biomarker in Gaucher disease

PURPOSE

Soluble mannose receptor (sMR) relates to mannose receptor expression on macrophages, and is elevated in inflammatory disorders. Gaucher disease (GD) has altered macrophage function and utilises mannose receptors for enzyme replacement therapy (ERT) endocytosis. sMR has not previously been studied in GD.

METHODS

sMR was measured by ELISA and correlated with GD clinical features including spleen and liver volume, haemoglobin and platelet count, bone marrow burden (BMB) scores and immunoglobulin levels. sMR was compared with biomarkers of GD: chitotriosidase, lyso-GL1, PARC, CCL3, CCL4, osteoactivin, serum ACE and ferritin.

RESULTS

Median sMR in untreated GD patients was 303.0 ng/mL compared to post-treatment 190.9 ng/mL (p = .02) and healthy controls 202 ng/mL. Median sMR correlated with median spleen volume 455 mL (r = .70, p = .04), liver volume 2025 mL (r = .64, p = .04), BMB 7 (r = .8, p = .03), IgA 1.9 g/L (r = .54, p = .036), IgG 9.2 g/L (r = .57, p = .027), IgM 1.45 g/L (r = .86, p < .0001), with inverse correlation to median platelet count of 125 × 109/L (r = -.47, p = .08) and haemoglobin of 137 g/L (r = -.77, p = .0008). sMR correlated with established biomarkers: osteoactivin 107.8 ng/mL (r = .58, p = .0006), chitotriosidase 3042 nmol/mL/h (r = .52, p = .0006), PARC 800 ng/mL (r = .67, p = .0068), ferritin 547 μg/L (r = .72, p = .002) and CCL3 50 pg/mL (r = .67, p = .007).

CONCLUSIONS

sMR correlates with clinical features and biomarkers of GD and reduces following therapy.

Glucose-6-phosphate dehydrogenase deficiency with coinherited Gaucher disease: A rare association

ABSTRACT

Anemia coexisting with Gaucher disease (GD) is often associated with non-hemolytic processes. Few cases of GD with autoimmune hemolytic anemia have been reported. However, literature on GD with concomitant nonimmune hemolytic anemia is scarce. A 1-year 6-month-old male child presented in 2018 with complaints of palpable mass in left upper abdomen, fever, cough, and vomiting. On examination, he had pallor, hepatosplenomegaly of 2 cm and 8 cm below costal margin, respectively. A clinical diagnosis of hemolytic anemia was suspected. Complete blood count revealed Hb---6.7 g/dL, TLC---8.9 × 10 3 /μL, platelet count---180 × 10 3 /μL. Peripheral smear showed predominantly microcytic hypochromic anemia with moderate degree of anisocytosis, many nucleated red blood cells, few schistocytes, polychromatophils and corrected reticulocyte count 7.89%. S. Bilirubin was 1.1 mg/dL. Hb high-performance liquid chromatography (HPLC) of the child and his parents was within normal limit. Hematological work up revealed negative results for direct Coombs' test, osmotic fragility test, and sickling test. Test for Glucose-6-phosphate dehydrogenase deficiency was positive (39 units/trillion RBC, normal 146--376). He was transfused intermittently and given steroids to manage his anemia. He was on regular follow up during which his blood counts revealed persistent anemia and thrombocytopenia. In view of this, bone marrow was performed to exclude myelofibrosis. Aspirate smears were cellular and showed normoblastic erythroid hyperplasia. Numerous large histiocytes with basophilic fibrillary cytoplasm exhibiting "crumpled tissue paper" appearance were seen. Similar findings were seen on bone marrow trephine biopsy. Genetic testing revealed pathogenic variations in the GBA gene. Beta glucosidase enzyme levels were low while chitotriosidase was raised (1109.19 nmol/hr/mL). A final diagnosis of G6PD with GD was made. The present study shows rare association of GD with Glucose-6-phosphate dehydrogenase deficiency.

Type 1 Gaucher's Disease. A Rare Genetic Lipid Metabolic Disorder Whose Diagnosis Was Concealed by Recurrent Malaria Infections in a 12-Year-Old Girl

Introduction

Gaucher disease is a rare autosomal recessive lysosomal storage disease with unknown prevalence in Africa and no record of the disease exists in Uganda.

Case Presentation

We report a case of a 12-year-old female, the last born of 6 from a family with no known familial disease who presented with non-neuronopathic Gaucher disease and superimposed malaria. The disease was initially misdiagnosed as hyperreactive malarial splenomegaly but was subsequently confirmed by examination of the bone marrow smear and core. The disease was managed supportively and splenectomy was done due to worsening hematological parameters. She currently takes morphine for bone pains in addition to physiotherapy.

Conclusion

Always HMS is a common complication in malaria endemic areas, other causes of hepatosplenomegaly need to be excluded before the diagnosis is made. Diagnosis and treatment of patients with rare conditions like GD is still a challenge in developing countries. Although splenectomy is indicated in GD, it should only be done when it is absolutely necessary.

Gaucher disease prevalence in 600 patients affected by monoclonal gammopathy of undetermined significance

BACKGROUND

Gaucher disease (GD) is a rare autosomal recessive inherited disorder caused by the lysosomal enzyme acid β-glucosidase deficiency. Many patients experience a critical delay in the diagnosis of up to 8-10 years due to its rarity and variability in signs and symptoms, with the consultation of several specialists.

PATIENTS AND METHODS

This prospective observational study analyzed the prevalence of GD in 600 patients with monoclonal gammopathy of uncertain significance (MGUS) from January 2018 until February 2022.

RESULTS

The mean age of participants was 66 years, with a mean monoclonal component of 0.58 g/dL. In 433 MGUS patients with available data, anemia (hemoglobin level < 10 g/dL) was present in 31 patients (7%), and thrombocytopenia (platelet count <100.000/mm3 ) in 24 (5.5%). Of 600 MGUS patients tested for acid β-glucosidase enzyme activity, 7 patients (1.2%) had activity below 2.5 nmol/h/mL. In comparison, GBA gene analysis was executed in 110 patients. It revealed 4 patients (0.7%) affected by GD (3 patients with compound heterozygous mutation and 1 with homozygous mutation), with a prevalence of 1 every 150 MGUS patients. Furthermore, 12 out of the remaining 106 evaluated patients (11%) were carriers of a single heterozygous mutation while having regular enzyme activity.

CONCLUSIONS

The clinical heterogeneity of GD and frequent lack of awareness among physicians often lead to diagnostic delays and severe clinical manifestations. The role of MGUS in the presence of at least one clinical sign, such as low platelet count, organomegaly, bone pain, or bleeding tendency, could aid in initiating GD screening with DBS, thus reducing the period between symptom onset and the diagnosis of this rare disease.

GAU-PED study for early diagnosis of Gaucher disease in children with splenomegaly and cytopenia

BACKGROUND

Gaucher disease (GD) diagnosis can be delayed due to non-specific symptoms and lack of awareness, leading to unnecessary procedures and irreversible complications. GAU-PED study aims to assess GD prevalence in a high-risk pediatric population and the presence, if any, of novel clinical or biochemical markers associated with GD.

MATERIALS AND METHODS

DBS samples were collected and tested for β-glucocerebrosidase enzyme activity for 154 patients selected through the algorithm proposed by Di Rocco et al. Patients showing β-glucocerebrosidase activity below normal values were recalled to confirm the enzyme deficiency with the gold standard essay on cellular homogenate. Patients tested positive at the gold standard analysis were evaluated through GBA1 gene sequencing.

RESULTS

14 out of 154 patients were diagnosed with GD, with a prevalence of 9.09% (5.06-14.78%, CI 95%). Hepatomegaly, thrombocytopenia, anemia, growth delay/deceleration, elevated serum ferritin, elevated Lyso-Gb1 and chitotriosidase were significantly associated with GD.

CONCLUSIONS

GD prevalence in a pediatric population at high-risk appeared to be higher compared to high-risk adults. Lyso-Gb1 was associated with GD diagnosis. The algorithm proposed by Di Rocco et al. can potentially improve the diagnostic accuracy of pediatric GD, allowing the prompt start of therapy, aiming to reduce irreversible complications.

Suicidal attempt with eliglustat overdose

Eliglustat is an orphan medicine used for long-term treatment of Gaucher disease type 1 (GD1) in adults. GD1 is a genetic condition, in which glucosylceramide builds up in the body, typically in liver, spleen, and bone. Clinical signs and symptoms of the disease are anemia, tiredness, easy bruising, hepatosplenomegaly, bone pain, and fractures. Eliglustat works by blocking glucosylceramide synthase (substrate reduction therapy). This medicine is subject to additional safety monitoring by regulatory authorities in the European Union. Scientific literature on eliglustat overdose is not available. We herein describe successful treatment of a suicidal attempt with massive eliglustat overdose. A 29-year-old female with GD1, a poor metabolizer of cytochrome P450 2D6 on a recommended daily dose of 84 mg of eliglustat, had taken 94 capsules of eliglustat (84 mg per capsule). One hour after ingestion of almost 8 g of eliglustat, the patient suffered from somnolence, severe bradycardia (37 bpm), and hypotension (systolic blood pressure of 70 mm Hg). After intravenous administration of atropine (1 mg) and cafedrine/theoadrenaline (100 mg/5 mg) by the called emergency physician, the patient resolved gradually. She remained 24 h with stable hemodynamics at a nearby intensive care unit. During continuous ECG monitoring, increased frequency of supraventricular ectopic activity and a first-degree atrioventricular block were observed. To our knowledge, this is the first case report on a suicidal attempt with eliglustat.

Long-term eliglustat treatment of Gaucher patients over up to 10 years in Vienna

Gaucher disease has been the first lysosomal storage disorder for which an enzyme replacement therapy has been approved in the 1990s and was the first to receive approval for a first-line substrate reduction therapy in 2015. Eliglustat treatment has been started in Austria in patients recruited to a clinical trial, followed by its long-term extension and prescription treatment overall covering up to 10 years. In this case series the experience of treating Gaucher patients with eliglustat in Vienna is summarized. Patients were either switched from enzyme replacement therapy or were therapy naïve. Significant improvements were shown in hematological (thrombocytes, hemoglobin) and visceral (spleen volume) manifestations as well as in biomarkers (chitotriosidase, glucosylsphingosine [lyso-GL1], angiotensin converting enzyme) in a routine setting in a therapy-naïve patient. Stability was found in switch patients with slight improvement in bone density. Eliglustat was generally very well tolerated. Patient selection and regular monitoring is required to ensure effective and safe use.

Genetic Analysis of Acid β-Glucosidase in Patients with Multiple Myeloma from Central Taiwan: A Small-Cohort Case-Control Study

Introduction

Multiple myeloma (MM) is an incurable, biologically heterogeneous disease of the plasma cells, associated with older age and is more common in men. Gaucher disease, caused by mutation in acid β-glucosidase (glucocerebrosidase, GBA) gene, has been linked to multiple cancers, especially MM. Pathological accumulation of glucosylceramide and complex glycosphingolipids coupled with chronic inflammation may be the cause of cancer in patients with Gaucher disease. In this study, we hypothesized patients with MM have mutations in the GBA gene and analyzed patients with MM to determine whether they have a higher frequency of GBA variants.

Methods

Twenty-four MM samples were acquired from the Human Biobank, China Medical University Hospital, Taichung, Taiwan. GBA mutations were detected by polymerase chain reaction-directed DNA sequencing.

Results

We found no mutations in the coding regions of GBA in any of the 24 study subjects. However, two single-nucleotide polymorphisms, rs2070679 and rs2361534, were identified. A significant difference was observed between the study and control groups (p = 0.0028) in rs2361534 allele distribution, with the C allele frequency being higher in patients (1/48, 2.1%) than in the control group (5/3030, 0.16%, Taiwan Biobank).

Conclusion

In this study, the sample size was limited and GBA enzyme activity was not measured; therefore, we could not establish a direct correlation between MM and GBA mutations. However, the association of rs2361534 suggests that regions around this single-nucleotide polymorphism may be involved in MM. The relationship between MM and GBA mutations remains unclear. A large sample is required for a detailed analysis of this potential relationship.

New correlations between ocular parameters and disease severity in Spanish patients with Gaucher's disease Type I

Background

Gaucher’s disease is associated with a high variety of structural and functional abnormalities in the eye, which do not always affect visual acuity. The purpose of this study was to analyse ocular features in Spanish patients with Gaucher’s disease type I, and to investigate their possible correlation with phenotypic and burden parameters of this entity.

Methods

This cross-sectional observational study compared parameters belonging to 18 eyes from 9 Spanish patients with Gaucher’s disease Type I with 80 eyes from 40 healthy controls. Complete ophthalmological examination included choroidal and retinal thickness maps with swept source optical coherence tomography. Systemic analysis included genotype, plasmatic biomarkers, [ferritin, chemokine ligand 18 (CCL18) and chitotriosidase (ChT)] and severity scoring systems results [“Gaucher Disease Severity Score Index Type I" (GauSSI-I) and “Gaucher disease severity scoring system” (GD-DS3)].

Results

Nine subjects (18 eyes) were cases (female: 55.5%, mean age 45 years; male: 44.5%, mean age 36 years) and 40 subjects (80 eyes) were controls (female: 49%, mean age 50 years; male: 51%, mean age 55 years). There were no statistically significant differences when comparing ocular parameters (visual acuity; axial length, refractive errors, corneal parameters, lens, retinal and choroidal thickness) between case and control subjects (p>0.05). A statistically significant moderate correlation was observed between lower retinal thickness and choroidal quadrants thickness and greater disease severity scores. A lower central retinal thickness also correlates with higher biological plasmatic levels, and has a statistically significant association with the most affected patient with genotype N370S/Del 55pb. Conversely, higher pachymetry involves a more severe plasmatic concentration of biomarkers.

Conclusions

Our results suggest that pachymetry, and retinal and choroidal thickness, are associated with burden biomarkers and disease severity index scores in Spanish patients with Gaucher’s disease Type I.

Unexpected Cause of Persistent Microcytosis and Neurological Symptoms in a Child: Niemann-Pick Disease Type C

Atypical microcytic anemias are rare diseases of iron/heme metabolism that can be diagnostically challenging. We report the case of a 2-year-old twin boy with neurodevelopmental delay and persistent microcytosis in whom atypical microcytic anemias was initially suspected. He had low blood iron and transferrin saturation with normal/high ferritin despite iron therapy. Hemoglobinopathies were excluded by conventional/DNA studies. Hepcidin was high but iron-refractory-iron-deficiency anemia was ruled out by a genetic panel. Bone marrow aspiration revealed foamy cells and iron depletion. A genetic study confirmed the diagnosis of Niemann-Pick disease type C which was finally considered the origin of microcytosis through anemia of chronic disease.

iPSC-Derived Gaucher Macrophages Display Growth Impairment and Activation of Inflammation-Related Cell Death

Gaucher disease is a lysosomal storage disorder characterized by β-glucosidase enzyme deficiency and substrate accumulation, especially in cells of the reticuloendothelial system. Typical features of the disease are the unrestrained activation of inflammatory mechanisms, whose molecular pathways are still unclear. To investigate biological mechanisms underlying the macrophage activation in GD, we derived iPSCs from a healthy donor and a GD patient line and differentiated them into hematopoietic progenitors. While GD iPSCs are able to efficiently give rise to CD33+/CD45+ myeloid progenitors, the maturation towards the CD14+/CD163+ monocyte/macrophages fate resulted enhanced in the GD lines, that in addition displayed a decreased growth potential compared to control cells either in semisolid or in liquid culture. The GD lines growth impairment was associated with a significant upregulation of RIPK3 and MLKL, two key effectors of necroptosis, the inflammation related cell death pathway. The activation of necroptosis, which has already been linked to neuronopathic GD, may play a role in the disease proinflammatory condition and in the identified cell growth defects. Understanding the GD macrophage role in the alteration of mechanisms linked to cellular metabolism imbalance, cell death and inflammation are crucial in identifying new ways to approach the disease.

Non-immune Hemolysis in Gaucher Disease and Review of the Literature

Gaucher disease (GD) is an autosomal recessive disease characterized by the buildup of glucocerebrosides in macrophages, resulting in the formation of "Gaucher cells." These cells predominantly infiltrate the liver, spleen, and bone marrow leading to hepatosplenomegaly, cytopenia, and bone pain. Anemia in GD is typically considered to result from non-hemolytic processes. Although rare, a higher rate of hemolytic anemia of the autoimmune type has been reported in GD than in the general population. The literature on non-immune hemolytic anemia in GD is scarce. We review the literature on hemolytic anemia in GD and report on a case of non-immune hemolytic anemia secondary to GD. We believe this is the first description of a patient with confirmed GD and symptomatic non-immune hemolytic anemia that responded to GD-specific treatment.

Correction of pathology in mice displaying Gaucher disease type 1 by a clinically-applicable lentiviral vector

Gaucher disease type 1 (GD1) is an inherited lysosomal disorder with multisystemic effects in patients. Hallmark symptoms include hepatosplenomegaly, cytopenias, and bone disease with varying degrees of severity. Mutations in a single gene, glucosidase beta acid 1 (GBA1), are the underlying cause for the disorder, resulting in insufficient activity of the enzyme glucocerebrosidase, which in turn leads to a progressive accumulation of the lipid component glucocerebroside. In this study, we treat mice with signs consistent with GD1, with hematopoietic stem/progenitor cells transduced with a lentiviral vector containing an RNA transcript that, after reverse transcription, results in codon-optimized cDNA that, upon its integration into the genome encodes for functional human glucocerebrosidase. Five months after gene transfer, a highly significant reduction in glucocerebroside accumulation with subsequent reversal of hepatosplenomegaly, restoration of blood parameters, and a tendency of increased bone mass and density was evident in vector-treated mice compared to non-treated controls. Furthermore, histopathology revealed a prominent reduction of Gaucher cell infiltration after gene therapy. The vector displayed an oligoclonal distribution pattern but with no sign of vector-induced clonal dominance and a typical lentiviral vector integration profile. Cumulatively, our findings support the initiation of the first clinical trial for GD1 using the lentiviral vector described here.

Successful treatment of Gaucher disease type 1 by enzyme replacement therapy over a 10-year duration in a Japanese pediatric patient: A case report

The prevalence of Gaucher disease (GD) in Japan is much lower than that in Western countries; therefore, data on Japanese pediatric patients with GD type 1 are currently limited. The present study reports on the case of a Japanese pediatric patient with GD type 1 who was diagnosed when she presented with hepatosplenomegaly, thrombocytopenia and slight anemia at the age of 2 years. Serology tests revealed high levels of acid phosphatase (ACP) and angiotensin-converting enzyme (ACE). A bone marrow biopsy revealed the presence of Gaucher cells. Abdominal MRI indicated huge hepatosplenomegaly. Erlenmeyer flask deformity was observed on X-ray examination. MRI of the femora featured a high-intensity area within the diaphysis region. The enzymatic activity of leukocyte β-glucosidase, the measurement of which is necessary for a definitive diagnosis of GD, had decreased to 186.7 nmol/h/mg (reference range, 1,424.0-2,338.0 nmol/h/mg). Based on these results, the patient was clinically diagnosed with GD. Glucocerebrosidase gene analysis identified the compound heterozygote mutation of F213I (c.754T>A) on exon 7 and L444P (c.1448T>C) on exon 11. Enzyme replacement therapy (ERT) along with an intravenous infusion of 60 U/kg of imiglucerase every other week was initiated following diagnosis. Hemoglobin levels and the platelet count gradually improved and normalized after two years. ACP and ACE levels, biomarkers of the progression of GD, also improved. Abdominal MRI at six months after the initiation of ERT revealed a decrease in the size of the liver and spleen, which normalized after 1 year. Conversely, MRI of the femora indicated no improvement in the high-intensity area within the diaphysis region for 10 years.

Outcomes of screening for gammopathies in children and adults with Gaucher disease type 1 in a cohort from Brazil and the United States

Multiple myeloma is the most common hematological malignancy in Gaucher disease type 1 (GD1). There is a lack of outcome data and consensus regarding screening of gammopathies. This study explores utility of screening in Porto Alegre, Brazil, and Cincinnati, Ohio. A retrospective analysis of clinical information and laboratory data from GD1 patients was performed. Over 19 years, 68 individuals with GD1 (31 males, 37 females) underwent screening, and 20 (29.4%) had abnormalities. Twelve (17.6%) had polyclonal gammopathy (mean age 24.2 years, p = .02), seven (10%) had monoclonal gammopathy of uncertain significance (MGUS; mean age 52.7 years, p = .009). One had multiple myeloma (age 61 years). Risk factors for MGUS included male gender (p = .05), p.N409S allele (p = .032). MGUS developed in six of 62 treated and two of four untreated individuals. Of those with MGUS receiving treatment, four were on enzyme replacement therapy (ERT) and one on substrate reduction therapy (SRT). Gammopathy normalized in 13 treated individuals (10 polyclonal, three MGUS) and remained abnormal in two treated individuals (two polyclonal, two MGUS). Gammopathy relapse was seen in one individual with MGUS and three with polyclonal gammopathy. This study describes screening for gammopathies and identifies risk factors in individuals with GD1.

FAM46C and FNDC3A Are Multiple Myeloma Tumor Suppressors That Act in Concert to Impair Clearing of Protein Aggregates and Autophagy

Multiple myeloma is a plasma cell neoplasm characterized by the production of unfolded immunoglobulins, which cause endoplasmic reticulum (ER) stress and sensitivity to proteasome inhibition. The genomic landscape of multiple myeloma is characterized by the loss of several genes rarely mutated in other cancers that may underline specific weaknesses of multiple myeloma cells. One of these is FAM46C that is lost in more than 10% of patients with multiple myeloma. We show here that FAM46C is part of a new complex containing the ER-associated protein FNDC3A, which regulates trafficking and secretion and, by impairing autophagy, exacerbates proteostatic stress. Reconstitution of FAM46C in multiple myeloma cells that had lost it induced apoptosis and ER stress. Apoptosis was preceded by an increase of intracellular aggregates, which was not linked to increased translation of IgG mRNA, but rather to impairment of autophagy. Biochemical analysis showed that FAM46C requires interaction with ER bound protein FNDC3A to reside in the cytoplasmic side of the ER. FNDC3A was lost in some multiple myeloma cell lines. Importantly, depletion of FNDC3A increased the fitness of FAM46C-expressing cells and expression of FNDC3A in cells that had lost it recapitulated the effects of FAM46C, inducing aggregates and apoptosis. FAM46C and FNDC3A formed a complex that modulates secretion routes, increasing lysosome exocytosis. The cellular landscape generated by FAM46C/FNDC3A expression predicted sensitivity to sphingosine kinase inhibition. These results suggest that multiple myeloma cells remodel their trafficking machinery to cope with ER stress. SIGNIFICANCE: This study identifies a new multiple myeloma-specific tumor suppressor complex that regulates autophagy and unconventional secretion, highlighting the sensitivity of multiple myeloma cells to the accumulation of protein aggregates.

Gaucher disease status and treatment assessment: pilot study using magnetic resonance spectroscopy bone marrow fat fractions in pediatric patients

OBJECTIVE

To assess magnetic resonance spectroscopy (MRS) bone marrow fat fractions' ability to discern between untreated Gaucher disease patients and healthy controls based on assessment of bone marrow infiltration and evaluate response to enzyme replacement therapy (ERT) on serial imaging.

METHODS

This retrospective case-controlled study compared conventional MRI and bone marrow MRS findings in six pediatric and young adult Gaucher disease patients with age- and sex-matched controls, examining femoral neck and lumbar spine bone marrow fat fractions and bone marrow burden (BMB) scores. Separate analysis of six patients with serial imaging on ERT was performed with analysis of fat fractions, BMB scores, organ volumes, and serum chitotriosidase.

RESULTS

Untreated patients had significantly lower femoral and lumbar spine fat fractions than controls (0.32 versus 0.67, p = 0.041 and 0.17 versus 0.34, p = 0.041, respectively). Total BMB scores were significantly higher in patients (8.0 versus 3.5, p = 0.015). In patients on ERT with average follow-up of 3.5 years, femoral neck fat fraction was the sole significant predictor of treatment duration (R square: 0.804, p < 0.001) when adjusted for age. Femoral neck fat fraction also correlated with lumbar spine fat fraction, liver volume and chitotriosidase (p < 0.05). MRS test-retest reliability was excellent (Pearson correlations: 0.96, 0.99; p-values <0.001). BMB inter-rater reliability was good overall with an intra-class correlation coefficient of 0.79 for total score, although lumbar spine score reliability was poor at 0.45.

CONCLUSION

MRS-derived bone marrow fat fractions appear capable of detecting Gaucher disease severity and monitoring treatment-related changes as a predictor of ERT duration in pediatric and young adult patients.

Gaucher disease type 1 first recognized in an elderly patient with thrombocytopenia and lung adenocarcinoma

Recognizing Gaucher disease in elderly patients can be challenging. We present a Gaucher disease type 1 case diagnosed in an elderly patient with thrombocytopenia and lung adenocarcinoma. The diagnosis of Gaucher disease was delayed due to lack of familiarity about Gaucher Disease type 1 which can manifest in adulthood.

Imaging of non-neuronopathic Gaucher disease: recent advances in quantitative imaging and comprehensive assessment of disease involvement

Gaucher disease is an inherited metabolic disorder resulting in deficiency of lysosomal enzyme β-glucocerebrosidase causing the accumulation of abnormal macrophages (“Gaucher cells”) within multiple organs, most conspicuously affecting the liver, spleen, and bone marrow. As the most common glycolipid metabolism disorder, it is important for radiologists encountering these patients to be familiar with advances in imaging of organ and bone marrow involvement and understand the role of imaging in clinical decision-making. The recent advent of commercially available, reliable, and reproducible quantitative MRI acquisitions to measure fat fractions prompts revisiting the role of quantitative assessment of bone marrow involvement. This manuscript reviews the diverse imaging manifestations of Gaucher disease and discusses more optimal quantitative approaches to ascertain solid organ and bone marrow involvement with an emphasis on future applications of other quantitative methods including elastography.

Scaffolds for Sustained Release of Ambroxol Hydrochloride, a Pharmacological Chaperone That Increases the Activity of Misfolded β-Glucocerebrosidase

Ambroxol is a pharmacological chaperone (PC) for Gaucher disease that increases lysosomal activity of misfolded β-glucocerebrosidase (GCase) while displaying a safe toxicological profile. In this work, different poly(ε-caprolactone) (PCL)-based systems are developed to regulate the sustained release of small polar drugs in physiological environments. For this purpose, ambroxol is selected as test case since the encapsulation and release of PCs using polymeric scaffolds have not been explored yet. More specifically, ambroxol is successfully loaded in electrospun PCL microfibers, which are subsequently coated with additional PCL layers using dip-coating or spin-coating. The time needed to achieve 80% release of loaded ambroxol increases from ≈15 min for uncoated fibrous scaffolds to 3 days and 1 week for dip-coated and spin-coated systems, respectively. Furthermore, it is proven that the released drug maintains its bioactivity, protecting GCase against induced thermal denaturation.

Gaucher disease iPSC-derived osteoblasts have developmental and lysosomal defects that impair bone matrix deposition

Gaucher disease (GD) is caused by bi-allelic mutations in GBA1, the gene that encodes acid β-glucocerebrosidase (GCase). Individuals affected by GD have hematologic, visceral and bone abnormalities, and in severe cases there is also neurodegeneration. To shed light on the mechanisms by which mutant GBA1 causes bone disease, we examined the ability of human induced pluripotent stem cells (iPSC) derived from patients with Types 1, 2 and 3 GD, to differentiate to osteoblasts and carry out bone deposition. Differentiation of GD iPSC to osteoblasts revealed that these cells had developmental defects and lysosomal abnormalities that interfered with bone matrix deposition. Compared with controls, GD iPSC-derived osteoblasts exhibited reduced expression of osteoblast differentiation markers, and bone matrix protein and mineral deposition were defective. Concomitantly, canonical Wnt/β catenin signaling in the mutant osteoblasts was downregulated, whereas pharmacological Wnt activation with the GSK3β inhibitor CHIR99021 rescued GD osteoblast differentiation and bone matrix deposition. Importantly, incubation with recombinant GCase (rGCase) rescued the differentiation and bone-forming ability of GD osteoblasts, demonstrating that the abnormal GD phenotype was caused by GCase deficiency. GD osteoblasts were also defective in their ability to carry out Ca2+-dependent exocytosis, a lysosomal function that is necessary for bone matrix deposition. We conclude that normal GCase enzymatic activity is required for the differentiation and bone-forming activity of osteoblasts. Furthermore, the rescue of bone matrix deposition by pharmacological activation of Wnt/β catenin in GD osteoblasts uncovers a new therapeutic target for the treatment of bone abnormalities in GD.

Neuronopathic Gaucher disease presenting with microcytic hypochromic anemia

Gaucher disease (GD) is caused by a hereditary deficiency of glucocerebrosidase, resulting in accumulation of glucosylceramide and potentially manifesting as hepatosplenomegaly. We report the case of a 15-month-old boy with chronic neuronopathic GD. The patient had prolonged anemia despite continued iron supplementation for 3 months. White blood count (WBC), hemoglobin (Hb), platelet count, and corrected reticulocyte count were 3,300 /µL, 8.7 g/dL, 90,000 /µL, and 0.55, respectively. The patient had microcytic hypochromic anemia with mildly elevated ferritin. Physical examination revealed hepatosplenomegaly. Bone-marrow aspiration showed sheets of Gaucher cells. Glucocerebrosidase activity in monocytes was significantly lower than normal. Genetic analysis revealed a homozygous L444P mutation of GBA, and he was diagnosed with type 1 GD. Enzyme replacement treatment (ERT) consisting of imiglucerase was initiated and was effective; WBC, Hb, and platelet count gradually normalized and the hepatosplenomegaly improved. However, when the patient entered elementary school, he showed mild impaired cognitive function, and supranuclear gaze palsy occurred the same year. He was ultimately diagnosed with type 3 GD and continued ERT. Pediatric hemato-oncologists should be aware of GD, especially when patients exhibit anemia refractory to iron therapy, radiologic bone deformity, neurologic signs or symptoms, and growth retardation.

Lysosomal storage diseases

Lysosomal storage diseases (LSDs) are a group of over 70 diseases that are characterized by lysosomal dysfunction, most of which are inherited as autosomal recessive traits. These disorders are individually rare but collectively affect 1 in 5,000 live births. LSDs typically present in infancy and childhood, although adult-onset forms also occur. Most LSDs have a progressive neurodegenerative clinical course, although symptoms in other organ systems are frequent. LSD-associated genes encode different lysosomal proteins, including lysosomal enzymes and lysosomal membrane proteins. The lysosome is the key cellular hub for macromolecule catabolism, recycling and signalling, and defects that impair any of these functions cause the accumulation of undigested or partially digested macromolecules in lysosomes (that is, 'storage') or impair the transport of molecules, which can result in cellular damage. Consequently, the cellular pathogenesis of these diseases is complex and is currently incompletely understood. Several LSDs can be treated with approved, disease-specific therapies that are mostly based on enzyme replacement. However, small-molecule therapies, including substrate reduction and chaperone therapies, have also been developed and are approved for some LSDs, whereas gene therapy and genome editing are at advanced preclinical stages and, for a few disorders, have already progressed to the clinic.

Lysosomal storage diseases

Lysosomal storage diseases (LSDs) are a group of over 70 diseases that are characterized by lysosomal dysfunction, most of which are inherited as autosomal recessive traits. These disorders are individually rare but collectively affect 1 in 5,000 live births. LSDs typically present in infancy and childhood, although adult-onset forms also occur. Most LSDs have a progressive neurodegenerative clinical course, although symptoms in other organ systems are frequent. LSD-associated genes encode different lysosomal proteins, including lysosomal enzymes and lysosomal membrane proteins. The lysosome is the key cellular hub for macromolecule catabolism, recycling and signalling, and defects that impair any of these functions cause the accumulation of undigested or partially digested macromolecules in lysosomes (that is, 'storage') or impair the transport of molecules, which can result in cellular damage. Consequently, the cellular pathogenesis of these diseases is complex and is currently incompletely understood. Several LSDs can be treated with approved, disease-specific therapies that are mostly based on enzyme replacement. However, small-molecule therapies, including substrate reduction and chaperone therapies, have also been developed and are approved for some LSDs, whereas gene therapy and genome editing are at advanced preclinical stages and, for a few disorders, have already progressed to the clinic.

Biochemical and molecular characterization of adult patients with type I Gaucher disease and carrier frequency analysis of Leu444Pro - a common Gaucher disease mutation in India

Background

Gaucher disease is a rare pan-ethnic disorder which occurs due to an increased accumulation of undegraded glycolipid glucocerebroside inside the cells’ lysosomes. A beta-Glucosidase (GBA) gene defect results in glucocerebrosidase enzyme deficiency. Though the disease is mainly diagnosed in childhood, the adult manifestation is often missed or identified late due to the failure to recognize the heterogeneous clinical presentation. The present study includes seven unrelated Indian adult patients (age range: 20–40 years) having splenomegaly, with or without hepatomegaly, cytopenia and bone abnormality.

Methods

The biochemical investigation implicated measuring plasma chitotriosidase enzyme activity followed by confirmatory test of β-Glucosidase enzyme activity from the leukocytes. The molecular characterization involved patients’ initial screening for the common Gaucher mutation (Leu444Pro). Later, all patients were subjected to whole GBA gene coding region study using bidirectional Sanger sequencing. The population screening for common Gaucher disease mutation (Leu444Pro) was executed in 1200 unrelated and healthy Indian subjects by Restriction Fragment Length Polymorphism-Polymerase Chain Reaction technique. The allele frequency was calculated using Hardy-Weinberg formula.

Results

The biochemical analysis revealed a significant reduction in the β-Glucosidase activity in all the patients. Also, an elevated level of plasma Chitotriosidase activity in five patients supported their diagnosis of Gaucher disease. Sanger sequencing established four patients with homozygous variation and three patients with compound heterozygous variation in GBA gene. This study uncovers two missense variants (Ala448Thr and Val17Gly) not previously reported in Gaucher disease patients. Also the known mutations like Leu444Pro, Arg329Cys, Asp315Asn, Ser125Arg, and Arg395Cys were identified in these patients. The homology modeling suggested the destabilization of the protein structure due to novel variants. The Leu444Pro mutation screening in the Indian population spotted two people as a carrier. This emerged the carrier frequency of 1:600 along with wild-type allele frequency 0.97113 and mutant allele frequency 0.02887.

Conclusions

The study reports novel and known variants identified in the GBA gene in seven adult patients. The given study is the first report on the carrier frequency of the Leu444Pro mutant allele in an Indian population which will help understanding the burden and susceptibility of Gaucher disease to affect next generation in India.

Electronic supplementary material

The online version of this article (10.1186/s12881-018-0687-5) contains supplementary material, which is available to authorized users.

A health state utility valuation study to assess the impact of treatment mode of administration in Gaucher disease

Background

This study aimed to obtain UK societal-based utility values for health states related to treatment mode of administration using Gaucher disease as the background condition.

Methods

A review of relevant literature and expert clinical input informed the development of five health states characterising the impact of Gaucher disease and its management on patients’ lives. A base-state characterising the “controlled disease” was developed as well as four subsequent health states which varied in description of the method (intravenous versus oral) and frequency of treatment administration. Health state utilities were obtained using the time trade-off (TTO) method via face-to-face interviews with 100 members from the UK general population. Before the valuation exercise, participants provided informed consent, completed a demographic form and the EQ-5D, and ranked the health states from best to worst on a 0–100 visual analogue scale (VAS).

Results

Mean age of the participants (n = 100) was 35 years and 66% were female. Participants reported high EQ-5D VAS (86.1) and index scores (0.95) indicating very good health status. The “controlled disease” state had the highest mean TTO-derived utility value (0.89). There was only a marginal reduction in utility for the generic state for “Oral treatment” (0.85), while the reduction was more pronounced for the generic state for “Intravenous treatment” (0.73).

Conclusions

The findings suggest that the avoidance of the need for intravenous treatment administration is associated with a notable positive increase in health-related quality of life. Patient benefit arising from less invasive treatment could be an important consideration when undertaking economic evaluation of future therapies for Gaucher disease.

Electronic supplementary material

The online version of this article (10.1186/s13023-018-0903-6) contains supplementary material, which is available to authorized users.

A novel mutation causing type 1 Gaucher disease found in a Japanese patient with gastric cancer: A case report

RATIONALE

Gaucher disease (GD) is an autosomal recessive disorder that leads to multiorgan complications caused by β-glucocerebrosidase deficiency due to mutations in the β-glucocerebrosidase-encoding gene (GBA). GD morbidity in Japan is quite rare and clinical phenotype and gene mutation patterns of patients with GD in Japan and Western countries differ considerably. Of Japanese patients with GD, 57% develop types 2 or 3 GD with neurologic manifestations and younger onset, whereas only 6% of patients with GD develop those manifestations in Western countries. Thus, it is relatively difficult to find and diagnose GD in Japan.

PATIENT CONCERNS

A 69-year-old Japanese female with mild anemia and thrombocytopenia but without neurologic symptoms was initially referred for gastric cancer. Preoperative F-deoxyglucose positron emission tomography/computed tomography (FDG PET/CT) showed accumulation in the bone marrow and paraabdominal lymph nodes. Following bone marrow aspiration found, abnormal foamy macrophages in the bone marrow and electron microscopy revealed that the macrophages were filled with tubular-form structures. Adding to these signs suggestive of a lysosomal disease, serum β-glucocerebrosidase activity test found decreased. Sequencing of the patient's GBA gene revealed a RecNciI recombinant mutation and the novel mutation K157R (c.587A>G).

DIAGNOSES

On the basis of these findings and clinical manifestations, the final diagnosis of type 1 GD was made.

INTERVENTIONS

Enzyme replacement therapy (ERT) with velaglucerase α was started after the diagnosis of type 1 GD.

OUTCOMES

The patient's β-glucocerebrosidase activity as well as hemoglobin and platelet levels were restored by ERT without any side effects. Bone marrow aspirations 10 months after the start of the treatment with velaglucerase α showed reduction of Gaucher cells in bone marrow to 2% from 4% of total cellularity.

LESSONS

This is the first report of F-FDG PET/CT application providing a clue for GD diagnosis. A novel mutation in GBA is described, which implies a potential pool of patients with GD with this mutation in Japan.

Tuning protein folding in lysosomal storage diseases: the chemistry behind pharmacological chaperones

Misfolding of proteins is the basis of several proteinopathies. Chemical and pharmacological chaperones are small molecules capable of inducing the correct conformation of proteins, thus being of interest for human therapeutics. The most recent developments in medicinal chemistry and in the drug development of pharmacological chaperones are discussed, with focus on lysosomal storage diseases.

Non-neoplastic histiocytic and dendritic cell disorders in lymph nodes

Benign and malignant proliferations of histiocytes and dendritic cells may be encountered in lymph nodes. Reactive histiocytic and dendritic cell infiltrates occur in response to diverse stimuli and in addition to causing lymphadenopathy, may be present unexpectedly in lymph nodes excised for other indications. This review summarizes the pathogenesis and histopathological features of the various non-neoplastic histiocytic and dendritic cell infiltrates that can occur in lymph nodes.

Altered Differentiation Potential of Gaucher's Disease iPSC Neuronal Progenitors due to Wnt/β-Catenin Downregulation

Gaucher’s disease (GD) is an autosomal recessive disorder caused by mutations in the GBA1 gene, which encodes acid β-glucocerebrosidase (GCase). Severe GBA1 mutations cause neuropathology that manifests soon after birth, suggesting that GCase deficiency interferes with neuronal development. We found that neuronopathic GD induced pluripotent stem cell (iPSC)-derived neuronal progenitor cells (NPCs) exhibit developmental defects due to downregulation of canonical Wnt/β-catenin signaling and that GD iPSCs’ ability to differentiate to dopaminergic (DA) neurons was strikingly reduced due to early loss of DA progenitors. Incubation of the mutant cells with the Wnt activator CHIR99021 (CHIR) or with recombinant GCase restored Wnt/β-catenin signaling and rescued DA differentiation. We also found that GD NPCs exhibit lysosomal dysfunction, which may be involved in Wnt downregulation by mutant GCase. We conclude that neuronopathic mutations in GCase lead to neurodevelopmental abnormalities due to a critical requirement of this enzyme for canonical Wnt/β-catenin signaling at early stages of neurogenesis.

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Neuronopathic GBA1 mutations attenuate canonical Wnt signaling in iPSC-derived NPCs

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GD NPC differentiation to DA neurons impaired due to early loss of DA progenitors

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GBA1-mediated lysosomal alterations may be involved in Wnt signal downregulation

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The Wnt pathway may be a potential new therapeutic target for neuronopathic GD

Exploring the patient journey to diagnosis of Gaucher disease from the perspective of 212 patients with Gaucher disease and 16 Gaucher expert physicians

Gaucher disease (GD) is a rare hereditary disorder caused by a deficiency of the lysosomal enzyme β-glucocerebrosidase. Diagnosis is challenging owing to a wide variability in clinical manifestations and severity of symptoms. Many patients may experience marked delays in obtaining a definitive diagnosis. The two surveys reported herein aimed to explore the patient journey to diagnosis of GD from the perspectives of Gaucher expert physicians and patients. Findings from the surveys revealed that many patients experienced diagnostic delays and misdiagnoses, with nearly 1 in 6 patients stating that they were not diagnosed with GD for 7years or more after first consulting a doctor. Physicians and patients both reported multiple referrals to different specialties before a diagnosis of GD was obtained, with primary care, haematology/haematology-oncology and paediatrics the main specialties to which patients first presented. Splenomegaly, thrombocytopenia, anaemia and bone pain were reported as the most common medical problems at first presentation in both surveys. These findings support a clear need for straightforward and easy-to-follow guidance designed to assist non-specialists to identify earlier patients who are at risk of GD.

Patients' Opinions on Genetic Counseling on the Increased Risk of Parkinson Disease among Gaucher Disease Carriers

Gaucher disease (GD) is an autosomal recessive disease caused by GBA mutations that is especially common in the Ashkenazi Jewish (AJ) population. The link between GBA mutations and Parkinson disease (PD), a later-onset neurodegenerative condition, is well established, and studies have shown that GBA carriers have an increased lifetime risk of developing PD. Carrier screening for GD is frequently offered to couples during or prior to pregnancy, especially to those of AJ descent. However, no studies have been performed to assess if prospective parents would want to learn about their risk of developing PD incidentally through carrier screening. It is also unknown if pre-test counseling on this topic would affect screening uptake. In order to answer these questions, a survey was administered to individuals who screened negative for GBA mutations. Of the 75 participants, 86.7% believed that patients should be informed about the increased risk of PD prior to having GD carrier screening, and 93.3% responded that this information would not have changed their decision to have carrier screening. These results indicate that healthcare providers should take into consideration patient preferences when determining how to counsel about GD carrier screening. Additionally, these results have implications for genetic counseling about other later-onset conditions that may be incidentally ascertained through carrier screening.

Treatment of profound thrombocytopenia in a patient with Gaucher disease type 1: Is there a role for substrate reduction therapy

The availability of three enzyme replacement therapy (ERT) drugs and two substrate reduction therapy (SRT) drugs to treat Gaucher disease provides an opportunity to tailor therapies to a patient's specific clinical concerns. However, there is a gap in the literature regarding individual drug effectiveness in treating particular symptoms and the potential benefits of combination treatment.

This report details treatment of a patient with Gaucher disease type 1 whose main clinical concern was profound thrombocytopenia (around 20 × 10⁹/L, normal range: 150–450 × 10⁹/L) with several episodes of bleeding with minimal trauma and bruises. The patient was treated with ERT at doses up to 60 units/kg weekly, with no improvement in platelet levels for 6 years. Subsequently, the patient transitioned to SRT and platelet levels increased almost two fold within the first month, and have remained stable at safe levels (30–60 × 10⁹/L) for almost 2.5 years at the time of publication.

This report demonstrates a possible therapeutic benefit of SRT in individual patients who do not meet therapeutic goals in terms of thrombocytopenia after a considerable period on first-line ERT treatment. Oral administration of SRT also improved this patient's quality of life allowing discontinuation of weekly ERT infusions, which better accommodated her demanding career and busy lifestyle.

Case report of unexpected gastrointestinal involvement in type 1 Gaucher disease: comparison of eliglustat tartrate treatment and enzyme replacement therapy

BACKGROUND

Gastrointestinal involvement in Gaucher disease is very rare, and appears to be unresponsive to enzyme replacement therapy (ERT).

CASE PRESENTATION

Here, we describe identical twin, splenectomized, non-neuronopathic Gaucher patients on long-term ERT for 9 years, who complained of epigastric discomfort due to Gaucher cell infiltration of the gastroduodenal mucosa. Rare compound heterozygous mutations (p.Arg48Trp and p.Arg257Gln) of the GBA gene were found in both. Improvement in the gastroduodenal infiltration and reduced chitotriosidase levels were observed in one who switched to eliglustat tartrate for 1 year, whereas the other one who maintained ERT showed no improvement of chitotriosidase level and persistent duodenal lesions.

CONCLUSION

This shows that eliglustat might be an effective treatment for Gaucher disease patients having lesions resistant to ERT.

Diagnosis features of pediatric Gaucher disease patients in the era of enzymatic therapy, a national-base study from the Spanish Registry of Gaucher Disease

BACKGROUND

The enzymatic replacement therapy (ERT) availability for Gaucher disease (GD) has changed the landscape of the disease, several countries have screening programs. These actions have promoted the early diagnosis and avoided many complications in pediatric patients. In Spain ERT has been available since 1993 and 386 patients have been included in the Spanish Registry of Gaucher Disease (SpRGD). The aim of this study is to analyze the impact of ERT on the characteristics at time of diagnosis and initial complications in pediatric Gaucher disease patients.

AIM

To analyze the impact of ERT on the characteristics at time of diagnosis and initial complications in pediatric Gaucher disease patients.

METHODS

A review of data in SpRGD from patients' diagnosed before 18 years old was performed. The cohort was split according the year of diagnosis (≤1994, cohort A; ≥1995, cohort B).

RESULTS

A total of 98 pediatric patients were included, GD1: 80, GD3: 18; mean age: 7.2 (0.17-16.5) years, 58 (59.2%) males and 40 (40.8%) females. Forty-five were diagnosed ≤ 1994 and 53 ≥ 1995. Genotype: N370S/N370S: 2 (2.0%), N370S/L444P: 27 (27.5%), N370S/other: 47 (48%), L444P/L444P: 7 (7.1%), L444P/D409H: 2 (2.0%), L444P/other: 3 (6.2%), other/other: 10 (10.2%). The mean age at diagnosis was earlier in patients diagnosed after 1995 (p < 0.001) and different between the subtypes, GD1: 8.2 (0.2-16.5) years and GD3: 2.8 (0.17-10.2) years (p < 0.001). There were more severe patients in the group diagnosed before 1994 (p = 0.045) carrying L444P (2), D409H (2), G377S (1), G195W (1) or the recombinant mutation. The patients' diagnosed ≤1994 showed worse cytopenias, higher chance of bone vascular complications at diagnosis and previous spleen removal. The patients started ERT at a median time after diagnosis of 5.2 years [cohort A] and 1.6 years [cohort B] (p < 0.001).

CONCLUSIONS

The early diagnosis of Gaucher disease in the era of ERT availability has permitted to reduce the incidence of severe and irreversible initial complication in pediatric patients, and this has permitted better development of these patients. This is the largest pediatric cohort from a national registry.

Diastereomer-specific quantification of bioactive hexosylceramides from bacteria and mammals

Mammals synthesize, cell-type specifically, the diastereomeric hexosylceramides, β-galactosylceramide (GalCer) and β-glucosylceramide (GlcCer), which are involved in several diseases, such as sphingolipidosis, diabetes, chronic kidney diseases, or cancer. In contrast, Bacteroides fragilis, a member of the human gut microbiome, and the marine sponge, Agelas mauritianus, produce α-GalCer, one of the most potent stimulators for invariant natural killer T cells. To dissect the contribution of these individual stereoisomers to pathologies, we established a novel hydrophilic interaction chromatography-based LC-MS² method and separated (R > 1.5) corresponding diastereomers from each other, independent of their lipid anchors. Testing various bacterial and mammalian samples, we could separate, identify (including the lipid anchor composition), and quantify endogenous β-GlcCer, β-GalCer, and α-GalCer isomers without additional derivatization steps. Thereby, we show a selective decrease of β-GlcCers versus β-GalCers in cell-specific models of GlcCer synthase-deficiency and an increase of specific β-GlcCers due to loss of β-glucoceramidase 2 activity. Vice versa, β-GalCer increased specifically when cerebroside sulfotransferase (Gal3st1) was deleted. We further confirm β-GalCer as substrate of globotriaosylceramide synthase for galabiaosylceramide synthesis and identify additional members of the human gut microbiome to contain immunogenic α-GalCers. Finally, this method is shown to separate corresponding hexosylsphingosine standards, promoting its applicability in further investigations.