Modelling Gaucher disease progression: long-term enzyme replacement therapy reduces the incidence of splenectomy and bone complications

A Real-World Investigation of MRI Changes in Bone in Patients with Type 1 Gaucher Disease Treated with Velaglucerase Alfa: The EIROS Study

Background/Objectives: Gaucher disease type 1 (GD1) is characterized by hepatosplenomegaly, thrombocytopenia, and disabling bone manifestations requiring regular MRI monitoring. The EIROS study assessed the real-world impact of velaglucerase alfa on GD1 bone disease, using MRI data collected in French clinical practice. Methods: MRIs collected retrospectively from treatment initiation and prospectively during follow-up (12-months) were analyzed centrally by a blinded expert radiologist to evaluate bone infiltration using the Bone Marrow Burden (BMB) score and a qualitative method (stable, improved or worsened for the spine and femur). Abdominal MRIs were also centrally analyzed to assess hepatosplenomegaly. Bone manifestations, hepatosplenomegaly, and hematologic parameters were analyzed from medical records. Results: MRI data were available for 20 patients: 6 treatment-naive patients and 14 patients who switched to velaglucerase alfa from another GD treatment. Interpretable MRIs for BMB scoring were available for seven patients for the spine and one patient for the femur. Qualitative assessments (n = 18) revealed stability in spine and femur infiltration in 100.0% and 84.6% of treatment-switched patients (n = 13), respectively, and improvements in 80.0% and 60.0% of treatment-naive patients (n = 5), respectively; no worsening of bone infiltration was observed. Liver, spleen, and hematologic parameters improved in treatment-naive patients and remained stable in treatment-switched patients. Conclusions: The qualitative real-world data support findings from clinical trials suggesting the long-term effectiveness of velaglucerase alfa on GD1 bone manifestations. When MRI assessment by radiologists with experience of GD is not possible, a simplified qualitative assessment may be sufficient in clinical practice for monitoring bone disease progression and treatment response.

Osteonecrosis in Gaucher disease in the era of multiple therapies: Biomarker set for risk stratification from a tertiary referral center

Background

A salutary effect of treatments for Gaucher disease (GD) has been a reduction in the incidence of avascular osteonecrosis (AVN). However, there are reports of AVN in patients receiving enzyme replacement therapy (ERT) , and it is not known whether it is related to individual treatments, GBA genotypes, phenotypes, biomarkers of residual disease activity, or anti-drug antibodies. Prompted by development of AVN in several patients receiving ERT, we aimed to delineate the determinants of AVN in patients receiving ERT or eliglustat substrate reduction therapy (SRT) during 20 years in a tertiary referral center.

Methods

Longitudinal follow-ups of 155 GD patients between 2001 and 2021 were analyzed for episodes of AVN on therapy, type of therapy, GBA1 genotype, spleen status, biomarkers, and other disease indicators. We applied mixed-effects logistic model to delineate the independent correlates of AVN while receiving treatment.

Results

The patients received cumulative 1382 years of treatment. There were 16 episodes of AVN in 14 patients, with two episodes, each occurring in two patients. Heteroallelic p.Asn409Ser GD1 patients were 10 times (95% CI, 1.5-67.2) more likely than p.Asn409Ser homozygous patients to develop osteonecrosis during treatment. History of AVN prior to treatment initiation was associated with 4.8-fold increased risk of AVN on treatment (95% CI, 1.5-15.2). The risk of AVN among patients receiving velaglucerase ERT was 4.68 times higher compared to patients receiving imiglucerase ERT (95% CI, 1.67-13). No patient receiving eliglustat SRT suffered AVN. There was a significant correlation between GlcSph levels and AVN. Together, these biomarkers reliably predicted risk of AVN during therapy (ROC AUC 0.894, p<0.001).

Conclusions

There is a low, but significant risk of AVN in GD in the era of ERT/SRT. We found that increased risk of AVN was related to GBA genotype, history of AVN prior to treatment initiation, residual serum GlcSph level, and the type of ERT. No patient receiving SRT developed AVN. These findings exemplify a new approach to biomarker applications in a rare inborn error of metabolism to evaluate clinical outcomes in comprehensively followed patients and will aid identification of GD patients at higher risk of AVN who will benefit from closer monitoring and treatment optimization.

Funding

LSD Training Fellowship from Sanofi to MB.

Quantitation of a plasma biomarker profile for the early detection of Gaucher disease type 1 patients

Aim: Gaucher disease (GD) is caused by a deficiency of the lysosomal enzyme acid β-glucocerebrosidase. Recent metabolomic studies highlighted several new metabolites increased in the plasma of GD patients. We aimed to develop and validate a UPLC-MS/MS method allowing a relative quantitation of lyso-Gb₁ and lyso-Gb₁ analogs -28, -12, -2, +14, +16 and +18 Da in addition to sphingosylphosphorylcholine, N-palmitoyl-O-phosphocholine to study potential correlations with clinical manifestations. Methodology & results: Following solid-phase extraction, plasma samples were evaporated and resuspended in 100 μl of resuspension solution. Three microliter is injected into the UPLC-MS/MS for analysis. Conclusion: All biomarkers studied were increased in GD patients. Significant correlations were observed between specific analogs and hematological, and visceral complications, as well as overall disease severity.

Screening, patient identification, evaluation, and treatment in patients with Gaucher disease: Results from a Delphi consensus

Several guidelines are available for identification and management of patients with Gaucher disease, but the most recent guideline was published in 2013. Since then, there have been significant advances in newborn screening, phenotypic characterization, identification of biomarkers and their integration into clinical practice, and the development and approval of new treatment options. Accordingly, the goal of this Delphi consensus exercise was to extend prior initiatives of this type by addressing issues related to newborn screening, diagnostic evaluations, and treatment (both disease directed and adjunctive). The iterative Delphi process involved creation of an initial slate of statements, review by a steering committee, and three rounds of consensus development by an independent panel. A preliminary set of statements was developed by the supporting agency based on literature searches covering the period from 1965 to 2020. The Delphi process reduced an initial set of 185 statements to 65 for which there was unanimous support from the panel. The statements supported may ultimately provide a framework for more detailed treatment guidelines. In addition, the statements for which unanimous support could not be achieved help to identify evidence gaps that are targets for future research.

Economic burden and health related quality of life of ultra-rare Gaucher disease in China

Background

The diagnosis and health care of patients with rare diseases present a tremendous challenge worldwide. This study described the health care service utilization through participants’ perspective and estimated the cost of illness (COI), and patients with Gaucher disease (GD)’s/caregivers’ health-related quality of life in China.

Method

An online retrospective survey of patients with GD and their caregivers was conducted during May–June 2018. Socio-demographic, health service utilization, disease-related expenses, social support, sleep quality (Pittsburgh Sleep Quality Index [PSQI]), and the Short Form Health Survey (SF-36) were investigated. Using self-reported information, we estimated the annual COI, including direct healthcare, direct non-healthcare, and indirect costs.

Results

Forty patients and their 49 caregivers were surveyed. The patients’ onset age of GD was 9.3 ± 10.9; their disease course was 3.5 ± 3.1 years. 21 (42.9%) patients had ≥ 2 caregivers, but 35 (71.4%) caregivers reported have no experience as a caregiver. 79.6% caregivers have stopped working, and 87.8% changed weekly working schedule. Before final diagnosis, patients visited 3.9 ± 3.1 (max = 20) hospitals and took 1.2 ± 1.7 (max = 6.6) years for confirmed diagnosis. On average, 5.0 ± 9.6 misdiagnoses occurred, and the per-patient diagnoses cost was USD ($) 7576. After GD confirmation, 8 (16.3%) patients received no treatment, 40 (81.6%) received pharmacotherapy, 10 (20.4%) received surgery, 38 (77.6%) received outpatient service (8.8 ± 9.1 times/annually), and 37 (77.5%) received inpatient service (4.0 ± 3.5 times/annually). Annual per-patient COI was USD ($) 49,925 (95% confidence interval: 29,178, 70,672). Average direct healthcare cost was $41,816, including pharmaceutical ($29,908), inpatient ($7,451), and outpatient ($1,838). Productivity loss per-caregiver was $1,980, and their Zarit Burden Inventory score was moderate-severe (48.6 ± 19.6). Both patients/caregivers reported lower social support (32.4 ± 7.4, 34.9 ± 7.6), two times higher PSQI (7.9 ± 2.9, 8.7 ± 3.6), and half lower SF-36 (41.3 ± 18.6, 46.5 ± 19.3) than those reported for healthy Chinese individuals.

Conclusions

The high misdiagnosis rate, together with delayed diagnosis, substantial costs, and deteriorated health-related quality of life of GD patients as well as their heavy care burden, calls for extreme attention from policymakers in China. Further efforts of government and society are urgently demanded, including pharmaceutical reimbursement, screening newborns, developing precise diagnostic tools, and training doctors.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-021-01963-6.

Cardiac Manifestations in a Group of Romanian Patients with Gaucher Disease Type 1 (a Monocentric Study)

Gaucher disease (GD), one of the most common lysosomal disorders, is characterised by clinical heterogeneity. Cardiac involvement is rare and refers to pulmonary hypertension (PH), valvular abnormalities and myocardial infiltrative damage. The aim of this study was to evaluate cardiac involvement in a group of Romanian GD patients. Phenotypic and genotypic characterisation was carried out in 69 patients with GD type 1. Annual echocardiography and electrocardiography were performed to assess pulmonary pressure, morphology and function of the valves and electrocardiographic changes. Nine patients (13%) exhibited baseline echocardiographic signs suggesting PH. Mitral regurgitation was present in 33 patients (48%) and aortic regurgitation in 11 patients (16%). One patient presented aortic stenosis. Significant valvular dysfunction was diagnosed in 10% of patients. PH was associated with greater age (p < 0.001), longer time since splenectomy (p = 0.045) and longer time between clinical onset and the start of enzyme replacing therapy (p < 0.001). Electrocardiographic changes were present in five patients (7%).

Sphingolipid lysosomal storage diseases: from bench to bedside

Johann Ludwig Wilhelm Thudicum described sphingolipids (SLs) in the late nineteenth century, but it was only in the past fifty years that SL research surged in importance and applicability. Currently, sphingolipids and their metabolism are hotly debated topics in various biochemical fields. Similar to other macromolecular reactions, SL metabolism has important implications in health and disease in most cells. A plethora of SL-related genetic ailments has been described. Defects in SL catabolism can cause the accumulation of SLs, leading to many types of lysosomal storage diseases (LSDs) collectively called sphingolipidoses. These diseases mainly impact the neuronal and immune systems, but other systems can be affected as well. This review aims to present a comprehensive, up-to-date picture of the rapidly growing field of sphingolipid LSDs, their etiology, pathology, and potential therapeutic strategies. We first describe LSDs biochemically and briefly discuss their catabolism, followed by general aspects of the major diseases such as Gaucher, Krabbe, Fabry, and Farber among others. We conclude with an overview of the available and potential future therapies for many of the diseases. We strive to present the most important and recent findings from basic research and clinical applications, and to provide a valuable source for understanding these disorders.

Epidemiology, Pathogenesis, and Clinical Approach in Group 5 Pulmonary Hypertension

Pulmonary hypertension (PH) is recognized to be associated with a number of comorbid conditions. Based on these associations, PH is classified into 5 groups, considering common pathophysiologic drivers of disease, histopathologic features, clinical manifestations and course, and response to PH therapy. However, in some of these associated conditions, these characteristics are less well-understood. These include, among others, conditions commonly encountered in clinical practice such as sarcoidosis, sickle cell disease, myeloproliferative disorders, and chronic kidney disease/end stage renal disease. PH in these contexts presents a significant challenge to clinicians with respect to disease management. The most recent updated clinical classification schemata from the 6th World Symposium on PH classifies such entities in Group 5, highlighting the often unclear and/or multifactorial nature of PH. An in-depth review of the state of the science of Group 5 PH with respect to epidemiology, pathogenesis, and management is provided. Where applicable, future directions with respect to research needed to enhance understanding of the clinical course of these entities is also discussed.

A Cross-Sectional Retrospective Study of Non-Splenectomized and Never-Treated Patients with Type 1 Gaucher Disease

Patients with type 1 Gaucher disease (GD1) present thrombocytopenia, anemia, organomegaly, and bone complications. Most experts consider that the less aggressive forms do not require specific treatment. However, little is known about the disease course of these forms. The objective of this cross-sectional retrospective study was to compare the clinical, radiological, and laboratory characteristics of patients with less severe GD1 at diagnosis and at the last evaluation to identify features that might lead to potential complications. Non-splenectomized and never-treated patients (19 women and 17 men) were identified in the French Gaucher Disease Registry (FGDR). Their median age was 36.6 years (2.4–75.1), and their median follow-up was 7.8 years (0.4–32.4). Moreover, 38.7% were heterozygous for the GBA1 N370S variant, and 22.6% for the GBA1 L444P variant. From diagnosis to the last evaluation, GD1 did not worsen in 75% of these patients. Some parameters improved (fatigue and hemoglobin concentration), whereas platelet count and chitotriosidase level remained stable. In one patient (2.7%), Lewy body dementia was diagnosed at 46 years of age. Bone lesion onset was late and usually a single event in most patients. This analysis highlights the genotypic heterogeneity of this subgroup, in which disease could remain stable and even improve spontaneously. It also draws attention to the possible risk of Lewy body disease and late onset of bone complications, even if isolated, to be confirmed in larger series and with longer follow-up.

Biochemical and imaging parameters in acid sphingomyelinase deficiency: Potential utility as biomarkers

Acid Sphingomyelinase Deficiency (ASMD), or Niemann-Pick type A/B disease, is a rare lipid storage disorder leading to accumulation of sphingomyelin and its precursors primarily in macrophages. The disease has a broad phenotypic spectrum ranging from a fatal infantile form with severe neurological involvement (the infantile neurovisceral type) to a primarily visceral form with different degrees of pulmonary, liver, spleen and skeletal involvement (the chronic visceral type). With the upcoming possibility of treatment with enzyme replacement therapy, the need for biomarkers that predict or reflect disease progression has increased. Biomarkers should be validated for their use as surrogate markers of clinically relevant endpoints. In this review, clinically important endpoints as well as biochemical and imaging markers of ASMD are discussed and potential new biomarkers are identified. We suggest as the most promising biomarkers that may function as surrogate endpoints in the future: diffusion capacity measured by spirometry, spleen volume, platelet count, low-density lipoprotein cholesterol, liver fibrosis measured with a fibroscan, lysosphingomyelin and walked distance in six minutes. Currently, no biomarkers have been validated. Several plasma markers of lipid-laden cells, fibrosis or inflammation are of high potential as biomarkers and deserve further study. Based upon current guidelines for biomarkers, recommendations for the validation process are provided.

Effect of Substrate Reduction Therapy in Comparison to Enzyme Replacement Therapy on Immune Aspects and Bone Involvement in Gaucher Disease

Gaucher disease (GD) is caused by mutations in the GBA gene, leading to deficient activity of the lysosomal enzyme glucocerebrosidase. Among all the symptoms across various organ systems, bone disease is a major concern as it causes high morbidity and reduces quality of life. Enzyme replacement therapy (ERT) is the most accepted treatment; however, there are still unmet needs. As an alternative, substrate reduction therapy (SRT) was developed using glucosylceramide synthase inhibitors. In the current study, the effects of ERT vs. SRT were compared, particularly the immunological and bone remodeling aspects. GD subjects were divided into three cohorts based on their treatment at initial visit: ERT, SRT, and untreated (UT). Immunophenotyping showed no significant immune cell alterations between the cohorts. Expression of RANK/RANKL/Osteoprotegerin pathway components on immune cells and the secreted markers of bone turnover were analyzed. In the ERT cohort, no significant changes were observed in RANK, RANKL or serum biomarkers. RANKL on T lymphocytes, Osteopontin and MIP-1β decreased with SRT treatment indicating probable reduction in osteoclast activity. Other secreted factors, Osteocalcin and RANKL/Osteoprotegerin did not change with the treatment status. Insights from the study highlight personalized differences between subjects and possible use of RANK pathway components as markers for bone disease progression.

Subsidizing PGD: The Moral Case for Funding Genetic Selection

Preimplantation genetic diagnosis (PGD) allows the detection of genetic abnormalities in embryos produced through in vitro fertilization (IVF). Current funding models in Australia provide governmental subsidies for couples undergoing IVF, but do not extend to PGD. There are strong reasons for publicly funding PGD that follow from the moral principles of autonomy, beneficence and justice for both parents and children. We examine the objections to our proposal, specifically concerns regarding designer babies and the harm of disabled individuals, and show why these are substantially outweighed by arguments for subsidizing PGD. We argue that an acceptance of PGD is aligned with present attitudes towards procreative decision making and IVF use, and that it should therefore receive government funding.

A Comprehensive Study of Bone Manifestations in Adult Gaucher Disease Type 1 Patients in Argentina

Gaucher disease (GD) is the most prevalent lysosomal storage disease, and bone involvement is the most disabling condition. The aim of the present study was to evaluate bone involvement in adult patients with GD, using an observational cross-sectional study. Patients were evaluated using X-rays, bone densitometry (BMD), trabecular bone score (TBS), magnetic resonance imaging (MRI), and biochemical bone markers. Thirty-two type 1GD patients were included (mean age: 40 ± 16 years). Patients had received velaglucerase for 2.7 ± 1.4 years; 19/32 had been treated previously with imiglucerase. Ninety-four percent of subjects met therapeutic goals for hematological parameters, and eight were splenectomized (SPX). Nineteen patients had irreversible bone lesions (IL), i.e., avascular necrosis, bone infarction, and/or vertebral fractures. MRI showed marrow infiltration in 71% of patients. Patients with IL had higher bone marrow burden than those without (p = 0.001). All SPX patients had IL, a higher prevalence of bone marrow edema (p = 0.02), and lower TBS (p = 0.03) than non-SPX patients. Only 18.7% of patients had abnormal BMD, with no correlation with fractures (FX). TBS values were < 1350 in 53% of patients and tended to be lower in those with FX (p = 0.06). Patients with P1NP in the lower quartile had lower TBS (p = 0.03) than those with P1NP in the higher quartiles. TBS correlated moderately but not significantly with P1NP (r = 0.32) and BMB (r = - 0.44). A high prevalence of IL was documented. Bone quality was more affected than BMD in fracture patients. Low bone formation, active bone marrow infiltration, and splenectomy might be implicated in IL.

Plasma chitotriosidase activity versus plasma glucosylsphingosine in wide spectrum of Gaucher disease phenotypes - A statistical insight

Deficiency of beta-glucocerebrosidase (GBA) leads to Gaucher disease (GD), an inherited disorder characterised by storage of glucosylceramide (GlcCer) in lysosomes of tissue macrophages. Macrophages activated by accumulated GlcCer secrete chitotriosidase. Plasma chitotriosidase activity is significantly elevated in patients with active GD and has been suggested to indicate total body Gaucher cell load. There are two biomarkers used to assess the severity of GD - chitotriosidase has been measured for over 20 years, and deacylated GlcCer, known as glucosylsphingosine (GlcSph) is thought to be even more adequate, as it is almost a direct storage substrate. In this paper we focused entirely on statistical analysis, performing a thorough search of possible relations, dependencies and differences in the levels of these two biomarkers in a cohort of 64 Polish GD patients. We found that the treatment of GD with enzyme replacement therapy (ERT) changes the distribution of the disease biomarkers; their levels follow a normal distribution only in untreated patients. The variable "disease biomarker level" was found dependent of the binary variable "treated with ERT or not". It was found independent of the following variables: "disease type", "splenectomized or not", and "heterozygous for 24-bp duplication for CHIT1 variant" or "CHIT1 wild type". An almost perfect linear correlation (coefficient of determination R² = 0.99) between the chitotriosidase activity and GlcSph level was revealed in splenectomized patients.

Improvement of life quality measured by Lansky Score after enzymatic replacement therapy in children with Gaucher disease type 1

BACKGROUND

Gaucher disease type 1 (GD1, OMIM# 230800), is a condition with high impact in patient's quality of life (QoL). We report the improvement in QoL of children with GD1 measured by Lansky play-performance scale (LS) after enzymatic replacement therapy (ERT) and to describe our experience in the treatment of children with GD1.

METHODS

Five children with diagnosis of GD1 received imiglucerase 60 mg/kg every two weeks. LS, hepatomegaly, splenomegaly, hemoglobin, platelets, and growth rate were measured every 6 months after beginning ERT for 30 months.

RESULTS

After ERT, LS increased significantly from 28 ± 16.48 points before ERT to 70 ± 10 (P = 0.0046) and 95 ± 10 (P = 0.0022) points after 6 and 30 months of ERT, respectively; hemoglobin and platelets changed significantly from 9.28 ± 0.61 to 12.40 ± 0.85 (P = 0.0198) and from 71.50 ± 14.89 to 205.00 ± 65.34 (P = 0.0428) after 30 months of ERT, respectively. All patients demonstrated decreased hepatic and splenic size with mean reductions of 66% and 80% at 30 months of treatment and the USG longitudinal axis was reduced in both liver and spleen after ERT.

CONCLUSION

The use of ERT with imiglucerase 60 mg/kg every two weeks has substantial benefits and significantly improves QoL, assessed with Lansky Score, of the five children with GD1 studied.

Medical Management of Pulmonary Hypertension with Unclear and/or Multifactorial Mechanisms (Group 5): Is There a Role for Pulmonary Arterial Hypertension Medications?

PURPOSE OF REVIEW

The purpose of this review was to outline the mechanisms and to review recent literature on pulmonary arterial hypertension (PAH) medications in group 5 pulmonary hypertension (PH).

RECENT FINDINGS

The first steps in management are to understand the mechanisms and hemodynamic profile and to exclude chronic thromboembolic disease. Recent studies in the past 5 years have found that PAH medications may improve hemodynamics in patients with pre-capillary pulmonary hypertension due to sarcoidosis, pulmonary Langerhans cell histiocytosis, lymphangioleiomyomatosis, and myeloproliferative disorders with dasatinib-induced PH. Improvements in exercise capacity are uncommon, and no survival benefit has been demonstrated. There is a risk of pulmonary edema in patients with pulmonary venous involvement or fibrosing mediastinitis when treated with PAH therapies. There is limited evidence supporting the use of PAH medications in group 5 patients, and they may be harmful in certain cases. In most patients with group 5 PH, treatment should be directed to the underlying disease with PAH therapies reserved for patients with severe pre-capillary PH.

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.

Enzyme replacement therapy reverses B lymphocyte and dendritic cell dysregulations in patients with Gaucher Disease

Gaucher disease (GD) is caused by mutations in the GBA gene encoding lysosomal enzyme, β-glucocerebrosidase (GCase). GCase deficiency results in accumulation of its substrates in cells of macrophage lineage, affecting multiple organ systems. Enzyme replacement therapy (ERT) with recombinant human GCase is the standard of care to treat GD. In GD, it is well established that there are immune alterations, clinically presenting as lymphadenopathy, gammopathies, and predisposition to hematological cancers. We examined the effect of ERT on immune dysregulations in treatment-naïve GD patients longitudinally after the initiation of ERT. Immunophenotyping was performed in peripheral blood samples obtained before and after ERT. T and B lymphocyte subsets, NK, NKT and dendritic cells were evaluated. In all treatment naïve patients at baseline, transitional B cells, characterized by CD21^low expression were markedly elevated. After establishment of stable-dose therapy, CD21^low cells were significantly reduced and subsequent increase in CD21^Hi B lymphocytes indicated improved B cell maturation. Class-switching and memory B cell defects which were noted prior to treatment were found to be normalized. An increase in dendritic cells also resulted after the treatment. Our data shows that GD affects across various immune cell types and ERT or its effects directly improve affected immunological parameters.

Management goals for type 1 Gaucher disease: An expert consensus document from the European working group on Gaucher disease

Gaucher Disease type 1 (GD1) is a lysosomal disorder that affects many systems. Therapy improves the principal manifestations of the condition and, as a consequence, many patients show a modified phenotype which reflects manifestations of their disease that are refractory to treatment. More generally, it is increasingly recognised that information as to how a patient feels and functions [obtained by patient- reported outcome measurements (PROMs)] is critical to any comprehensive evaluation of treatment. A new set of management goals for GD1 in which both trends are reflected is needed. To this end, a modified Delphi procedure among 25 experts was performed. Based on a literature review and with input from patients, 65 potential goals were formulated as statements. Consensus was considered to be reached when ≥75% of the participants agreed to include that specific statement in the management goals. There was agreement on 42 statements. In addition to the traditional goals concerning haematological, visceral and bone manifestations, improvement in quality of life, fatigue and social participation, as well as early detection of long-term complications or associated diseases were included. When applying this set of goals in medical practice, the clinical status of the individual patient should be taken into account.

A Novel Functional Missense Mutation p.T219A in Type 1 Gaucher's Disease

Background:

Gaucher's disease (GD) is an autosomal recessive disorder caused by a deficiency of acid β-glucosidase (glucocerebrosidase [GBA]) that results in the accumulation of glucocerebroside within macrophages. Many mutations have been reported to be associated with this disorder. This study aimed to discover more mutations and provide data for the genetic pattern of the gene, which will help the development of quick and accurate genetic diagnostic tools for this disease.

Methods:

Genomic DNA was obtained from peripheral blood leukocytes of the patient and Sanger sequencing is used to sequence GBA gene. Sequence alignments of mammalian β-GBA (GCase) and three-dimensional protein structure prediction of the mutation were made. A construct of this mutant and its compound heterozygous counterpart were used to measure GCase in vitro.

Results:

GCase is relatively conserved at p.T219A. This novel mutation differs from its wild-type in structure. Moreover, it also causes a reduction in GCase enzyme activity.

Conclusion:

This novel mutation (c.655A>G, p.T219A) is a pathogenic missense mutation, which contributes to GD.

Biochemical response to substrate reduction therapy versus enzyme replacement therapy in Gaucher disease type 1 patients

Background

We retrospectively compared biochemical responses in type 1 Gaucher disease patients to treatment with glycosphingolipid synthesis inhibitors miglustat and eliglustat and ERT.

Methods

Seventeen GD1 patients were included (n = 6 eliglustat, (two switched from ERT), n = 9 miglustat (seven switchers), n = 4 ERT (median dose 60U/kg/m). Plasma protein markers reflecting disease burden (chitotriosidase, CCL18) and lipids reflecting substrate accumulation (glucosylsphingosine, glucosylceramide) were determined. Also, liver and spleen volumes, hemoglobin, platelets, and fat fraction were measured.

Results

In patients naïve to treatment, chitotriosidase, CCL18 and glucosylsphingosine decreased comparably upon eliglustat and ERT treatment, while the response to miglustat was less. After 2 years, median decrease of chitotriosidase was 89 % (range 77–98), 88 % (78–92) and 37 % (29–46) for eliglustat, ERT and miglustat naïve patients respectively; decrease of CCL18 was 73 % (63–78), 54 % (43–86), and 10 % (3–18); decrease of glucosylsphingosine was 86 % (78–93), 78 % (65–91), 48 % (46–50). Plasma glucosylceramide in eliglustat treated patients (n = 4) reached values below the normal range (n = 20 healthy controls). Biochemical markers decreased or stabilized in switchers from ERT to eliglustat (n = 2), but less in miglustat switchers (n = 7). Clinical parameters responded comparably upon eliglustat and ERT treatment.

Conclusions

Our explorative study provides evidence that biochemical markers respond comparably in patients receiving eliglustat treatment and ERT, while the corresponding response to miglustat treatment is less.

Persistent immune alterations and comorbidities in splenectomized patients with Gaucher disease

Gaucher disease (GD) is an autosomal recessive disorder caused by mutations in the gene encoding acid-β-glucosidase, resulting in functional disruptions in degradation of glycosphingolipids and lysosomal accumulation of the substrates. The most frequent clinical presentations of GD are thrombocytopenia, splenomegaly and bone pain. Prior to advent of enzyme replacement therapy, splenectomy was performed for complications of hypersplenism such as severe thrombocytopenia and transfusion dependency. Though there is evidence about worsening bone disease after splenectomy, there is no systematic study to assess its effects on the immune system in GD patients. In order to investigate the long-term immunological effects of splenectomy, we used flow cytometry to compare the immunophenotypes of GD patients who had undergone splenectomy (SGD) to those with intact spleen. The results show that SGD patients have significantly fewer CD27(+)/IgM(+) B-cells but more CD4(+)/CD45RO(+) and CD8(+)/CD45RO(+) T-cells. The most surprising finding was an almost complete absence of circulating dendritic cells in SGD patients. In addition, splenectomized subjects had comorbidities, the most common being monoclonal gammopathy of undetermined significance (MGUS). Taken together, these results highlight the persistence of multiple immune alterations and comorbidities coexisting in higher frequency in the SGD group and they are not affected by GD specific therapy.

Evaluation of disease burden and response to treatment in adults with type 1 Gaucher disease using a validated disease severity scoring system (DS3)

BACKGROUND

GD1-DS3 is an integrated assessment of type 1 Gaucher disease (GD1) burden based on bone, hematologic and visceral domains. We investigated this disease severity scoring system (DS3) methodology for initial assessment, long-term follow-up and evaluation of treatment responses.

METHODS

We enrolled 133 treated adult GD1 patients. Baseline DS3 scores were calculated near the initial treatment date and patients stratified by severity as marked (DS3 6.00-19.00), moderate (DS3 3.00-5.99), mild (DS3 < 3.00). Follow-up scores were calculated annually. Minimal clinically important improvement (MCII), is defined as ΔDS3 of -3.1.

RESULTS

PATIENT CHARACTERISTICS

N370S was the most common allele (118 patients had at least one), 52 were N370S/N370S (48/52 were Ashkenazi Jews), N370S/L444P was the most common genotype among non-Jews. Median age of treatment: 45 years; median follow-up: 14 years. Baseline DS3 scores: Patients with marked disease (N = 58; median 7.84) were least likely to be N370S homozygous (19 %) and most likely to have had splenectomy (53 %), early age at diagnosis (median 18 years) and major pre-treatment bone pathology (76 %). Among patients with moderate disease (N = 53; median 4.33), 49 % were N370S/N370S, 15.1 % had splenectomy and 17 % had major bone disease. Median age at diagnosis: 32 years. No patient with mild disease (N = 22; median 2.4) had splenectomy or major skeletal disease. Median age at diagnosis: 40 years. 68 % were N370S homozygous. Response to treatment: Health-state transitions occurred primarily during the early treatment years. At Year 5, among 48 evaluable patients with marked baseline disease, eight were unchanged in severity status whereas 40 had MCII of varying degrees with 11 scored as mild. Among 42 evaluable moderate patients, none worsened, 16 remained moderate and 26 improved to mild. Among 16 evaluable mild patients, 14 remained so and 2 had DS3 scores in the low moderate range.

CONCLUSIONS

DS3 is effective for assessing disease burden in GD1 and for monitoring response. ERT was associated with MCII in DS3 scores in patients with high severity. Nevertheless, despite better DS3 scores with treatment, GD1 patients especially those with splenectomy and pre-treatment bone pathology, continued to have bone complications.

Gaucher disease: the role of the specialist on metabolic bone diseases

According to European legislation, a disease can be considered rare or "orphan" when it affects less than 1 subject of 2000 (1). Often these diseases affecting the pediatric age, are complex diseases and chronically debilitating and for this motive need the intervention of multidisciplinary skills specific. Among the rare disease as affecting the skeleton more than 400 are characterized by dysplastic changes of the skeleton (2). Alongside the disorders affecting the skeleton primitively, many systemic diseases can have a bone involvement. Among these, the Gaucher disease (GD), an heterogeneous lysosomal storage determined by hereditary enzyme deficiency of β-glucosidase. Patients with this disease have skeletal disorders of varying severity (Erlenmeyer flask deformity, lytic lesions and osteonecrosis, pathological fractures) that affects both the bone marrow, both mineralized bone with progressive damage of the tissue. The bone disease is the most debilitating of GD and can have a significant impact on the quality of life of patients. Thorough evaluations by monitoring biochemical markers of bone turnover and instrumental, with a quantitative and qualitative evaluation of the bone, are of fundamental importance to intervene early so they can prevent complications irreversible.