A multicentre observational study for early diagnosis of Gaucher disease in patients with Splenomegaly and/or Thrombocytopenia

Study of Adult and Pediatric Spanish Patients with Cryptogenic Splenomegaly and Splenectomy

INTRODUCTION

The differential diagnosis of splenomegaly is a complex process that encompasses a wide variety of diseases. Moreover, it is not always standardized and lacks a definitive consensus on which tests should be performed and in what order. Gaucher disease (GD) and acid sphingomyelinase deficiency (ASMD) are lysosomal diseases (LD) that present with splenomegaly, the diagnosis of which requires a high index of suspicion and specific biochemical and genetic techniques. The aim of the project for the education and diagnosis of Gaucher disease and acid sphingomyelinase deficiency (PREDIGA) was to conduct educational training alongside an observational, multicenter, ambispective, cross-sectional, single-cohort study among patients having an enlarged spleen or undergone splenectomy to further assess these subjects to exclude two lysosomal diseases, namely GD and ASMD.

METHODS

Using dried blood spot (DBS) testing, we identified patients with abnormally low values of the enzymes glucocerebrosidase and acid sphingomyelinase, who then underwent sequencing of the GBA1 and SPMD1 genes, respectively. The study involved 34 hospitals and 52 medical specialists.

RESULTS

We identified 220 patients (208 adults and 12 children under 18 years) with cryptogenic splenomegaly or who had undergone splenectomy (12 patients) without having reached a diagnosis. The median age was 11 years (interquartile range [IQR] 3-16) in the pediatric population and 51 years (IQR 38-65) in the adult population. Lower-than-normal enzyme values were detected in 19 DBSs, confirming eight positive cases, which corresponded to six patients with GD and two with ASMD. The rest of the DBSs with low enzyme activity were not genetically confirmed (58%). We determined that lysosomal diseases accounted for 3.6% of cryptogenic splenomegaly/splenectomy cases in our setting: 2.7% were GD and 0.9% ASMD, in a ratio of 1 ASMD patient to every 3 GD patients. Lyso-GL1 values in patients with GD were elevated in all but one individual, corresponding to a child diagnosed at 4 months old. The variants detected in the GBA1 gene were consistent with the most frequent variants found in Spain.

DISCUSSION/CONCLUSION

The development and implementation of this protocol for the education and diagnosis of cryptogenic splenomegaly/splenectomy, even in asymptomatic patients, constitutes a comprehensive, simple, rapid, and effective screening method for the diagnosis of GD and ASMD.

The Unmet Needs of Lysosomal Storage Disorders from Early Diagnosis to Caregiving Pathways: An Italian Perspective

Background/Objective: Lysosomal storage diseases (LSDs) are a group of rare, inborn, metabolic errors characterized by deficiencies in normal lysosomal function and by the intralysosomal accumulation of undegraded substrates, resulting in the damage of multiple organ systems. The spectrum of clinical manifestations is extremely heterogeneous. LSD diagnosis and management still present many issues. Methods: A group of Italian experts and patients' representatives met to discuss some critical aspects, and among the most impactful are early diagnosis, the transition of the patient from pediatric to adult age, territorial management, and the multidisciplinary approach. Results: Possible solutions to diagnostic delays may be a widespread newborn screening and screening programs on selected populations. The lack of a structured transition process could be helped by the drafting of shared diagnostic and therapeutic care pathways beyond the availability of databases accessible to the different levels that manage a patient. Territorial management could benefit from telemedicine, but a homogeneous diffusion of home therapy, not yet everywhere possible, is essential. A fundamental role is played by the patient associations, which should be increasingly involved in the political choices. It is also crucial to create structured multidisciplinary teams of experts for disease management and comorbidities. A transversal need appears to be greater training on LSDs. In Italy, the "Statement of Udine" was developed to guide further steps towards improvements in inherited metabolic medicine in adults, referencing the experience from the United Kingdom. Conclusions: Much can be done for the early diagnosis and management of LSDs with an effective treatment, but many aspects need improvement for the overall management of the patient. An investment in dedicated resources, formal recognition, and training is needed to address these unmet needs.

Neuronopathic Gaucher disease: Rare in the West, common in the East

Gaucher disease (GD) stands as one of the most prevalent lysosomal disorders, yet neuronopathic GD (nGD) is an uncommon subset characterized by a wide array of clinical manifestations that complicate diagnosis, particularly when neurological symptoms are understated. nGD may manifest as the acute neuronopathic type, or GD type 2 (GD2), either prenatally or within the first weeks to months of life, whereas GD type 3 (GD3) symptoms may emerge at any point during childhood or occasionally in adolescence. The clinical presentation encompasses severe systemic involvement to mild visceral disease, often coupled with a spectrum of progressive neurological signs and symptoms such as cognitive impairment, ataxia, seizures, myoclonus, varying degrees of brainstem dysfunction presenting with stridor, apneic episodes, and/or impaired swallowing. This manuscript aims to provide a comprehensive review of the incidence, distinctive presentations, and diverse clinical phenotypes of nGD across various countries and regions. It will explore the natural history of the neurodegenerative process in GD, shedding light on its various manifestations during infancy and childhood, and offer insights into the diagnostic journey, the challenges faced in the clinical management, and current and investigative therapeutic approaches for GD's neurological variants.

Gaucher Disease or Acid Sphingomyelinase Deficiency? The Importance of Differential Diagnosis

Background: Gaucher disease is a lysosomal storage disorder caused by functional glucocerebrosidase enzyme deficiency. Hepatosplenomegaly and hematological complications are found in both Gaucher disease and Acid Sphingomyelinase Deficiency, which is caused by acid sphingomyelinase dysfunction. The possible overlap in clinical presentation can cause diagnostic errors in differential diagnosis. For this reason, in patients with an initial clinical suspicion of Gaucher disease, we aimed to carry out a parallel screening of acid sphingomyelinase and glucocerebrosidase. Methods: Peripheral blood samples of 627 patients were collected, and enzymatic activity analysis was performed on both glucocerebrosidase and acid sphingomyelinase. The specific gene was studied in samples with null or reduced enzymatic activity. Specific molecular biomarkers helped to achieve the correct diagnosis. Results: In 98.7% of patients, normal values of glucocerebrosidase activity excluded Gaucher disease. In 8 of 627 patients (1.3%), the glucocerebrosidase enzymatic activity assay was below the normal range, so genetic GBA1 analysis confirmed the enzymatic defect. Three patients (0.5%) had normal glucocerebrosidase activity, so they were not affected by Gaucher disease, and showed decreased acid sphingomyelinase activity. SMPD1 gene mutations responsible for Acid Sphingomyelinase Deficiency were found. The levels of specific biomarkers found in these patients further strengthened the genetic data. Conclusions: Our results suggest that in the presence of typical signs and symptoms of Gaucher disease, Acid Sphingomyelinase Deficiency should be considered. For this reason, the presence of hepatosplenomegaly, thrombocytopenia, leukocytopenia, and anemia should alert clinicians to analyze both enzymes by a combined screening. Today, enzyme replacement therapy is available for the treatment of both pathologies; therefore, prompt diagnosis is essential for patients to start accurate treatment and to avoid diagnostic delay.

A new multiplex analysis of glucosylsphingosine and globotriaosylsphingosine in dried blood spots by tandem mass spectrometry

Background

Gaucher's and Fabry's disease are two of the most common treatable lysosomal storage diseases, and have a wide spectrum of clinical symptoms. Early detection is important, because timely initiation of treatments can improve the disease status and prevent complications. However disease manifestations develop in childhood, diagnosis is delayed until adulthood partly due to the limitations of the currently used diagnostic pathway. The aim of this research is to develop and validate a multiplex assay and defining reference ranges, which do not exist at this moment, to improve and facilitate the entire diagnostic work up and enable treatment in an earlier stage of disease.

Methods and findings

Biomarkers glucosylsphingosine (GlcSph) and globotriaosylsphingosine (Lyso-Gb3) were detected and quantified using LC-MS/MS on dried blood spots. We developed an improved and new extraction method that allowed to measure GlcSph and Lyso-Gb3 in a multiplex analytical platform. After validation of the method, samples of 1480 individuals with normal enzymatic activity were collected to determine age and gender-related reference ranges.Our combination method showed a good linearity, precision, accuracy and limit of quantification with lack of carry-over following the specific international CLSI guidelines. The suggested protocol is robust, efficient, sensitive, specific, comprehensive and relatively cheap in order to accelerate the diagnostic process for both lysosomal storage diseases. The samples, with normal enzymatic activity, defined statistical relevant and clinical correct reference ranges for each specific age group by gender.

Conclusion

We report a multiplex LC-MS/MS method and relevant reference ranges that are appropriate for the targeted screening, diagnosis and follow-up of Fabry and Gaucher 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.

[Misdiagnosis of Gaucher disease in real life: Retrospective study of the French Gaucher's disease registry]

INTRODUCTION

Gaucher disease is an autosomal recessive genetic disorder. It is caused by a deficiency of the lysosomal enzyme, glucocerebrosidase which leads to an accumulation of glucosylceramide in the macrophages. Splenomegaly, hepatomegaly, cytopenias (anemia, thrombocytopenia) and bone disorders are the main symptoms. The diagnosis is often delayed, leading to unnecessary investigations and treatments, and delaying the specific treatment. The primary objective of our study was to establish, in patients who had a diagnostic delay of more than one year, the reported misdiagnoses before the final diagnosis. The secondary objectives were to investigate the risk factors associated with error and delayed diagnosis.

METHODS

Retrospective study including patients with Gaucher disease from the French Gaucher Disease Registry. Collection of data by a single investigator from a standardized form.

RESULTS

Among 83 patients with a known diagnostic delay, 13 patients (15 %) had one or two misdiagnoses. These included osteo-articular diagnoses (osteomyelitis, osteoarthritis, arthritis, osteochondritis, rheumatic fever, n=8), haematological diagnoses (gestational thrombocytopenia, immunological thrombocytopenia, n=4), infectious diagnoses (visceral leishmaniasis, mononucleosis, n=2) and hemochromatosis. The osteo-articular and infectious diagnoses concerned the child and the adolescent while the haematological diagnoses and the hemochromatosis concerned the adult. No factors were found associated with misdiagnoses. Patients with a diagnostic delay greater than one year were less likely to have hepatosplenomegaly as the first symptom.

CONCLUSION

There is a risk of diagnostic error related to phenotypic heterogeneity and lack of specificity of Gaucher disease symptoms. This study helps to better identify the misdiagnoses associated with Gaucher disease.

Similarities and differences between Gaucher disease and acid sphingomyelinase deficiency: An algorithm to support the diagnosis

Lysosomal storage disorders are a group of inborn errors of metabolism due to defects in proteins crucial for lysosomal function. Gaucher disease is the most common autosomal recessive lysosomal storage disorder due to mutations in the GBA1 gene, resulting in the lysosomal deficiency of glucocerebrosidase activity. Gaucher disease is characterized by the toxic accumulation of glucosylceramide in the reticuloendothelial system. Acid sphingomyelinase deficiency (ASMD), previously known as Niemann Pick A/B disease, is also an autosomal recessive lysosomal storage disorder due to mutations in the SMPD1 gene, which result in acid sphingomyelinase deficiency and the accumulation of sphingomyelin in mononuclear phagocytic system and hepatocytes. The phenotypic expression of Gaucher disease type 1 (GD1), the most common type, and chronic visceral ASMD may overlap for several signs or symptoms. Splenomegaly is detectable in approximately 90% of the patients in both conditions; however, since GD1 is more frequent than ASMD, clinicians are more prone to suspect it, often neglecting the diagnosis of ASMD. Based on previous experience, a group of experts in the clinical and laboratory diagnosis, management, and treatment of lysosomal storage disorders developed an algorithm for both GD1 and ASMD to support physicians, including primary care providers, internists, and specialists (e.g., hepatologists, hematologists, and pulmonologists) to suspect and differentiate GD1 and ASMD and to provide the appropriate referral.

Early diagnosis of Gaucher disease in Korean patients with unexplained splenomegaly: a multicenter observational study

Background

Gaucher disease (GD) is an autosomal recessive disorder characterized by excessive accumulation of glucosylceramide in multiple organs. This study was performed to determine the detection rate of GD in a selected patient population with unexplained splenomegaly in Korea.

Methods

This was a multicenter, observational study conducted at 18 sites in Korea between December 2016 and February 2020. Adult patients with unexplained splenomegaly were enrolled and tested for β-glucosidase enzyme activity on dried blood spots (DBS) and in peripheral blood leukocytes. Mutation analysis was performed if the test was positive or indeterminate for the enzyme assay. The primary endpoint was the percentage of patients with GD in patients with unexplained splenomegaly.

Results

A total of 352 patients were enrolled in this study (male patients, 199; mean age, 48.42 yr). Amongst them, 14.77% of patients had concomitant hepatomegaly. The most common sign related to GD was splenomegaly (100%), followed by thrombocytopenia (44.32%) and, anemia (40.91%). The β-glucosidase activity assay on DBS and peripheral leukocytes showed abnormal results in sixteen and six patients, respectively. Eight patients were tested for the mutation, seven of whom were negative and one patient showed a positive mutation analysis result. One female patient who presented with splenomegaly and thrombocytopenia was diagnosed with type 1 GD. The detection rate of GD was 0.2841% (exact 95% CI, 0.0072‒1.5726).

Conclusion

The detection rate of GD in probable high-risk patients in Korea was lower than expected. However, the role of hemato-oncologists is still important in the diagnosis of GD.

A cross-sectional web-based survey among haematologists and gastroenterologists in Japan to identify the key factors for early diagnosis of Gaucher Disease

BACKGROUND

Gaucher Disease (GD) is a rare, inherited metabolic disorder resulting from glucocerebrosidase deficiency. Patients benefit from early treatment as complications can arise from delayed diagnosis.

AIMS

To measure GD awareness among Japanese haematologists and gastroenterologists, who are the specialists most likely to encounter patients with symptoms recognised in the Gaucher Earlier Diagnosis Consensus (GED-C), such as hepatosplenomegaly and thrombocytopenia. Additionally, we aimed to determine key signs from the GED-C associated with early diagnosis.

METHODS

A quantitative web survey assessed Japanese haematologists and gastroenterologists for their i) basic awareness of GD, ii) explicit awareness of GD signs, iii) explicit awareness of GD treatments, and iv) accuracy in suspecting GD in model patients.

RESULTS

Survey results from 160 haematologists and 166 gastroenterologists indicated that more than 50% of haematologists were aware of GD symptoms, diagnostic criteria and/or treatments, and 38% of them had experienced or suspected GD. The majority of gastroenterologists were unaware of GD or knew the disease only by name, with 20% experiencing or suspecting GD in practice. Almost 70% of haematologists knew of enzyme replacement therapy (ERT), while 47% of gastroenterologists were not aware of any treatments for GD. Of the GED-C items, an awareness of bone-associated signs was correlated with accurate GD diagnosis in model patients and this awareness was greater among haematologists than gastroenterologists.

CONCLUSIONS

Our study showed that haematologists had greater awareness of GD than gastroenterologists, and that bone pain may be a key sign of GD to enhance early diagnosis. This article is protected by copyright. All rights reserved.

The diagnosis and management of Gaucher disease in pediatric patients: Where do we go from here?

Gaucher disease (GD) is an autosomal recessive inherited lysosomal storage disease that often presents in early childhood and is associated with damage to multiple organ systems. Many challenges associated with GD diagnosis and management arise from the considerable heterogeneity of disease presentations and natural history. Phenotypic classification has traditionally been based on the absence (in type 1 GD) or presence (in types 2 and 3 GD) of neurological involvement of varying severity. However, patient management and prediction of prognosis may be best served by a dynamic, evolving definition of individual phenotype rather than by a rigid system of classification. Patients may experience considerable delays in diagnosis, which can potentially be reduced by effective screening programs; however, program implementation can involve ethical and practical challenges. Variation in the clinical course of GD and an uncertain prognosis also complicate decisions concerning treatment initiation, with differing stakeholder perspectives around efficacy and acceptable cost/benefit ratio. We review the challenges faced by physicians in the diagnosis and management of GD in pediatric patients. We also consider future directions and goals, including acceleration of accurate diagnosis, improvements in the understanding of disease heterogeneity (natural history, response to treatment, and prognosis), the need for new treatments to address unmet needs for all forms of GD, and refinement of the tools for monitoring disease progression and treatment efficacy, such as specific biomarkers.

Novel Management and Screening Approaches for Haematological Complications of Gaucher's Disease

Purpose

Gaucher disease (GD) is the most common lysosomal storage disorder. The principal manifestations for its diagnosis and further monitoring include haematological manifestations such as anaemia, thrombocytopaenia, spleen enlargement, and bleeding disorders, among others. This review aims to summarise and update the role of haematological complications in GD diagnosis and follow-up, describe their management strategies, and to use these indicators as part of the diagnostic approach.

Materials and Methods

A systematic review following the recommendations of PRISMA-P 2020 was carried out. Publications indexed in the databases PubMed, Embase, Science Open, Mendeley, and Web of Science were electronically searched by three independent reviewers, and publications up to June 2021 were accessed. A total of 246 publications were initially listed, of which 129 were included for further review and analysis. Case reports were considered if they were representative of a relevant hematologic complication.

Results

From the first review dated in 1974 to the latest publication in 2021, including different populations confirmed that the haematological manifestations such as thrombocytopaenia and splenomegaly at diagnosis of GD type 1 are the most frequent features of the disease. The incorporation of haematological parameters to diagnosis strategies increases their cost-effectiveness. Hematologic parameters are part of the scoring system for disease assessment and the evaluation of therapeutic outcomes, providing reliable and accessible data to improve the management of GD. However, cytopaenia, underlying coagulation disorders, and platelet dysfunction need to be addressed, especially during pregnancy or surgery. Long-term haematological complications include the risk of neoplasia and immune impairment, an area of unmet need that is currently under research.

Conclusion

Haematological features are key for GD suspicion, diagnosis, and management. Normalization of hematological parameters is achieved with the treatment; however, there are unmet needs such as the underlying inflammatory status and the long-term risk of hematologic neoplasia.

Ambroxol chaperone therapy for Gaucher disease type I-associated liver cirrhosis and portal hypertension: a case report

BACKGROUND

Gaucher disease (GD) is a rare autosomal recessive inherited disease caused by the deficiency of glucocerebrosidase and characterized by a broad spectrum of clinical manifestations, including hepatosplenomegaly, bone infiltration, and cytopenia. Moreover, it is even involved in the central nervous system. GD is classified into three phenotypes on the ground of neurologic involvement: type 1 (GD1), the commonly adult-onset, non-neuropathic variant; type 2 (GD2), the acute neuropathic form; and type 3 (GD3), the severe chronic neuro-visceral form. Recently, several studies have shown a promising outcome of ambroxol chaperone therapy for the treatment of GD, but its therapeutic role in GD1-associated liver cirrhosis and portal hypertension was not verified.

CASE PRESENTATION

A 36-year-old male patient was admitted for esophageal varices lasting for one year with a 34-year history of liver and spleen enlargement. The patient was diagnosed with GD1 with cirrhosis and portal hypertension based on the identification of Gaucher cells and advanced fibrosis in the liver biopsy tissue and two known pathogenic mutations on the glucocerebrosidase (GBA) gene. The patient received 660 mg/d of ambroxol for up to two years. At his six-month follow-up, the patient exhibited a remarkable increase in GBA activity (+35.5%) and decrease in liver stiffness (-19.5%) and portal vein diameter (-41.2%) as examined by ultrasound elastography and computer tomography, respectively. At two-year follow-up, the liver stiffness was further reduced (-55.5%) in comparison with untreated patients.

CONCLUSION

This case report suggests that long-term treatment with high dose ambroxol may play a role in the reduction of hepatic fibrosis in GD1.

A Japanese Patient with Gaucher Disease Treated with the Oral Drug Eliglustat as Substrate Reducing Therapy

Gaucher disease is a rare genetic disorder caused by the deficiency of acid β-glucosidase to effectively catalyze the degradation of glucosylceramide to glucose and ceramide. We report here the case of a 31-year-old male Japanese patient with Gaucher disease who switched from enzyme replacement therapy (ERT) to substrate reducing therapy (SRT). Liver dysfunction was identified at a routine medical checkup, and the patient was referred to our hospital with “idiopathic liver disease.” Clinical laboratory tests indicated thrombocytopenia and splenomegaly, which are characteristic symptoms of Gaucher disease. To definitively diagnose Gaucher disease, a bone marrow biopsy and acid β-glucosidase activity measurement were conducted; the results supported a diagnosis of Gaucher disease. This case emphasizes that it is possible for periodic medical checkups in adults to lead to the diagnosis of rare genetic disorders. The patient underwent ERT treatment with imiglucerase for 5 years; the platelet count rapidly increased and the spleen size rapidly decreased, indicating a good response to the drug. However, the patient increasingly felt the burden of visiting the hospital for 2 h of infusion ERT every 2 weeks. Consequently, it was jointly decided that he should switch from ERT to SRT with an oral drug. This switch was successful with no deterioration of laboratory data. This case report is the first to describe a Japanese Gaucher disease patient treated with eliglustat for >2 years. We showed that SRT is a well-tolerated and effective option for the treatment of Gaucher disease.

Confounding factors in the diagnosis and clinical course of rare congenital hemolytic anemias

Congenital hemolytic anemias (CHAs) comprise defects of the erythrocyte membrane proteins and of red blood cell enzymes metabolism, along with alterations of erythropoiesis. These rare and heterogeneous conditions may generate several difficulties from the diagnostic point of view. Membrane defects include hereditary spherocytosis and elliptocytosis, and the group of hereditary stomatocytosis; glucose-6-phosphate dehydrogenase and pyruvate kinase, are the most common enzyme deficiencies. Among ultra-rare forms, it is worth reminding other enzyme defects (glucosephosphate isomerase, phosphofructokinase, adenylate kinase, triosephosphate isomerase, phosphoglycerate kinase, hexokinase, and pyrimidine 5′-nucleotidase), and congenital dyserythropoietic anemias. Family history, clinical findings (anemia, hemolysis, splenomegaly, gallstones, and iron overload), red cells morphology, and biochemical tests are well recognized diagnostic tools. Molecular findings are increasingly used, particularly in recessive and de novo cases, and may be fundamental in unraveling the diagnosis. Notably, several confounders may further challenge the diagnostic workup, including concomitant blood loss, nutrients deficiency, alterations of hemolytic markers due to other causes (alloimmunization, infectious agents, rare metabolic disorders), coexistence of other hemolytic disorders (autoimmune hemolytic anemia, paroxysmal nocturnal hemoglobinuria, etc.). Additional factors to be considered are the possible association with bone marrow, renal or hepatic diseases, other causes of iron overload (hereditary hemochromatosis, hemoglobinopathies, metabolic diseases), and the presence of extra-hematological signs/symptoms. In this review we provide some instructive clinical vignettes that highlight the difficulties and confounders encountered in the diagnosis and clinical management of CHAs.

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.

Predicting the probability of Gaucher disease in subjects with splenomegaly and thrombocytopenia

Hematologists are frequently involved in the diagnostic pathway of Gaucher disease type 1 (GD1) patients since they present several hematological signs. However, GD1 is mainly underdiagnosed because of a lack of awareness. In this multicenter study, we combine the use of a diagnostic algorithm with a simple test (β-glucosidase activity on Dried Blood Spot) in order to facilitate the diagnosis in a population presenting to the hematologist with splenomegaly and/or thrombocytopenia associated with other hematological signs. In this high-risk population, the prevalence of GD1 is 3.3%. We propose an equation that predicts the probability of having GD1 according to three parameters that are routinely evaluated: platelet count, ferritin, and transferrin saturation.

Liver steatosis is highly prevalent and is associated with metabolic risk factors and liver fibrosis in adult patients with type 1 Gaucher disease

BACKGROUND AND AIMS

Gaucher disease (GD) is associated with peculiar metabolic abnormalities (ie hypermetabolic state, peripheral insulin resistance, dyslipidaemia), partially reverted by enzyme replacement therapy (ERT) at the expense of weight gain. Such metabolic alterations together with an unhealthy lifestyle acquired by an ageing GD population may favour the development of liver steatosis. We aimed at evaluating the prevalence of significant liver steatosis and at identifying the factors associated with liver steatosis in a cohort of patients with type 1 GD.

METHODS

Twenty adult type 1 GD patients from an Italian academic referral centre were prospectively submitted to vibration-controlled transient elastography (Fibroscan®) with controlled attenuation parameter (CAP); significant steatosis was defined as CAP values ≥250 dB/min.

RESULTS

Median CAP values were 234 [165-358] dB/min and 8 patients (40%) had significant steatosis. Significant steatosis was associated with indices of adiposity (weight, BMI and waist circumference), high blood pressure, insulin resistance and metabolic syndrome. GD-related variables and dose and duration of ERT were not associated with significant steatosis. In the subgroup of 16 patients on stable ERT for at least 24 months, CAP resulted significantly and positively associated with liver stiffness (rho 0.559, P = .024).

CONCLUSIONS

Significant steatosis is highly prevalent in adult type 1 GD patients and is strongly associated with a worse metabolic profile, featuring metabolic dysfunction-associated fatty liver disease (MAFLD). MAFLD may determine liver fibrosis progression in GD patients on stable ERT and may be a risk factor for long-term liver-related complications.

Detection of glucosylsphingosine in dried blood spots for diagnosis of Gaucher disease by LC-MS/MS

INTRODUCTION

Gaucher disease (GD) is caused by a deficiency of β-glucosidase (GCase), leading to accumulation of glucosylceramide (GlcC) and glucosylsphingosine (Lyso-Gb1). Lyso-Gb1 is a reliable biomarker for GD.

OBJECTIVES

This study aims to develop a simple, effective and accurate method for the screening and diagnosis of GD using dried blood spot (DBS) samples.

METHODS

Lyso-Gb1 in DBS was extracted by 50% acetonitrile aqueous solution containing isotope-labeled internal standard and analyzed using liquid chromatography tandem mass spectrometry (LC-MS/MS). A reference interval was established by analyzing samples from 277 healthy controls. Lyso-Gb1 was detected in the residual DBS samples from 142 high-risk patients with splenomegaly and/or thrombocytopenia. Based on GCase activity in DBS, samples were classified into four groups: confirmed GD patients (n = 52), GD carriers (n = 5), false positive (n = 36) and negative (n = 49).

RESULTS

The optimized Lyso-Gb1 assay showed intra- and inter-assay variations ranged between 2.0%-8.2% and 3.8%-10.2%, respectively. Accuracies ranged from 93.5% to 112.6%. The lowest limit of quantification was 1 ng/mL. The normal reference interval of Lyso-Gb1 in DBS ranged from 2.1 to 9.9 ng/mL. Among the 142 subjects, except for one GD patient (Lyso-Gb1 > 2500 ng/mL), the Lyso-Gb1 concentrations in 51 GD patients ranged from 190.5 to 2380.6 ng/mL (the median 614.8 ng/mL). Also, one negative patient was found to have an elevated Lyso-Gb1 level (684.5 ng/mL), while the other patients were normal. The negative case was then confirmed to be an atypical GD patient with a c.1091A > G (p.Y364C) homozygous variant in PSAP gene by next generation sequencing.

CONCLUSIONS

The optimized method to determine Lyso-Gb1 in DBS was demonstrated as a useful tool for the screening and diagnosis of GD.

Liver involvement in Gaucher disease: A practical review for the hepatologist and the gastroenterologist

Gaucher disease (GD), a rare lysosomal storage disorder caused by deficient glucocerebrosidase activity and consequent accumulation of glycosphingolipids in the mononuclear phagocyte system, may progress to disabling and potentially life-threatening complications when left undiagnosed and untreated. Unfortunately, because of non-specific signs and symptoms and lack of awareness, patients with type 1 GD, the most common non-neuropathic variant, frequently experience diagnostic delays. Since splenomegaly and thrombocytopenia are the dominant clinical features in many GD patients leading to first medical contact, the hepatologist and the gastroenterologist need to be aware of this condition. Liver involvement has been reported in the majority of GD patients, and comprises hepatomegaly, with or without liver enzymes alteration, fibrosis/cirrhosis, portal hypertension, focal liver lesions, and cholelithiasis. Moreover, GD is associated with several biochemical alterations of potential interest for the hepatologist and the gastroenterologist, including hypergammaglobulinemia, hyperferritinemia and metabolic abnormalities, that may lead to misdiagnoses with chronic liver diseases of common etiology, such as primary hemochromatosis, autoimmune liver diseases or nonalcoholic fatty liver disease. This comprehensive review, based on the collaborative experience of physicians managing patients with GD, provides practical information on the clinical, histological and radiological hepatic manifestations of GD aiming at facilitating the diagnosis of GD for the hepatologist and the gastroenterologist.

High risk screening for Gaucher disease in patients with splenomegaly and/or thrombocytopenia in China: 55 cases identified

Gaucher disease (GD) is a common lysosomal storage disorder caused by deficiency of glucocerebrosidase (GCase) due to the pathogenic variants in the GBA gene. The aim of this study was to evaluate the performance of high risk screening program for GD by measuring the enzyme activities of GCase and chitotriosidease in dried blood spots of patients with splenomegaly and/or thrombocytopenia. A total of 787 subjects (364 females and 423 males) with unexplained splenomegaly and/or thrombocytopenia were enrolled in this study from May 2016 to Aug 2019. The cutoff value of GCase activity was set as less than 3.0 pmol/punch/h for screening positive. The diagnosis of GD was confirmed by Sanger sequencing of the GBA gene. Among 131 screening positive cases, 49 patients were confirmed GD. The positive predictive value was 37.4%.Three patients with boundary values (GCase 3-4 pmol/punch/h) and other three splenectomic patients with normal GCase activity were confirmed GD by GBA genetic analysis because of increased chitotriosidase or Gaucher cells in bone marrow. A total of 55 GD cases were identified. The sensitivity and specificity of the high risk screening were 98.2% and 89.5%, respectively. These 55 GD patients presented splenomegaly (100%), hepatomegaly (70.9%), thrombocytopenia (83.6%). The level of GCase in GD patients was (1.7 ± 1.6) pmol/punch/h. The increased chitotriosidase (383.8 ± 130.2 pmol/punch/h) was found in 42 (76.4%) patients with GD. Molecular genetic analysis identified 44 variants in the GBA gene, including 11 novel variants. The results showed the high risk screening for GD is accurate, rapid and cost-effective.

Early detection of lysosomal diseases by screening of cases of idiopathic splenomegaly and/or thrombocytopenia with a next-generation sequencing gene panel

Lysosomal diseases (LD) are a group of about 70 rare hereditary disorders (combined incidence 1:5000) in which diverse lysosomal functions are impaired, impacting multiple organs and systems. The first clinical signs and symptoms are usually unspecific and shared by hundreds of other disorders. Diagnosis of LD traditionally relies on performing specific enzymatic assays, if available, upon clinical suspicion of the disorder. However, the combination of the insidious onset of LD and the lack of awareness on these rare diseases among medical personnel results in undesirable diagnostic delays, with unchecked disease progression, appearance of complications and a worsened prognosis. We tested the usefulness of a next‐generation sequencing‐based gene panel for quick, early detection of LD among cases of idiopathic splenomegaly and/or thrombocytopenia, two of the earliest clinical signs observed in most LD. Our 73‐gene panel interrogated 28 genes for LD, 1 biomarker and 44 genes underlying non‐LD differential diagnoses. Among 38 unrelated patients, we elucidated eight cases (21%), five with LD (GM1 gangliosidosis, Sanfilippo disease A and B, Niemann‐Pick disease B, Gaucher disease) and three with non‐LD conditions. Interestingly, we identified three LD patients harboring pathogenic mutations in two LD genes each, which may result in unusual disease presentations and impact treatment. Turnaround time for panel screening and genetic validation was 1 month. Our results underline the usefulness of resequencing gene panels for quick and cost‐effective screening of LDs and disorders sharing with them early clinical signs.

Prevalence and predictors of liver fibrosis evaluated by vibration controlled transient elastography in type 1 Gaucher disease

BACKGROUND & AIMS

Long-term liver-related complications of Gaucher disease (GD) include cirrhosis, portal hypertension and hepatocellular carcinoma. Although liver fibrosis is the main determinant of adverse liver-related clinical outcomes, it has rarely been evaluated in previously published cohorts of GD patients. We aimed at: assessing the prevalence of significant liver fibrosis in a cohort of patients with type 1 GD; identifying its predictors among GD-related variables, enzyme replacement therapy (ERT) and metabolic features.

METHODS

37 adult type 1 GD patients from two Italian academic referral centers were prospectively submitted to vibration controlled transient elastography (Fibroscan®); significant fibrosis was defined as liver stiffness ≥7 kPa.

RESULTS

Median liver stiffness was 4.6 [3-15.1] kPa and 7 patients (19%) had significant fibrosis. Significant fibrosis was associated with splenectomy (p = .046) and with scores (DS3: p = .002; SSI: p = .026) and biomarkers (ACE: p = .016; HDL cholesterol: p = .004) of GD severity. Length of ERT was significantly lower in GD patients with significant fibrosis. In the subgroup of 29 patients who were on stable ERT for at least 24 months, further to splenectomy, GD severity and non-N370S GBA1 genotypes, also diastolic blood pressure, BMI and the number of metabolic syndrome (MetS) components emerged as factors significantly associated with significant fibrosis.

CONCLUSIONS

Significant fibrosis is present in a remarkable proportion of adult type 1 GD patients. Splenectomy, GD severity and GBA1 genotypes are major GD-related predictors of liver fibrosis. Length of ERT is inversely correlated with liver disease in GD patients, suggesting a beneficial effect of ERT on liver fibrosis. However, GD patients on stable ERT should be monitored for metabolic complications, since MetS features may enhance liver disease progression despite optimal GD control.

A pilot screening of high-risk Gaucher disease children using dried blood spot methods in Shandong province of China

Background

The study aim was to verify the feasibility of a diagnostic algorithm with the evaluation of beta glucocerebrosidase (GBA) activity on dried blood spots (DBS) in screening high-risk Gaucher disease (GD) children in China, and to investigate the GD prevalence in this selected population.

Methods

Children were recruited from 20 departments of pediatrics or children’s hospitals in Shandong Province, China, due to splenomegaly and/or thrombocytopenia associated with one or more of the following creteria: anemia, history of bone pain, monoclonal gammopathy of unknown significance (MGUS), polyclonal gammopathy and splenectomy. GBA activity on DBS was tested, and patients with DBS GBA activity under 30 nmol/h.ml were recalled to assess enzyme assay with gold standard and molecular GBA gene analysis on leukocytes.

Results

A total of 73 children (47 boys and 26 girls) were enrolled in this study. GBA activity DBS < 30 nmol/h.ml was found in 18 (23.7%) children among which four (three boys and one girl) were diagnosed as GD with a median age 1.5 years, and the prevalence in this pediatric population was 5.5% (1.5%~ 13.4%). Three new mutations of GBA found in the four GD patients, L264I, A100Cfs*7 and D399E, have not been reported before.

Conclusions

With evaluation of GBA activity on DBS as a preliminary screening method, the diagnostic algorithm used in this study is appropriate to make early diagnosis for GD patients with mild symptoms or atypical symptoms and avoid diagnosis delay.

Trial registration

Not applicable.

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.