Peripheral neuropathy in adult type 1 Gaucher disease: a 2-year prospective observational study

A review of type 3 Gaucher disease: unique neurological manifestations and advances in treatment

Gaucher disease (GD) is a rare lysosomal storage disease that is caused by mutations in the GBA gene. It is classified into three main phenotypes according to the patient's clinical presentation. Of these, chronic neuronopathic GD (GD3) is characterized by progressive neurological damage. Understanding the unique neurological manifestations of GD3 has important diagnostic and therapeutic implications. Our article summarizes the neurological symptoms specific to GD3 and related therapeutic advances, and it highlights the relevance of the gene to clinical symptoms, so as to provide a reference for the diagnosis and treatment of GD3.

Exploring the efficacy and safety of Ambroxol in Gaucher disease: an overview of clinical studies

Gaucher disease (GD) is mainly caused by glucocerebrosidase (GCase) enzyme deficiency due to genetic variations in the GBA1 gene leading to the toxic accumulation of sphingolipids in various organs, which causes symptoms such as anemia, thrombocytopenia, hepatosplenomegaly, and neurological manifestations. GD is clinically classified into the non-neuronopathic type 1, and the acute and chronic neuronopathic forms, types 2 and 3, respectively. In addition to the current approved GD medications, the repurposing of Ambroxol (ABX) has emerged as a prospective enzyme enhancement therapy option showing its potential to enhance mutated GCase activity and reduce glucosylceramide accumulation in GD-affected tissues of different GBA1 genotypes. The variability in response to ABX varies across different variants, highlighting the diversity in patients' therapeutic outcomes. Its oral availability and safety profile make it an attractive option, particularly for patients with neurological manifestations. Clinical trials are essential to explore further ABX's potential as a therapeutic medication for GD to encourage pharmaceutical companies' investment in its development. This review highlights the potential of ABX as a pharmacological chaperone therapy for GD and stresses the importance of addressing response variability in clinical studies to improve the management of this rare and complex disorder.

A zebrafish model of combined saposin deficiency identifies acid sphingomyelinase as a potential therapeutic target

Sphingolipidoses are a subcategory of lysosomal storage diseases (LSDs) caused by mutations in enzymes of the sphingolipid catabolic pathway. Like many LSDs, neurological involvement in sphingolipidoses leads to early mortality with limited treatment options. Given the role of myelin loss as a major contributor toward LSD-associated neurodegeneration, we investigated the pathways contributing to demyelination in a CRISPR-Cas9-generated zebrafish model of combined saposin (psap) deficiency. psap knockout (KO) zebrafish recapitulated major LSD pathologies, including reduced lifespan, reduced lipid storage, impaired locomotion and severe myelin loss; loss of myelin basic protein a (mbpa) mRNA was progressive, with no changes in additional markers of oligodendrocyte differentiation. Brain transcriptomics revealed dysregulated mTORC1 signaling and elevated neuroinflammation, where increased proinflammatory cytokine expression preceded and mTORC1 signaling changes followed mbpa loss. We examined pharmacological and genetic rescue strategies via water tank administration of the multiple sclerosis drug monomethylfumarate (MMF), and crossing the psap KO line into an acid sphingomyelinase (smpd1) deficiency model. smpd1 mutagenesis, but not MMF treatment, prolonged lifespan in psap KO zebrafish, highlighting the modulation of acid sphingomyelinase activity as a potential path toward sphingolipidosis treatment.

Novel Therapeutic Approaches in Inherited Neuropathies: A Systematic Review

The management of inherited neuropathies relies mostly on the treatment of symptoms. In recent years, a better understanding of the pathogenic mechanisms that underlie neuropathies has allowed for the development of disease-modifying therapies. Here, we systematically review the therapies that have emerged in this field over the last five years. An updated list of diseases with peripheral neuropathy as a clinical feature was created based on panels of genes used clinically to diagnose inherited neuropathy. This list was extended by an analysis of published data by the authors and verified by two experts. A comprehensive search for studies of human patients suffering from one of the diseases in our list yielded 28 studies that assessed neuropathy as a primary or secondary outcome. Although the use of various scales and scoring systems made comparisons difficult, this analysis identified diseases associated with neuropathy for which approved therapies exist. An important finding is that the symptoms and/or biomarkers of neuropathies were assessed only in a minority of cases. Therefore, further investigation of treatment efficacy on neuropathies in future trials must employ objective, consistent methods such as wearable technologies, motor unit indexes, MRI or sonography imaging, or the use of blood biomarkers associated with consistent nerve conduction studies.

Case report: Multidisciplinary collaboration in diagnosis and treatment of child gaucher disease

Gaucher disease (GD) is an inherited lysosomal storage disease caused by mutations in the glucocerebrosidase gene. The decrease of glucocerebrosidase activity in lysosomes results in the accumulation of its substrate glucocerebroside in the lysosomes of macrophages in organs such as the liver, spleen, bones, lungs, brain and eyes, and the formation of typical storage cells, namely "Gaucher cells", leading to lesions in the affected tissues and organs. Hepatosplenomegaly, bone pain, cytopenia, neurological symptoms, and other systemic manifestations are common in clinical practice. Most pediatric patients have severe symptoms. Early diagnosis and treatment are crucial to improve the curative effect and prognosis. However, due to the low incidence of this disease, multi-system involvement in patients, and diverse clinical manifestations, multidisciplinary teamwork is needed for comprehensive evaluation, diagnosis and treatment. In this study, we reported 2 cases of different types of GD who were diagnosed, treated and followed up by multidisciplinary collaboration in infancy.

Hemostatic Abnormalities in Gaucher Disease: Mechanisms and Clinical Implications

Gaucher disease (GD) is a rare inherited lysosomal metabolism disorder, characterized by an accumulation into lysosomes of reticuloendothelial cells, especially in the bone marrow, spleen, and liver of β-glucosylceramide and glucosyl sphingosine, which is its deacylated product. Impaired storage is responsible for a chronic inflammatory state at the sites of accumulation and together represents the pathophysiological cause of GD. GD is a progressive, multi-organ chronic disorder. Type 1 GD is the most prevalent form, with heterogeneous multisystem involvement and different severity of symptoms at any age. Hematological involvement is consistent, and a bleeding tendency is frequent, particularly at diagnosis. Several coagulation and primary hemostasis abnormalities are observed in GD. Bleeding manifestations are rarely severe and usually mucocutaneous. Post-operative, delivery, and post-partum hemorrhages are also common. Thrombocytopenia, platelet function defects, and clotting abnormalities, alone or variably associated, contribute to increase the risk of bleeding in GD. Enzyme replacement therapy (ERT) or substrate reduction therapy (SRT) are the two specific available treatments effective in improving typical hematological symptoms and abnormalities, including those of hemostasis. However, the use of medication to potentiate hemostasis may be also useful in defined clinical situations: recent starting of ERT/SRT, surgery, delivery, and life-threatening bleeding.

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.

Update on Neuropathies in Inborn Errors of Metabolism

Neuropathies are relatively common in inborn errors of metabolism (IEMs); however, due to the early onset and severe, progressive course of many IEMs, they have not been very well researched yet. This article aims to review and compare neuropathies in inborn errors of metabolism, mostly with childhood and juvenile onset. Some of these diseases are treatable if diagnosed early and in many cases, the therapy can not only slow down disease progression, but can also reverse the changes already made by the condition.

Prodromal sensory neuropathy in Pink1-/- SNCAA53T double mutant Parkinson mice

AIMS

Parkinson's disease (PD) is frequently associated with a prodromal sensory neuropathy manifesting with sensory loss and chronic pain. We have recently shown that PD-associated sensory neuropathy in patients is associated with high levels of glucosylceramides. Here, we assessed the underlying pathology and mechanisms in Pink1^-/- SNCA^A53T double mutant mice.

METHODS

We studied nociceptive and olfactory behaviour and the neuropathology of dorsal root ganglia (DRGs), including ultrastructure, mitochondrial respiration, transcriptomes, outgrowth and calcium currents of primary neurons, and tissue ceramides and sphingolipids before the onset of a PD-like disease that spontaneously develops in Pink1^-/- SNCA^A53T double mutant mice beyond 15 months of age.

RESULTS

Similar to PD patients, Pink1^-/- SNCA^A53T mice developed a progressive prodromal sensory neuropathy with a loss of thermal sensitivity starting as early as 4 months of age. In analogy to human plasma, lipid analyses revealed an accumulation of glucosylceramides (GlcCer) in the DRGs and sciatic nerves, which was associated with pathological mitochondria, impairment of mitochondrial respiration, and deregulation of transient receptor potential channels (TRPV and TRPA) at mRNA, protein and functional levels in DRGs. Direct exposure of DRG neurons to GlcCer caused transient hyperexcitability, followed by a premature decline of the viability of sensory neurons cultures upon repeated GlcCer application.

CONCLUSIONS

The results suggest that pathological GlcCer contribute to prodromal sensory disease in PD mice via mitochondrial damage and calcium channel hyperexcitability. GlcCer-associated sensory neuron pathology might be amenable to GlcCer lowering therapeutic strategies.

Interstitial lung disease in lysosomal storage disorders

Lysosomes are intracellular organelles that are responsible for degrading and recycling macromolecules. Lysosomal storage diseases (LSDs) are a group of inherited diseases caused by mutations affecting genes that encode the function of the lysosomal enzymes. Three LSDs are associated with lung involvement and/or interstitial lung disease (ILD): Gaucher disease (GD); Niemann-Pick disease, also known as acid sphingomyelinase deficiency (ASMD); and Fabry disease (FD). In GD and in ASMD, analysis of bronchoalveolar lavage fluid and lung biopsy can be informative, showing foamy cells. In GD, ILD is rare. Enzyme replacement therapy (ERT) has been available since 1991 and has greatly changed the natural history of GD, with pulmonary failure and death reported before the ERT era. In ASMD, ILD is frequent and is usually associated with spleen enlargement, low platelet cell count and low level of high-density lipoprotein-cholesterol. Results of ERT are promising regarding preliminary results of olipudase alfa in paediatric and adult ASMD populations. The most frequent respiratory manifestation in FD is COPD-like symptoms regardless of smoking habit and dyspnoea due to congestive heart failure. Early diagnosis of these three LSDs is crucial to prevent irreversible organ damage. Early initiation of ERT can, at least in part, prevent organ failure.

Eye movement biomarkers allow for the definition of phenotypes in Gaucher Disease

BACKGROUND

Neurological forms of Gaucher disease, the inherited disorder of β-Glucosylceramidase caused by bi-allelic variants in GBA1, is a progressive disorder which lacks a disease-modifying therapy. Systemic manifestations of disease are effectively treated with enzyme replacement therapy, however, molecules which cross the blood-brain barrier are still under investigation. Clinical trials of such therapeutics require robust, reproducible clinical endpoints to demonstrate efficacy and clear phenotypic definitions to identify suitable patients for inclusion in trials. The single consistent clinical feature in all patients with neuronopathic disease is the presence of a supranuclear saccadic gaze palsy, in the presence of Gaucher disease this finding serves as diagnostic of 'type 3' Gaucher disease.

METHODS

We undertook a study to evaluate saccadic eye movements in Gaucher patients and to assess the role of the EyeSeeCam in measuring saccades. The EyeSeeCam is a video-oculography device which was used to run a protocol of saccade measures. We studied 39 patients with non-neurological Gaucher disease (type 1), 21 patients with type 3 (neurological) disease and a series of 35 healthy controls. Mean saccade parameters were compared across disease subgroups.

RESULTS

We confirmed the saccadic abnormality in patients with type 3 Gaucher disease and identified an unexpected subgroup of patients with type 1 Gaucher disease who demonstrated significant saccade parameter abnormalities. These patients also showed subtle neurological findings and shared a GBA1 variant.

CONCLUSIONS

This striking novel finding of a potentially attenuated type 3 Gaucher phenotype associated with a specific GBA1 variant and detectable saccadic abnormality prompts review of current disease classification. Further, this finding highlights the broad spectrum of neuronopathic Gaucher phenotypes relevant when designing inclusion criteria for clinical trials.

Real-world effectiveness of eliglustat in treatment-naïve and switch patients enrolled in the International Collaborative Gaucher Group Gaucher Registry

Eliglustat is a first‐line oral therapy for adults with Gaucher disease type 1 (GD1) with extensive, intermediate, or poor CYP2D6‐metabolizer phenotypes (90% of patients). We report real‐world outcomes after 2 years of eliglustat therapy in the International Collaborative Gaucher Group Gaucher Registry (NCT00358943). As of January 2019, baseline and 2‐year data (±1 year) were available for 231 eliglustat‐treated GD1 patients: 19 treatment‐naïve (zero splenectomized) and 212 ERT patients who switched to eliglustat (36 splenectomized). Most patients (89%) were from the United States, where eliglustat was first approved. In treatment‐naïve patients, mean hemoglobin increased from 12.4 to 13.4 g/dL (P = .004, n = 18), mean platelet count increased from 113 to 156 × 10⁹/L (P < .001, n = 17); mean spleen volume decreased from 7.4 to 3.5 multiples of normal (MN) (P = .02, n = 7); mean liver volume remained normal (n = 7), and median spine Z‐score was unchanged (−1.3 to −1.2, n = 6). In non‐splenectomized switch patients, mean hemoglobin remained stable/non‐anemic (n = 167); mean platelet count remained stable/normal (n = 165); mean spleen volume decreased from 3.3 to 2.8 MN (P < .001, n = 64); mean liver volume remained normal (n = 63), and median lumbar spine Z‐score improved from −0.7 to −0.4 (P = .014, n = 68). In splenectomized switch patients, mean hemoglobin remained stable/non‐anemic (n = 31); mean platelet count increased from 297 to 324 × 10⁹/L (non‐significant, n = 29); mean liver volume remained normal (n = 13); median spine Z‐score improved from −0.8 to −0.6 (non‐significant, n = 11). Median chitotriosidase decreased in all groups (P < .01 for all). These real‐world results are consistent with eliglustat clinical trial results demonstrating long‐term benefit in treatment‐naïve patients and stability in ERT switch patients.

Assessment of cellular cobalamin metabolism in Gaucher disease

BACKGROUND

Gaucher disease (GD) is a lysosomal disorder caused by biallelic pathogenic mutations in the GBA1 gene that encodes beta-glucosidase (GCase), and more rarely, by a deficiency in the GCase activator, saposin C. Clinically, GD manifests with heterogeneous multiorgan involvement mainly affecting hematological, hepatic and neurological axes. This disorder is divided into three types, based on the absence (type I) or presence and severity (types II and III) of involvement of the central nervous system. At the cellular level, deficiency of GBA1 disturbs lysosomal storage with buildup of glucocerebroside. The consequences of disturbed lysosomal metabolism on biochemical pathways that require lysosomal processing are unknown. Abnormal systemic markers of cobalamin (Cbl, B₁₂) metabolism have been reported in patients with GD, suggesting impairments in lysosomal handling of Cbl or in its downstream utilization events.

METHODS

Cultured skin fibroblasts from control humans (n = 3), from patients with GD types I (n = 1), II (n = 1) and III (n = 1) and an asymptomatic carrier of GD were examined for their GCase enzymatic activity and lysosomal compartment intactness. Control human and GD fibroblasts were cultured in growth medium with and without 500 nM hydroxocobalamin supplementation. Cellular cobalamin status was examined via determination of metabolomic markers in cell lysate (intracellular) and conditioned culture medium (extracellular). The presence of transcobalamin (TC) in whole cell lysates was examined by Western blot.

RESULTS

Cultured skin fibroblasts from GD patients exhibited reduced GCase activity compared to healthy individuals and an asymptomatic carrier of GD, demonstrating a preserved disease phenotype in this cell type. The concentrations of total homocysteine (tHcy), methylmalonic acid (MMA), cysteine (Cys) and methionine (Met) in GD cells were comparable to control levels, except in one patient with GD III. The response of these metabolomic markers to supplementation with hydroxocobalamin (HOCbl) yielded variable results. The content of transcobalamin in whole cell lysates was comparable in control human and GD patients.

CONCLUSIONS

Our results indicate that cobalamin transport and cellular processing pathways are overall protected from lysosomal storage damage in GD fibroblasts. Extending these studies to hepatocytes, macrophages and plasma will shed light on cell- and compartment-specific vitamin B₁₂ metabolism in Gaucher disease.

Polyneuropathy in Gaucher disease type 1 and 3 - a descriptive case series

Polyneuropathy (PNP) has been reported to be a possible phenotypic feature in Gaucher disease type 1 (GD1), while less is known about PNP in type 3 (GD3). We performed a cross-sectional study, exploring PNP in a Swedish GD cohort. Clinical assessment and blood biochemistry were carried out in 8 patients with GD1 and 11 patients with GD3. In patients with symptoms or clinical findings indicative of PNP, nerve conduction studies and quantitative sensory testing were performed. Assessments were compared to historic controls. A subclinical small fiber neuropathy (SFN) was demonstrated in 2 of 8 patients in the significantly (p = 0,021) older GD1 cohort. A large fiber PNP was evident in an additional 3 GD1 patients but could not be ascribed as disease manifestation. No GD3 patients exhibited neurophysiological evidence of small or large fiber PNP attributed to GD3. Compared to historic controls, no significant group differences were evident with regard to neuropathy rating scores. In summary, our study does not support large fiber PNP as a prevalent manifestation of GD. SFN is a possible feature in GD1, although small sample size limits definite conclusions. Our study provides novel data, arguing against clinically significant small or large fiber PNP in GD3.

Long-term adverse event profile from four completed trials of oral eliglustat in adults with Gaucher disease type 1

Background

Eliglustat is a first-line oral treatment for adults with Gaucher disease type 1 who have an extensive, intermediate or poor CYP2D6 metabolizer phenotype (> 90% of patients). Whereas enzyme replacement therapy for Gaucher disease has been widely used for more than two decades, eliglustat has only been in commercial use since 2014. Clinicians and patients want to better understand which adverse events are most commonly associated with eliglustat, as well as their severity, frequency, and duration.

Methods

This pooled analysis of treatment-emergent adverse events combines data from four completed eliglustat clinical trials involving 393 Gaucher disease type 1 patients. It represents 1400 patient-years of eliglustat exposure and a mean treatment duration of 3.6 years (maximum: 9.3 years).

Results

Eighty-one percent of patients remained in their respective trial until commercial availability of eliglustat (US patients only) or until trial completion. Nine patients (2.3%) withdrew from their respective trial due to one or more adverse events reported as eliglustat treatment-related; all but one of these events were mild or moderate. Overall, 97% of adverse events were mild or moderate and 86% were reported by the investigator as unrelated to eliglustat treatment. The overall rate of adverse events decreased over time and did not increase with increasing eliglustat dose. We evaluated frequency, duration, and severity of 14 adverse event terms reported at least once as treatment-related in 2% or more of all patients: dyspepsia (5.9%), headache (5.3%), abdominal pain upper (5.1%), dizziness (5.1%), diarrhea (4.6%), nausea (4.6%), arthralgia (3.6%), constipation (3.3%), abdominal pain (2.8%), gastroesophageal reflux disease (2.8%), fatigue (2.8%), palpitations (2.8%), abdominal distension (2.5%), and gastritis (2.3%). For abdominal pain upper, diarrhea, nausea, abdominal pain, and headache events, median duration was less than 14 days. All 14 adverse event terms, except for arthralgia and headache, were reported only once per patient in more than 70% of patients experiencing the event.

Conclusions

This final pooled analysis of treatment-emergent adverse events reinforces the favorable safety profile of eliglustat. The majority of the most frequently reported treatment-related adverse events were mild or moderate, transient, and occurred only once per patient.

Electronic supplementary material

The online version of this article (10.1186/s13023-019-1085-6) contains supplementary material, which is available to authorized users.

Peripheral neural response and sex hormones in type 1 Gaucher disease

Background

In a rare Gaucher disease, reduced activity of lysosomal b-glucocerebrosidase incompletely blocks glucosphingolipid catabolism. Accumulation of the unhydrolyzed substrate glucosylceramide within lysosomes results in progressive, multisystem Gaucher disease, classified into three types. Both parkinsonism and peripheral neuropathy are observed in cases of putative non-neuronopathic type 1 disease. In the current study we investigated whether the peripheral neural response in type 1 Gaucher disease patients, with no neural manifestations is conditioned by the influence of sex hormones.

Methods

The catalytic activity of b-glucocerebrosidase in peripheral blood leukocytes was determined spectrofluorometrically. Direct sequencing of the GBA1 gene was performed. Somatosensory evoked potentials were recorded after electrical stimulation of the median nerve of both arms. Stimuli of 0.2 ms duration at a frequency of 5 Hz were used. Sex hormones were determined by radioimmunoassay using a gamma scintillation counter.

Results

Analysis of the somatosensory evoked potentials revealed significant differences in peak latencies on periphery between men and women in both control and type 1 Gaucher disease groups. Analysis by gender showed significant associations between latencies and sex hormones only in female patients: negative correlation between oestradiol concentration and N9 peak latency, and a strong negative correlation of testosterone levels with all peak latencies on the periphery (N9-N13).

Conclusions

A relationship between testosterone concentrations and the latencies of potentials evoked on peripheral nerves exists only in females with type 1 Gaucher disease. We point out sexual dimorphism in the development of this entity.

Neurological effects of glucocerebrosidase gene mutations

The association between Gaucher disease (GD) and Parkinson disease (PD) has been described for almost two decades. In the biallelic state (homozygous or compound heterozygous) mutations in the glucocerebrosidase gene (GBA) may cause GD, in which glucosylceramide, the sphingolipid substrate of the glucocerebrosidase enzyme (GCase), accumulates in visceral organs leading to a number of clinical phenotypes. In the biallelic or heterozygous state, GBA mutations increase the risk for PD. Mutations of the GBA allele are the most significant genetic risk factor for idiopathic PD, found in 5%–20% of idiopathic PD cases depending on ethnicity. The neurological consequences of GBA mutations are reviewed and the proposition that GBA mutations result in a disparate but connected range of clinically and pathologically related neurological features is discussed. The literature relating to the clinical, biochemical and genetic basis of GBA PD, type 1 GD and neuronopathic GD is considered highlighting commonalities and distinctions between them. The evidence for a unifying disease mechanism is considered.

Corticobasal syndrome in a man with Gaucher disease type 1: Expansion of the understanding of the neurological spectrum

Gaucher disease (GD) is an autosomal recessive condition that results from a deficiency of the enzyme β-glucocerebrosidase. The increased risk of primary parkinsonism symptoms among individuals affected with GD and carriers for the disorder is well-documented in the literature. However, these risks and case reports often reflect patients with classical Parkinson's disease (PD) symptoms. We report a patient with GD type 1 who was diagnosed with corticobasal syndrome (CBS), a clinical atypical parkinsonism diagnosis, in his sixth decade of life. Our case highlights the need to consider forms of atypical parkinsonism such as CBS in addition to PD in the differential diagnosis of cognitive and motor changes in patients with GD type 1. We also recommend careful assessment and routine monitoring of cognition, mood, behavior, sleep patterns, olfaction, and memory in patients with GD type 1 to identify early symptoms indicative of neurological involvement.

Miglustat in Niemann-Pick disease type C patients: a review

OBJECTIVE

Niemann-Pick disease type C (NP-C) is a rare, autosomal recessive, neurodegenerative disease associated with a wide variety of progressive neurological manifestations. Miglustat is indicated for the treatment of progressive neurological manifestations in both adults and children. Since approval in 2009 there has been a vast growth in clinical experience with miglustat. The effectiveness of miglustat has been assessed using a range of measures.

METHODS

Comprehensive review of published data from studies of cellular neuropathological markers and structural neurological indices in the brain, clinical impairment/disability, specific clinical neurological manifestations, and patient survival.

RESULTS

Cranial diffusion tensor imaging and magnetic resonance spectroscopy studies have shown reduced levels of choline (a neurodegeneration marker), and choline/N-acetyl aspartate ratio (indicating increased neuronal viability) in the brain during up to 5 years of miglustat therapy, as well as a slowing of reductions in fractional anisotropy (an axonal/myelin integrity marker). A 2-year immunoassay study showed significant reductions in CSF-calbindin during treatment, indicating reduced cerebellar Purkinje cell loss. Magnetic resonance imaging studies have demonstrated a protective effect of miglustat on cerebellar and subcortical structure that correlated with clinical symptom severity. Numerous cohort studies assessing core neurological manifestations (impaired ambulation, manipulation, speech, swallowing, other) using NP-C disability scales indicate neurological stabilization over 2-8 years, with a trend for greater benefits in patients with older (non-infantile) age at neurological onset. A randomized controlled trial and several cohort studies have reported improvements or stabilization of saccadic eye movements during 1-5 years of therapy. Swallowing was also shown to improve/remain stable during the randomized trial (up to 2 years), as well as in long-term observational cohorts (up to 6 years). A meta-analysis of dysphagia - a potent risk factor for aspiration pneumonia and premature death in NP-C - demonstrated a survival benefit with miglustat due to improved/stabilized swallowing function.

CONCLUSIONS

The effects of miglustat on neurological NP-C manifestations has been assessed using a range of approaches, with benefits ranging from cellular changes in the brain through to visible clinical improvements and improved survival.

Chronic pain in Gaucher disease: skeletal or neuropathic origin?

Backgound

Pain is one of the most disabling symptoms of Gaucher disease. It is referred by the majority of Gaucher patients and often persists despite long-term enzyme replacement treatment. It has been mainly considered as nociceptive pain secondary to skeletal involvement but it is described even in the absence of bone disease without a clear explanation. In the last years an increasing number of reports have described the presence of neurological manifestation in Gaucher type 1 patients, including subclinical large fibre neuropathy. In our Gaucher clinic we have observed the recurrence of painful symptoms in a group of type 1 Gaucher patients even after a long-term enzyme replacement therapy.

Methods

A cross-sectional study was designed to investigate the pathophysiology of pain in a cohort of 25 Gaucher patients (13 females, 12 males). Twenty-two patients received enzyme replacement therapy for a period of time ranging from 10 to >20 years, while three were new diagnosis. Pain was classified as bone or neurologic related on the basis of anamnestic data, clinical and electrophysilogical examinations. Intensity and quality of pain were recorded by Douleur Neuropathique en 4 questionnaire and Neuropathic Pain Symptom Inventory. Neuroalgological evaluation, quantitative sensory testing, nerve conduction studies and evaluation of epidermal nerve fibres density were performed. Comorbidities for peripheral neuropathy were excluded.

Results

Thirteen patients complained of pain suggestive of neuropathic origin with proximal patchy distribution, six manifested severe pain paroxysmal, nine pinprick hypoesthesia and 17 thermal hypoesthesia. At quantitative sensory testing, all of them showed high cold thresholds with errata sensation (burning instead of cold), paradoxical heat sensation and mechanic hypoesthesia; three patients showed pressure pain hyperalgesia. Epidermal denervation was present in 19 patients, 12 of them with non-length dependent pattern.

Conclusions

These results confirm the role of peripheral neuropathy in Gaucher pain and demonstrate that skin denervation is as a constitutive feature of the disorder. In addition, they further confirm the existence of a continuum Gaucher phenotype, and provide a new interpretation of pain origin that should be considered for an appropriate disease management and to avoid unnecessary dose escalations of enzyme therapy.

A Review of Gaucher Disease Pathophysiology, Clinical Presentation and Treatments

Gaucher disease (GD, ORPHA355) is a rare, autosomal recessive genetic disorder. It is caused by a deficiency of the lysosomal enzyme, glucocerebrosidase, which leads to an accumulation of its substrate, glucosylceramide, in macrophages. In the general population, its incidence is approximately 1/40,000 to 1/60,000 births, rising to 1/800 in Ashkenazi Jews. The main cause of the cytopenia, splenomegaly, hepatomegaly, and bone lesions associated with the disease is considered to be the infiltration of the bone marrow, spleen, and liver by Gaucher cells. Type-1 Gaucher disease, which affects the majority of patients (90% in Europe and USA, but less in other regions), is characterized by effects on the viscera, whereas types 2 and 3 are also associated with neurological impairment, either severe in type 2 or variable in type 3. A diagnosis of GD can be confirmed by demonstrating the deficiency of acid glucocerebrosidase activity in leukocytes. Mutations in the GBA1 gene should be identified as they may be of prognostic value in some cases. Patients with type-1 GD-but also carriers of GBA1 mutation-have been found to be predisposed to developing Parkinson's disease, and the risk of neoplasia associated with the disease is still subject to discussion. Disease-specific treatment consists of intravenous enzyme replacement therapy (ERT) using one of the currently available molecules (imiglucerase, velaglucerase, or taliglucerase). Orally administered inhibitors of glucosylceramide biosynthesis can also be used (miglustat or eliglustat).

Impaired gait kinematics in type 1 Gaucher's Disease

Type 1 Gaucher's disease (GD1) is traditionally regarded as "non-neurological". Spatiotemporal and kinematic analysis of gait was carried on thirteen GD1 patients and thirteen healthy controls. We identified a previously unknown subclinical reduction of amplitude of movements in GD1. Articular excursion of ankle, knee and hip was reduced during the swing phase of gait (p <  0.0001). Furthermore, the excursion of the knee appeared also significantly more asymmetric in GD1 patients (p = 0.02). Correction for age, BMI and basal walking speed did not modify the significance. Accordingly to the recent observations that GD1 predisposes to Parkinson's disease, the impaired and asymmetric gait kinematics that we observed might be interpreted as a form of extrapyramidal involvement.

Long-term hematological, visceral, and growth outcomes in children with Gaucher disease type 3 treated with imiglucerase in the International Collaborative Gaucher Group Gaucher Registry

In Gaucher disease (GD), deficiency of lysosomal acid β-glucosidase results in a broad phenotypic spectrum that is classified into three types based on the absence (type 1 [GD1]) or presence and severity of primary central nervous system involvement (type 2 [GD2], the fulminant neuronopathic form, and type 3 [GD3], the milder chronic neuronopathic form). Enzyme replacement therapy (ERT) with imiglucerase ameliorates and prevents hematological and visceral manifestations in GD1, but data in GD3 are limited to small, single-center series. The effects of imiglucerase ERT on hematological, visceral and growth outcomes (note: ERT is not expected to directly impact neurologic outcomes) were evaluated during the first 5years of treatment in 253 children and adolescents (<18years of age) with GD3 enrolled in the International Collaborative Gaucher Group (ICGG) Gaucher Registry. The vast majority of GBA mutations in this diverse global population consisted of only 2 mutations: L444P (77%) and D409H (7%). At baseline, GD3 patients exhibited early onset of severe hematological and visceral disease and growth failure. During the first year of imiglucerase treatment, hemoglobin levels and platelet counts increased and liver and spleen volumes decreased, leading to marked decreases in the number of patients with moderate or severe anemia, thrombocytopenia, and hepatosplenomegaly. These improvements were maintained through Year 5. There was also acceleration in linear growth as evidenced by increasing height Z-scores. Despite devastating disease at baseline, the probability of surviving for at least 5years after starting imiglucerase was 92%. In this large, multinational cohort of pediatric GD3 patients, imiglucerase ERT provided a life-saving and life-prolonging benefit for patients with GD3, suggesting that, with proper treatment, many such severely affected patients can lead productive lives and contribute to society.

Rare Case of Hepatic Gaucheroma in a Child on Enzyme Replacement Therapy

BACKGROUND

We present a 6 year old boy with type I Gaucher treated from 16 months with ERT, developing focal Gaucheroma in the liver at 3.5 years.

CASE

The subject presented at 13 months of age with anaemia, thrombocytopenia and hepatosplenomegaly. Gaucher disease was confirmed by leucocyte enzyme assay. A homozygous change: c.1193G>A (p.Arg398Gln) in the GBA gene was identified. He had normal neurology with normal saccades. Imiglucerase was administered at 60 IU/kg/fortnight from 15 months as per Australian regulations with good clinical response. At 3.5 years hepatic ultrasound demonstrated a nodular cystic lesion measuring 7 × 5.3 × 5.1 cm in the right lobe of liver, confirmed on MRI. Biopsy demonstrated acellular hyaline necrosis, portal-portal bridging fibrosis and nodules of Gaucher cells. Cystic fluid comprised necrotic debris and Gaucher cells. Further evaluation over 18 months including repeat MRI, biopsy, alpha-fetoprotein monitoring and whole-body FDG-Pet scan demonstrate no malignancy.

CONCLUSION

GD is the most common lysosomal storage disorder. The aetiology, natural history and optimal management strategy of rare Gaucheroma in paediatric cases has not been defined particularly in regards to malignancy risk.

Comorbidities and pharmacotherapies in patients with Gaucher disease type 1: The potential for drug-drug interactions

PURPOSE

Clinical care for patients with rare diseases may be complicated by comorbidities. Administration of medications to treat comorbidities may elicit potentially harmful drug-drug interactions (DDIs). Genetic background may also influence DDI occurrence. We investigated the range of comorbid conditions in patients with Gaucher disease type I (GD1), the pharmacotherapies prescribed and the potential for DDI with enzyme replacement and substrate reduction therapies and additional medications, specifically cytochrome P450 (CYP) metabolizing medications.

METHODS

A literature review examined comorbid conditions and pharmacotherapies reported in GD1. Analysis of two national databases reported real-world prescription practices in patients with GD1 (Germany, N=87; US, N=374). Prescribed drugs were assessed for known interactions with isoenzymes from the hepatic CYP enzyme family.

RESULTS

The literature reported GD1 symptomatology and comorbid conditions in broad agreement with the known clinical picture. German patients received 86 different medications whereas US patients received 329 different medications. An average of 3.2 medications (Germany) and 7 medications (US) per patient were prescribed. Moderate/strong inhibitors of CYP isoenzymes were prescribed to 20% and 57% of patients in the US and Germany, respectively.

CONCLUSION

This study describes the extensive number of comorbid conditions and drugs prescribed to patients with GD1, and the importance of determining CYP isoenzyme interaction to reduce DDI risk.

Peripheral neuropathy and parkinsonism: a large clinical and pathogenic spectrum

Peripheral neuropathy (PN) has been reported in idiopathic and hereditary forms of parkinsonism, but the pathogenic mechanisms are unclear and likely heterogeneous. Levodopa-induced vitamin B12 deficiency has been discussed as a causal factor of PN in idiopathic Parkinson's disease, but peripheral nervous system involvement might also be a consequence of the underlying neurodegenerative process. Occurrence of PN with parkinsonism has been associated with a panel of mitochondrial cytopathies, more frequently related to a nuclear gene defect and mainly polymerase gamma (POLG1) gene. Parkin (PARK2) gene mutations are responsible for juvenile parkinsonism, and possible peripheral nervous system involvement has been reported. Rarely, an association of parkinsonism with PN may be encountered in other neurodegenerative diseases such as fragile X-associated tremor and ataxia syndrome related to premutation CGG repeat expansion in the fragile X mental retardation (FMR1) gene, Machado-Joseph disease related to an abnormal CAG repeat expansion in ataxin-3 (ATXN3) gene, Kufor-Rakeb syndrome caused by mutations in ATP13A2 gene, or in hereditary systemic disorders such as Gaucher disease due to mutations in the β-glucocerebrosidase (GBA) gene and Chediak-Higashi syndrome due to LYST gene mutations. This article reviews conditions in which PN may coexist with parkinsonism.

Gaucher disease and comorbidities: B-cell malignancy and parkinsonism

Data emerging from the International Collaborative Gaucher Group (ICGG) Gaucher Registry together with other contemporary clinical surveys have revealed a close association between Gaucher disease and non-Hodgkin's B-cell lymphoma and myeloma and Gaucher disease and Parkinson's disease. Several possible explanations for increased B-cell proliferation and neoplasia in Gaucher disease have been proposed, including the possible influence of sphingosine (derived from the extra lysosomal metabolism of glucosylceramide), gene modifiers, splenectomy and immune system deregulation induced by cytokines, chemokines, and hydrolases released from Gaucher cells. Parkinson's disease is frequently seen in the otherwise-healthy relatives of Gaucher disease patients leading to the finding that GBA mutations represent a genetic risk factor for Parkinson's disease. The mechanism of the association between GBA mutations and Parkinson's disease has yet to be elucidated but the pathogenesis appears distinct from that of Gaucher disease. Several pathogenic pathways have been proposed including lysosomal and/or mitochondrial dysfunction. The effect of Gaucher disease specific therapies on the incidence of cancer or Parkinson's disease are not clear and will likely be evaluated in future ICGG Gaucher Registry studies.

Understanding the natural history of Gaucher disease

Gaucher disease is a rare and extraordinarily heterogeneous inborn error of metabolism that exhibits diverse manifestations, a broad range of age of onset of symptoms, and a wide clinical spectrum of disease severity, from lethal disease during infancy to first age of onset of symptoms in octogenarians. Before the advent of the International Collaborative Gaucher Group (ICGG) Gaucher Registry, the understanding of the natural history and phenotypic range of Gaucher disease was based on isolated case reports and small case series. Limited data hindered understanding of the full spectrum of the disease leading to some early misconceptions about Gaucher disease, notably, that nonneuronopathic (type 1) disease was a disease of adults only. The global scope of the ICGG Gaucher Registry, with its vast body of longitudinal data, has enabled a real appreciation of both the phenotypic spectrum of Gaucher disease and its natural history. This body of evidence represents the foundation for accurate assessment of the response to specific therapies for Gaucher disease and to the development of standard-of-care to monitor disease activity. Here, we outline the key developments in delineating the natural history of this highly complex disease and role of the ICGG Gaucher Registry in this effort.

Switching from imiglucerase to miglustat for the treatment of French patients with Gaucher disease type 1: a case series

Introduction

Gaucher disease is caused by a deficiency of the enzyme β-glucocerebrosidase. Treatment with enzyme replacement therapy has been available for the past two decades but, although effective, enzyme replacement therapy can be delivered only by intravenous infusion every other week. The oral substrate reduction therapy miglustat (Zavesca®) has been available in Europe since 2002 for the treatment of patients with mild or moderate Gaucher disease type 1 for whom enzyme replacement therapy is unsuitable or not a therapeutic option. There are few published real-world data on the use of miglustat as a maintenance therapy in Gaucher disease type 1 patients switched from previous enzyme replacement therapy. We report a case series of three patients who were switched from long-term enzyme replacement therapy to miglustat for various reasons.

Case presentation

All three patients were Caucasian and had confirmed Gaucher disease type 1. An 80-year-old man requested a switch to oral miglustat therapy in preference to ongoing intravenous enzyme replacement therapy, a 57-year-old woman was commenced on miglustat due to a shortage of imiglucerase, and a 56-year-old woman was switched from previous enzyme replacement therapy due to allergic reactions to intravenous infusions. Hematological disease parameters were stable in each patient on previous enzyme replacement therapy. Two patients continue to be treated with miglustat, having shown good tolerability and stable core disease parameters for approximately 4 years. One patient, who was also stable during 7 years of therapy, eventually discontinued miglustat as a precaution because he developed peripheral neuropathy of as yet unknown origin.

Conclusions

Overall, our experience indicates that miglustat can be used as maintenance therapy for Gaucher disease type 1 after initial enzyme replacement therapy, but the selection of patients to whom this approach should be applied should be made after careful consideration of all disease parameters.

Enzyme replacement and substrate reduction therapy for Gaucher disease

BACKGROUND

Gaucher disease, a rare disorder, is caused by inherited deficiency of the enzyme glucocerebrosidase. It is unique among the ultra-orphan disorders in that four treatments are currently approved by various regulatory authorities for use in routine clinical practice. Hitherto, because of the relatively few people affected worldwide, many of whom started therapy during a prolonged period when there were essentially no alternatives to imiglucerase, these treatments have not been systematically evaluated in studies such as randomized controlled trials now considered necessary to generate the highest level of clinical evidence.

OBJECTIVES

To summarize all available randomized controlled study data on the efficacy and safety of enzyme replacement therapies and substrate reduction therapy for treating Gaucher disease.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Inborn Errors of Metabolism Trials Register. Additional searches were conducted on ClinicalTrials.gov for any ongoing studies with potential interim results, and through PubMed. We also searched the reference lists of relevant articles and reviews.Date of last search: 07 August 2014.

SELECTION CRITERIA

All randomized and quasi-randomized controlled studies (including open-label studies and cross-over studies) assessing enzyme replacement therapy or substrate reduction therapy, or both, in all types of Gaucher disease were included.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed the risk of bias in the included studies, and extracted relevant data.

MAIN RESULTS

Of the 488 studies retrieved by the electronic searches, eight met the inclusion criteria and were analysed (300 participants). Response parameters were restricted to haemoglobin concentration, platelet count, spleen and liver volume and serum biomarkers (chitotriosidase and CCL18). Only one publication reported a 'low risk of bias' score in all parameters assessed, and all studies included were randomized.Four studies reported the responses to enzyme replacement therapy of previously untreated individuals with type 1 Gaucher disease. Two studies investigated maintenance enzyme replacement therapy in people with stable type 1 Gaucher disease previously treated for at least two years. One study compared substrate reduction therapy, enzyme replacement therapy and a combination thereof as maintenance therapy in people with type 1 Gaucher disease previously treated with enzyme replacement therapy. One study examined substrate reduction therapy in people with chronic neuronopathic (type 3) Gaucher disease who continued to receive enzyme replacement therapy.Treatment-naïve participants had similar increases in haemoglobin when comparing those receiving imiglucerase or alglucerase at 60 units/kg, imiglucerase or velaglucerase alfa at 60 U/kg, taliglucerase alfa at 30 units/kg or 60 units/kg, and velaglucerase alfa at 45 units/g or 60 units/kg. For platelet count response in participants with intact spleens, a benefit for imiglucerase over velaglucerase alfa at 60 units/kg was observed, mean difference -79.87 (95% confidence interval -137.57 to -22.17). There were no other significant differences in platelet count response when comparing different doses of velaglucerase alfa and of taliglucerase alfa, and when comparing imiglucerase to alglucerase. Spleen and liver volume reductions were not significantly different in any enzyme replacement therapy product or dose comparison study. Although a dose effect on serum biomarkers was not seen after nine months, a significantly greater reduction with higher dose was reported after 12 months in the velaglucerase study, mean difference 16.70 (95% confidence intervaI 1.51 to 31.89). In the two enzyme replacement therapy maintenance studies comparing infusions every two weeks and every four weeks, there were no significant differences in haemoglobin concentration, platelet count, and spleen and liver volumes over a 6 to 12 month period when participants were treated with the same cumulative dose.A total of 25 serious adverse events were reported, nearly all deemed unrelated to treatment.There are, as yet, no randomized trials of substrate reduction therapy in treatment-naïve patients that can be evaluated. Miglustat monotherapy appeared as effective as continued enzyme replacement therapy for maintenance of hematological, organ and biomarker responses in people with type 1 Gaucher disease previously treated with imiglucerase for at least two years. In those with neuronopathic Gaucher disease, no significant improvements in haemoglobin concentration, platelet count or organ volumes occurred when enzyme replacement therapy was augmented with miglustat.One randomized controlled study assessing substrate reduction therapy was published immediately prior to producing the final version of this review, and this, along with a further ongoing study (expected to be published in the near future), will be assessed for eligibility in a future update of the review.

AUTHORS' CONCLUSIONS

The results reflect the limitations of analysing evidence restricted to prospective randomized controlled trials, especially when dealing with chronic rare diseases. This analysis suggests that, during the first year of treatment, different recombinant glucocerebrosidases are bio-similar and non-inferior in safety and efficacy for surrogate biological response parameters. Enzyme replacement therapy given at 30 to 45 units/kg body weight every two to four weeks was generally as effective as the 60 unit/kg dose for the assessed clinical outcomes. The analysis emphasise the need to determine whether it is realistic to carry out multi-decade prospective clinical trials for rare diseases such as type 1 Gaucher disease. With large treatment effects on the classical manifestations of the disorder, therapeutic investigations in Gaucher disease mandate innovative trial designs and methodology to secure decisive data concerning long-term efficacy and safety - with the realization that knowledge about disease-modifying actions that are sustained are of crucial importance to people with this chronic condition.

The attenuated/late onset lysosomal storage disorders: Therapeutic goals and indications for enzyme replacement treatment in Gaucher and Fabry disease

Enzyme replacement therapies have been developed and authorized for commercial use for six different lysosomal storage disorders. For Gaucher disease, Fabry disease and mucopolysaccharidosis type 1, disease-specific treatments have been available for more than a decade. Although long term follow-up data are still sparse, therapeutic goals for patients with Gaucher disease and Fabry disease have been formulated and published for both adults and children. Without adaptation or modification, these goals are often applied in clinical research and in routine patient care across the entire phenotypic spectrum of disease, although in practice, patients commonly manifest high variability in clinical presentation and course of the illness. In this context, establishing goals for the follow-up and treatment of late onset/attenuated phenotypes is particularly challenging. In this chapter, we review current therapeutic goals for Gaucher disease and Fabry disease and discuss approaches for those with attenuated disease manifestations.

Results from a 9-year Intensive Safety Surveillance Scheme (IS(3) ) in miglustat (Zavesca(®) )-treated patients

BACKGROUND

Following approval in the EU in 2002 and the USA in 2003, an Intensive Safety Surveillance Scheme (IS(3) ) was initiated to educate prescribers on the appropriate use of miglustat for the treatment of type I Gaucher disease (GD1), and to actively solicit safety-relevant information. This report summarises data from all patients enrolled in IS(3) between its initiation in 2003 and its closure in October 2012.

METHODS

The IS(3) was a prospective observational drug registry with a secure internet-based data capture system. All patients receiving miglustat at participating sites received standard medical care according to routine medical practice. Data on patient and disease characteristics were collected at patient enrolment, subsequent follow-up visits and treatment discontinuation (if applicable). Data were summarised using descriptive statistics.

RESULTS

During the 9 years of IS(3) , 407 patients were enrolled at 111 sites across 15 European countries. Approximately half (n = 202) had GD1, and half had other diseases (mainly Niemann-Pick disease type C (NP-C), for which miglustat was approved in Europe in 2009). In total, 368 patients had data from at least one follow-up visit, 192 of whom had GD1. IS(3) provided data from 798 patient-years exposure to miglustat. Safety-relevant data were consistent with earlier published 5-year findings from IS(3) , the safety profile reported for miglustat in GD1 clinical trials and other published information on GD1 manifestations.

CONCLUSIONS

Overall, the results of this long-term safety surveillance programme were in line with the well-known, documented safety profile of miglustat.

Long-term effectiveness of enzyme replacement therapy in children with Gaucher disease: results from the NCS-LSD cohort study

OBJECTIVES

To determine the effectiveness of enzyme replacement therapies (ERT) for children with Gaucher disease (GD).

DESIGN

A longitudinal cohort study including prospective and retrospective clinical data. Age- and gender-adjusted treatment effects were estimated using generalised linear mixed models. Children on treatment contributed data before and during treatment. Children not on treatment contributed natural history data.

PARTICIPANTS

Consenting children (N = 25, aged 1.1 to 15.6 years) with a diagnosis of GD (14 with GD1 and 11 with GD3) who attended a specialist treatment centre in England. At recruitment, 24 patients were receiving ERT (mean treatment duration, 5.57 years; range 0-13.7 years).

OUTCOME MEASURES

Clinical outcomes chosen to reflect disease progression, included platelet count; haemoglobin and absence/presence of bone pain.

RESULTS

Duration of ERT was associated with statistically significant improvements in platelet count (p < 0.001), haemoglobin (p < 0.001), and reported bone pain (p = 0.02). The magnitude of effect on haematological parameters was greater in children with GD3 than in those with GD1.

CONCLUSIONS

These data provide further evidence of the long-term effectiveness of ERT in children with GD.

Long-term effectiveness of enzyme replacement therapy in adults with Gaucher disease: results from the NCS-LSD cohort study

OBJECTIVES

To determine the effectiveness of enzyme replacement therapies (ERT) for adults with Gaucher disease (GD).

DESIGN

A longitudinal, multi-centre cohort study, including prospective and retrospective clinical data. Age- and gender-adjusted treatment effects were estimated using generalised linear mixed models. Treated patients contributed data before and during treatment. Untreated patients contributed natural history data.

PARTICIPANTS

Consenting adults (N = 150, aged 16 to 83 years) with a diagnosis of GD who attended a specialist treatment centre in England. At recruitment, 131 patients were receiving ERT (mean treatment duration, 10.8 years; range 0-18 years).

OUTCOME MEASURES

Clinical outcomes chosen to reflect disease progression, included platelet count; haemoglobin; absence/presence of bone pain; spleen and liver volumes and AST levels.

RESULTS

One hundred and fifty adults were recruited. Duration of ERT was associated with statistically significant improvements in platelet count (p < 0.001), haemoglobin (p < 0.001), liver and spleen volumes (p < 0.001) and AST levels (p = 0.02).

CONCLUSIONS

These data provide further evidence of the long-term effectiveness of ERT in adults with GD.

The European Gaucher Alliance: a survey of member patient organisations' activities, healthcare environments and concerns

Background

The European Gaucher Alliance (EGA) was established in 1994 and constituted in 2008 as an umbrella group supporting patient organisations for Gaucher disease. Every two years, the EGA conducts a questionnaire survey of member associations to help develop its priorities and annual work programme. Results of the latest survey are presented.

Methods

Between June 2012 and April 2013, the 36 members and associate members of the EGA were asked to complete a questionnaire detailing membership numbers, disease specific treatments used by patients, means of access to treatment, availability of treatment centres and home infusions, sources of support for patients with Gaucher disease, patient organisations’ activities, collaborations, funding sources and any issues of concern. Questionnaires completed in 2012 were revised in January 2013 and responses analysed between July and September 2013.

Results

Thirty three members returned data on one or more questions. Findings identified inequalities in access to treatment both within and between members’ countries. Three of 27 countries, for which data were available, relied totally on humanitarian aid for treatment and 6% of untreated patients in 20 countries were untreated because of funding issues, a situation many feared would worsen with deteriorating economic climates. Access to treatment and reimbursement represented 45% of members’ concerns, while 35% related to access to specialist treatment centres, home infusions and doctors with expertise in Gaucher disease. Member associations’ main activities centred on patient support (59% of responses) and raising awareness of Gaucher disease and patients’ needs amongst the medical community, government and healthcare decision makers and the general public (34% of responses). Twenty one (78% of respondents) indicated they were the only source of help for Gaucher disease patients in their country. For many, activities were constrained by funds; two members had no external funding source. Activities were maximised through collaboration with other patient organisations and umbrella organisations for rare diseases.

Conclusion

The survey provided a ‘snapshot’ of the situation for patients and families affected by Gaucher disease, helping the EGA direct its activities into areas of greatest need.

Gaucher disease

Gaucher disease is the commonest lysosomal storage disease seen in India and worldwide. It should be considered in any child or adult with an unexplained splenohepatomegaly and cytopenia which are seen in the three types of Gaucher disease. Type 1 is the non-neuronopathic form and type 2 and 3 are the neuronopathic forms. Type 2 is a more severe neuronopathic form leading to mortality by 2 years of age. Definitive diagnosis is made by a blood test-the glucocerebrosidase assay. There is no role for histological examination of the bone marrow, liver or spleen for diagnosis of the disease. Molecular studies for mutations are useful for confirming diagnosis, screening family members and prognosticating the disease. A splenectomy should not be performed except for palliation or when there is no response to enzyme replacement treatment or no possibility of getting any definitive treatment. Splenectomy may worsen skeletal and lung manifestations in Gaucher disease. Enzyme replacement therapy (ERT) has completely revolutionized the prognosis and is now the standard of care for patients with this disease. Best results are seen in type 1 disease with good resolution of splenohepatomegaly, cytopenia and bone symptoms. Neurological symptoms in type 3 disease need supportive care. ERT is of no benefit in type 2 disease. Monitoring of patients on ERT involves evaluation of growth, blood counts, liver and spleen size and biomarkers such as chitotriosidase which reflect the disease burden. Therapy with ERT is very expensive and though patients in India have so far got the drug through a charitable access programme, there is a need for the government to facilitate access to treatment for this potentially curable disease. Bone marrow transplantation is an inferior option but may be considered when access to expensive ERT is not possible.

Gaucher disease

Gaucher disease is an autosomal recessive condition due to glucocerebrosidase deficiency responsible for the lysosomal accumulation of glucosylceramide, a complex lipid derived from cell membranes, mainly in macrophages. It is due to mutations mostly in the GBA gene, although saposine C deficiency is due to mutations in the PSAP gene. It encompasses an extremely heterogeneous spectrum of clinical involvement from the fetus to adulthood. Splenomegaly, blood cytopenia, and bone involvement are the main manifestations of Gaucher disease, but nervous system degeneration is observed in about 5-10% of patients. The accumulation in neurons of glucosylceramide and its derivative, psychosine, are thought to underlie neuronal dysfunction and death, although Gaucher cells that mostly accumulate such substances are mainly macrophages. Enzyme replacement therapy dramatically improves the outcome of patients because of its extreme efficacy in the treatment of the systemic involvement. However, it has only limited effects on most neurological signs.

Evaluation of miglustat as maintenance therapy after enzyme therapy in adults with stable type 1 Gaucher disease: a prospective, open-label non-inferiority study

Background

Previous studies have provided equivocal data on the use of miglustat as maintenance therapy in Gaucher disease type 1. We report findings from a clinical trial evaluating the effects of miglustat treatment in patients with stable type 1 Gaucher disease after enzyme therapy.

Methods

Adult type 1 Gaucher disease patients stabilized during at least 3 years of previous enzyme therapy were included in this 2-year, prospective, open-label non-inferiority study. The primary endpoint was percent change from baseline in liver volume. Secondary endpoints included changes in spleen volume, hemoglobin concentration and platelet count.

Results

Forty-two patients were enrolled (mean±SD age, 45.1±12.7 years; previous enzyme therapy duration 9.5±4.0 years). Median (range) exposure to miglustat 100 mg t.i.d. was 658 (3–765) days. Twenty-one patients discontinued treatment prematurely; 13 due to adverse events, principally gastrointestinal. The upper 95% confidence limit of mean percent change in liver volume from baseline to end of treatment was below the non-inferiority margin of 10% (–1.1%; 95%CI −6.0, 3.9%). Mean (95%CI) changes in spleen volume, hemoglobin concentration and platelet count were 102 (24,180) mL, –0.95 (−1.38, –0.53) g/dL and −44.1 (–57.6, –30.7) ×10⁹/L, respectively.

Conclusions

The primary efficacy endpoint was met; overall there was no change in liver volume during 24 months of miglustat therapy. Several patients showed a gradual deterioration in some disease manifestations, suggesting that miglustat could maintain clinical stability, but not in all patients. Miglustat demonstrated a predictable profile of safety and tolerability that was consistent with that reported in previous clinical trials and experience in clinical practice.

Trial registration

Clinicaltrials.gov identifier NCT00319046

The cognitive profile of type 1 Gaucher disease patients

BACKGROUND

The absence of neurological symptoms and signs is traditionally considered mandatory for a diagnosis of type 1 Gaucher disease (GD1), but in recent years many reports have emerged on neurological manifestations in GD1 patients. Nevertheless, it has been unclear whether cognitive deficits are part of the disease as well.

METHODS

Cognitive function was assessed in a large cohort of GD1 patients with the use of the CDR system, a set of computerised cognitive tests. Testing was performed at baseline and every 6 months thereafter during a two-year study period.

RESULTS

Our patient cohort (84 patients, median age 40 years, median time from diagnosis 15 years) showed mild deficits relative to healthy age-matched subjects on the composite scores: power of attention (Z-score (mean ± SD) -0.9 ± 1.37) and speed of memory (Z-score (mean ± SD) -1.39 ± 1.49). No decline in cognitive function was seen during the two-year period. Age correlated with the composite scores variability of attention and quality of working memory. Moreover, severely affected patients (Zimran severity score (SSI) ≥ 15) scored more poorly compared to mildly affected patients (SSI ≤ 5) on the composite measure power of attention, reflecting the ability to concentrate.

CONCLUSIONS

GD1 patients exhibit mild deficits in power of attention and speed of memory, reflecting a decreased ability to focus attention and process information, together with a slowing in the speed of retrieval of items from memory. The clinical relevance of these findings is uncertain.