Paediatric non-neuronopathic Gaucher disease: recommendations for treatment and monitoring

Advancements in Viral Gene Therapy for Gaucher Disease

Gaucher disease, an autosomal recessively inherited lysosomal storage disorder, results from biallelic mutations in the GBA1 gene resulting in deficient activity of the enzyme glucocerebrosidase. In Gaucher disease, the reduced levels and activity of glucocerebrosidase lead to a disparity in the rates of formation and breakdown of glucocerebroside and glucosylsphingosine, resulting in the accumulation of these lipid substrates in the lysosome. This gives rise to the development of Gaucher cells, engorged macrophages with a characteristic wrinkled tissue paper appearance. There are both non-neuronopathic (type 1) and neuronopathic (types 2 and 3) forms of Gaucher disease, associated with varying degrees of severity. The visceral and hematologic manifestations of Gaucher disease respond well to both enzyme replacement therapy and substrate reduction therapy. However, these therapies do not improve the neuronopathic manifestations, as they cannot cross the blood-brain barrier. There is now an established precedent for treating lysosomal storage disorders with gene therapy strategies, as many have the potential to cross into the brain. The range of the gene therapies being employed is broad, but this review aimed to discuss the progress, advances, and challenges in developing viral gene therapy as a treatment for Gaucher disease.

Glucosylsphingosine (Lyso-Gb1): An Informative Biomarker in the Clinical Monitoring of Patients with Gaucher Disease

Historically, disease burden and treatment responses in patients with Gaucher disease (GD) was assessed by monitoring clinical data, laboratory, imaging, chitotriosidase (CHITO), and other biomarkers; however, these biomarkers lack specificity and CHITO is uninformative in patients heterozygous or homozygous for the CHIT1 c.1049_1072dup24 variant. Recently, glucosylsphingosine (lyso-Gb₁), a sensitive and specific GD biomarker, has been recommended for patient monitoring. Furthermore, studies measuring lyso-Gb₁ and CHITO in patients on long-term treatment with enzyme replacement therapy (ERT) and/or substrate reduction therapy (SRT) reported as group data show a reduction in both analytes, yet individualized patient data are generally unavailable. We describe seven patients on long-term treatment with longitudinal clinical data with monitoring based on current treatment guidelines. We present four patients who exhibit stable disease with normalized CHITO despite elevated lyso-Gb₁. We present one patient who transitioned from ERT to SRT due to lack of a clinical response with life-threatening thrombocytopenia who responded with marked improvement in platelets, and normalized levels of both CHITO and lyso-Gb₁. Finally, we present two ERT to SRT switch patients with stable disease on ERT who exhibited non-compliance on SRT, one with mirrored marked elevations of CHITO and lyso-Gb₁; and another with normal CHITO and platelets, but increasing lyso-Gb₁ levels and enlarged spleen. These clinical vignettes highlight the role of lyso-Gb₁ as a sensitive biomarker in management of patients with GD, and its further value when CHITO is normal and thus uninformative. We highlight the personalized medicine approach needed to optimize treatment outcomes and recommendations for these patients.

Gaucher disease - therapeutic aspects in Romania

Gaucher disease is a rare autosomal recessive disease caused by the beta-glicosidase activity deficiency, which will lead to substrate accumulation mainly in the liver, spleen or bone marrow. The main symptoms are liver and spleen enlargement, anemia and low platelet count, bone crisis and fatigue. Several treatment options are available, as enzyme replacement therapy, substrate reduction therapy, or chaperones treatment whose effect is still studied. There are 77 adult patients treated at this time in Romania, 54 with intravenous enzyme replacement ant 23 with oral substrate reduction therapy. No severe adverse effects have been reported by now. All patients had improved disease related symptoms after the receiving of the treatment.

Ophthalmic manifestations of Gaucher disease: the most common lysosomal storage disorder

Gaucher disease (GD) results from a deficiency of glucocerebrosidase activity and the subsequent accumulation of the enzyme's metabolites, principally glucosylsphingosine and glucosylceramide. There are three principal forms: Type I, which is the most common, is usually considered non-neuronopathic. Type II, III and IIIc manifest earlier and have neurological sequelae due to markedly reduced enzyme activity. Gaucher's can be associated with ophthalmological sequelae but these have not been systematically reviewed. We therefore performed a comprehensive literature review of all such ophthalmic abnormalities associated with the different types of Gaucher disease. We systematically searched the literature (1950 - present) for functional and structural ocular abnormalities arising in patients with Gaucher disease and found that all subtypes can be associated with ophthalmic abnormalities; these range from recently described intraocular lesions to disease involving the adnexae, peripheral nerves and brain. In summary, Gaucher can affect most parts of the eye. Rarely is it sight-threatening; some but not all manifestations are amenable to treatment, including with enzyme replacement and substrate reduction therapy. Retinal involvement is rare but patients with ocular manifestations should be monitored and treated early to reduce the risk of progression and further complications. As Gaucher disease is also associated with Parkinsons disease and may also confer an increased risk of malignancy (particularly haematological forms and melanoma), any ocular abnormalities should be fully investigated to exclude these potential underlying conditions.

The Importance of a Multidisciplinary Approach in the Management of a Patient with Type I Gaucher Disease

Managing the multisystemic symptoms of type I Gaucher Disease (GD) requires a multidisciplinary team approach that includes disease-specific treatments, as well as supportive care. This involves a range of medical specialists, general practitioners, supportive care providers, and patients. Phenotype classification and the setting of treatment goals are important for optimizing the management of type I GD, and for providing personalized care. The ability to classify disease severity using validated measurement tools allows the standardization of patient monitoring, and the measurement of disease progression and treatment response. Defining treatment goals is useful to provide a benchmark for assessing treatment response and managing the expectations of patients and their families. Although treatment goals will vary depending on disease severity, they include the stabilization, improvement or reversal (if possible) of clinical manifestations. Enzyme replacement therapy (ERT) is the standard care for patients with type I GD, but a novel substrate reduction therapy (SRT), Eliglustat, has demonstrated safety and efficacy in selected patients. To ensure that treatment goals are being achieved, regular and comprehensive follow up are necessary.

Health-related quality of life in children and adolescents living with Gaucher disease and their parents

Objective: The health-related quality of life (HRQoL), clinical status and perceived burden of disease in children and adolescents with Gaucher Disease (GD) were assessed.

Method: A Spanish multicenter collaboration study involving 13 hospitals was performed to evaluate pediatric patients with GD (n = 17, ages 5–18; n = 3, ages 2–4) and their parents (n = 20) using a HRQoL measure (PedsQL 4.0) and a survey on the perceived burden of the disease. Three children under five years old were evaluated by parent proxy-report. Relevant medical and socio-demographical characteristics were recorded.

Results: Sixty-nine percent of the participants with GD had mild and 31% had moderate severity level, all receiving enzyme replacement therapy (ERT). HRQoL was associated with the severity score index and was adjusted for age. Age was related to school functioning (older patients had lower scores), and female patients reported worse school functioning than males. Symptoms such as bone, joint or abdominal pain, bleeding, and fatigue were negatively associated with HRQoL. Perceptions of the burden related to GD, such as feeling ill and feeling sad, were negatively associated with HRQoL. Although the PedsQL scores of children and parents showed concordance, patterns of association between symptoms and perceived burden differed between children and parents. No associations were observed between HRQoL scores and time on ERT or ERT dosage.

Conclusion: HRQoL perceptions were affected by clinical status, observable and subjective symptoms, feelings of burden related to the disease, and patient characteristics (e.g. age and gender). Aspects of the disease that affect HRQoL may be perceived differently by children and parents.

Recent advances in the diagnosis and management of Gaucher disease

INTRODUCTION

Gaucher disease, the autosomal recessive deficiency of the lysosomal enzyme glucocerebrosidase, is associated with wide phenotypic diversity including non-neuronopathic, acute neuronopathic, and chronic neuronopathic forms. Overlap between types can render definitive diagnoses difficult. However, differentiating between the different phenotypes is essential due to the vast differences in clinical outcomes and response to therapy. Genotypic information is helpful, but cannot always be used to make clinical predictions. Current treatments for Gaucher disease, including enzyme replacement therapy and substrate reduction therapy, can reverse many of the non-neurological manifestations, but these therapies must be administered continually and are extremely costly.

AREAS COVERED

We reviewed the literature concerning the varied clinical presentations of Gaucher disease throughout the lifetime, along with treatment options, management goals, and current and future research challenges. A PubMed literature search was performed for relevant publications between 1991 to January 2018.

EXPERT COMMENTARY

Interest and research in the field of Gaucher disease is rapidly expanding. However, significant barriers remain in our ability to predict phenotype, assess disease progression using objective biomarkers, and determine optimal treatment strategy on an individual basis. As the field grows, we anticipate identification of genetic modifiers, new biomarkers, and small-molecule chaperone therapies, which may improve patient quality of life.

Early manifestations of type 1 Gaucher disease in presymptomatic children diagnosed after parental carrier screening

PURPOSE

The overall published experience with pediatric type 1 Gaucher disease (GD1) has been based on ascertainment through clinical presentation of the disease. We describe the longitudinal follow-up in a presymptomatic pediatric cohort.

METHODS

The cohort includes children diagnosed with GD1, either prenatally or postnatally by molecular genetic testing, and followed for clinical care at our center from 1998 to 2016. All patients' parents were GBA mutation carriers identified through carrier screening programs. Longitudinal clinical, laboratory, and imaging data were obtained through chart review.

RESULTS

Thirty-eight patients aged 1-18 years (mean at last visit 6.9 ± 4.1 years) were followed, including 32 p.N409S homozygotes and 6 p.N409S/p.R535H compound heterozygotes. At the last evaluation, a minority had hematological (5%), bone (15%), or linear growth (19%) issues. Only 12% had splenomegaly and 74% had moderate hepatomegaly. Chitotriosidase activity varied widely (6-5,640 nmol/hour/ml) and generally increased with age. Pediatric Gaucher severity scores (GSS) remained stable and within the mild-disease range for most (95%). Treatment for progressive disease during this period was recommended for four children.

CONCLUSION

Most children with the p.N409S/p.N409S and p.N409S/p.R535H GD1 genotypes have minimal disease manifestations and progression during childhood and can be monitored using limited assessments. Those with other mutations may require additional monitoring. These data are valuable for newborn screening and counseling.Genet Med advance online publication 13 October 2016.

Gaucher disease types 1 and 3: Phenotypic characterization of large populations from the ICGG Gaucher Registry

Study of the natural history of Gaucher disease has revealed marked phenotypic variation. Correlations to genotypes could provide insight into individual susceptibility to varying disease severity, which may impact whole-life medical care, reproductive decisions, and therapeutic choices for affected families. Importantly, pre-symptomatic or prospective interventions or the use of therapies with significant risk require accurate risk-benefit analyses based on the prognosis for individual patients. The body of international data held within the International Collaborative Gaucher Group (ICGG) Gaucher Registry provides an unprecedented opportunity to characterize the phenotypes of Gaucher disease types 1 and 3 and to appreciate demographic and ethnic factors that may influence phenotypes. The diversity of GBA gene mutations from patients with Gaucher disease represented in the ICGG Gaucher Registry database and in the literature provides the basis for initial genotype/phenotype correlations, the outcomes of which are summarized here.

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.

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.

Drug treatment of inborn errors of metabolism: a systematic review

BACKGROUND

The treatment of inborn errors of metabolism (IEM) has seen significant advances over the last decade. Many medicines have been developed and the survival rates of some patients with IEM have improved. Dosages of drugs used for the treatment of various IEM can be obtained from a range of sources but tend to vary among these sources. Moreover, the published dosages are not usually supported by the level of existing evidence, and they are commonly based on personal experience.

METHODS

A literature search was conducted to identify key material published in English in relation to the dosages of medicines used for specific IEM. Textbooks, peer reviewed articles, papers and other journal items were identified. The PubMed and Embase databases were searched for material published since 1947 and 1974, respectively. The medications found and their respective dosages were graded according to their level of evidence, using the grading system of the Oxford Centre for Evidence-Based Medicine.

RESULTS

83 medicines used in various IEM were identified. The dosages of 17 medications (21%) had grade 1 level of evidence, 61 (74%) had grade 4, two medications were in level 2 and 3 respectively, and three had grade 5.

CONCLUSIONS

To the best of our knowledge, this is the first review to address this matter and the authors hope that it will serve as a quickly accessible reference for medications used in this important clinical field.

Revised recommendations for the management of Gaucher disease in children

Gaucher disease is an inherited pan-ethnic disorder that commonly begins in childhood and is caused by deficient activity of the lysosomal enzyme glucocerebrosidase. Two major phenotypes are recognized: non-neuropathic (type 1) and neuropathic (types 2 and 3). Symptomatic children are severely affected and manifest growth retardation, delayed puberty, early-onset osteopenia, significant splenomegaly, hepatomegaly, thrombocytopenia, anemia, severe bone pain, acute bone crises, and fractures. Symptomatic children with types 1 or 3 should receive enzyme replacement therapy, which will prevent debilitating and often irreversible disease progression and allow those with non-neuropathic disease to lead normal healthy lives. Children should be monitored every 6 months (physical exam including growth, spleen and liver volume, neurologic exam, hematologic indices) and have one to two yearly skeletal assessments (bone density and imaging, preferably with magnetic resonance, of lumbar vertebrae and lower limbs), with specialized cardiovascular monitoring for some type 3 patients. Response to treatment will determine the frequency of monitoring and optimal dose of enzyme replacement. Treatment of children with type 2 (most severe) neuropathic Gaucher disease is supportive. Pre-symptomatic children, usually with type 1 Gaucher, increasingly are being detected because of affected siblings and screening in high-prevalence communities. In this group, annual examinations (including bone density) are recommended. However, monitoring of asymptomatic children with affected siblings should be guided by the age and severity of manifestations in the first affected sibling. Treatment is necessary only if signs and symptoms develop.

CONCLUSION

Early detection and treatment of symptomatic types 1 and 3 Gaucher disease with regular monitoring will optimize outcome. Pre-symptomatic children require regular monitoring. Genetic counseling is important.

Gaucher's Disease in Albanian Children: Casuistics and Treatment

OBJECTIVE

Gaucher's disease is a rare genetic disorder that results in the accumulation of cerebrosides in the liver, spleen, kidneys, lungs, brain and bone marrow. The deficiency of the specific lysosomal enzyme glucocerebrosidase is considered as causative factor. The first effective treatment for the disease, the drug Ceredase, approved in 1995, was replaced in 2001 by the drug Cerezyme®.

METHODS

During the period 2004-2009 in our service 11 children were hospitalized and treated for Gaucher's disease: 9 children with type 1, and 2 children with type 3 of the disease. The enzymatic examinations of the biomarker chitotriosidase were performed in Sahlgren's University Hospital, Mölndal Sweden; the DNA analysis was performed in the Children's Hospital & Regional Medical Center, Seattle, USA.

FINDINGS

We are presenting the biological and genetic molecular data of the children. In our case series, one year after the treatment started, the hemoglobin level was normalized; the platelet count was normalized in 7 patients after one year of treatment, and in 9 patients after two years of treatment. The hemorrhagic syndrome stopped after 6 months of treatment. Chitotriosidase values decreased 10-20 times the initial value, after one year of treatment and in one case the value reached the normal range. The treatment with Cerezyme® has also improved the visceral and biological signs. Anomalies of the oculomotricity were less sensitive to the treatment.

CONCLUSION

According to our experience, Chitotriosidase is a sensitive and specific marker in diagnosing and monitoring Gaucher's disease. The enzyme replacement therapy through Cerezyme® is an effective and safe treatment of Gaucher's disease. Blood signs (anemia, platelet count); visceral signs (splenomegaly, hepatomegaly) as well as bone involvement showed decisive improvement under the therapy.

Munchausen syndrome by proxy mimicking as Gaucher disease

Although rare, Munchausen syndrome by proxy (MBP) is a potentially life-threatening form of child abuse. Here, we report a 19-month-old female infant who presented with hepatosplenomegaly, anemia, thrombocytopenia, and recurrent septicemia. She was initially thought to have myelodysplastic syndrome. Further hematological and immunological investigations revealed no cause. beta-Glucosylceramidase enzyme activity on dried blood spot was suggestive of Gaucher disease. However, the enzyme level on cultured skin fibroblast was not consistent with Gaucher disease. The first hint about MBP was the recurrent sepsis with numerous gram negative rods. Furthermore, the mother's behavior and health history raised our suspicion about MBP. The child showed significant improvement after she was separated from the mother for a week. Finally, the mother confessed that she was spitting in local herbs and injecting it into the central line. This is, to our knowledge, the first report of MBP resembling in its presentation Gaucher disease. This case should alert the general and specialized pediatricians about MBP, as it may mimic metabolic diseases like Gaucher disease.

Optimal therapy in Gaucher disease

Gaucher disease (GD), the inherited deficiency of the lysosomal enzyme glucocerebrosidase, presents with a wide range of symptoms of varying severity, and primarily affects the skeletal, hematologic and nervous systems. To date, the standard of care has included enzyme replacement therapy with imiglucerase. Although imiglucerase is highly effective in reversing the visceral and hematologic manifestations, skeletal disease is slow to respond, pulmonary involvement is relatively resistant, and the CNS involvement is not impacted. Because of the recent manufacturing and processing problems, the research and development of alternative therapeutics has become more pressing. The divergent phenotypes and the heterogeneity involving different organ systems implicates the involvement of several pathological processes that include enzyme deficiency, substrate accumulation, protein misfolding, and macrophage activation, that differ in each patient with GD. Thus, the therapy should be tailored individually in order to target multiple pathways that interplay in GD.

A validated disease severity scoring system for adults with type 1 Gaucher disease

PURPOSE

A validated disease severity scoring system (DS3) for Gaucher disease type 1 (GD1) is needed to standardize patient monitoring and to define patient cohorts in clinical studies.

METHODS

DS3 domains were established by an expert physician group using the nominal group technique of consensus formation. Items were selected by 36 GD1 physicians. The expert group determined appropriate measurement techniques for each item. Measurements were weighted considering contributions to GD1 morbidity and mortality. Consensus Clinical Global Impression Severity scores for sample cases were compared with average DS3 scores. A minimal clinically important difference in GD1 DS3 score was calculated.

RESULTS

The GD1 DS3 includes bone (42% of score), hematologic (32%), and visceral domains (26%); individual items use routine assessments, including medical history, blood chemistry, organ volume measurements, and bone evaluations (magnetic resonance imaging and dual x-ray absorptiometry). The maximum score is 19. Interrater reliability was 0.97 (Cohen's kappa). DS3 scores were highly correlated with Clinical Global Impression Severity scores (r2 = 0.89). The minimal clinically important difference was -3.2 improvement and +3.9 deterioration.

CONCLUSION

This DS3 accurately quantifies GD1 status and intrapatient change over time. Testing of reliability and validity will continue to allow eventual implementation of the DS3 in clinical studies and routine practice.

Plasma Chitotriosidase Activity and Arteriogenic Erectile Dysfunction: Association with the Presence, Severity, and Duration

Introduction. Plasma chitotriosidase (ChT) activity is associated with the presence of atherosclerosis and is a new cardiovascular risk marker. Although available evidence supports its role in atherogenesis, there is a lack of an obvious correlation between plasma ChT activity and erectile dysfunction (ED). Aim. Our aim was to investigate the association of the level of serum ChT activity with ED. Main Outcome Measures. Erectile function was assessed using Sexual Health Inventory for Men (SHIM). Serum fasting lipid profile (plasma total cholesterol, low density lipoprotein cholesterol, high density lipoprotein cholesterol, and triglycerides); sex hormones (luteinizing hormone, follicle-stimulating hormone, prolactin, total testosterone, and estradiol); and thyroid-stimulating hormone were measured. Plasma ChT activity, as well as K(m), V(max), optimum pH, and heat stability of the ChT were also assessed. Penile duplex ultrasound examination before and after intracavernous injection of 20 microg prostaglandin E1 (PGE(1)), pudendal nerve conduction tests and sensory-evoked potential studies were done to identify patients with arteriogenic ED. Intima-media thickness (IMT) and plaque formation of common carotid artery were determined bilaterally using B-mode ultrasonography. Methods. A total of 124 normolipidemic patients with ED and 120 healthy controls were recruited for this study. Results. Serum ChT activity in patients with ED (116 +/- 18 nmol/h/mL) was significantly higher than in normal control subjects (51 +/- 12 nmol/h/mL) (P < 0.001). There was a significant positive correlation between plasma ChT activity and (i) severity of ED and (ii) duration of ED (r = 0.68, P = 0.004; and r = 0.62, P = 0.01 respectively).We also found that all ChT kinetic parameters assessed (K(m), V(max), and optimum pH) in plasma of ED patients were significantly different from those of normal controls (all P < 0.001). The results of heat stability analysis, demonstrated that plasma ChT activity in the normal individuals was more stable than in the patients with arteriogenic ED (P < 0.001). A significant correlation was seen between the plasma ChT activity and the mean common carotid IMT (r = 0.78, P = 0.002). Moreover, a significant correlation was seen between the severity of ED and mean common carotid IMT (r = 0.74, P = 0.003). We did not address chitotriosidase genotype. Conclusions. Our results indicate that plasma ChT activity is increased in normolipidemic patients with arteriogenic ED, suggesting its possible role in the pathophysiology of arteriogenic ED. The clinical significance of this increase should be assessed in further studies. Safarinejad MR, and Safarinejad SH. Plasma chitotriosidase activity and arteriogenic erectile dysfunction: Association with the presence, severity, and duration. J Sex Med **;**:**-**.

Review of the safety and efficacy of imiglucerase treatment of Gaucher disease

Most patients who suffer from symptomatic Gaucher disease will benefit from enzyme replacement therapy (ERT) with imiglucerase. The safety profile is excellent, only a small percentage of those exposed developing antibodies; similarly, very few patients require pre-medication for allergic reactions. Within 3 to 5 years of imiglucerase therapy, best documented at doses of 30 to 60 units/kg/infusion, hepatosplenomegaly can be expected to be reduced so that the liver volume will be maintained at 1 to 1.5 times normal (30% to 40% reduction from advent of ERT) and spleen volume to </= 2 to 8 times normal (50% to 60% reduction from advent of ERT). For anemic and thrombocytopenic patients, with 2 to 5 years of imiglucerase, hemoglobin levels are expected to be >/= 11 g/dL for women and children and >/= 12 g/dL for men; and platelet counts in patients with an intact spleen, depending on the baseline value, should approximately be doubled. Bone crises and bone pain but not irreversible skeletal damage will improve in most patients. Nonetheless, some features and some symptomatic patients apparently do not respond equally well and/or perhaps inadequately. The benefit for patients with the neuronopathic forms is primarily in improved visceral and hematological signs and symptoms. There are still several unresolved issues, the high per-unit cost being an important one, which have spurred the development of biosimilar enzymes as well as chaperone therapies currently in clinical trials.

Review of the safety and efficacy of imiglucerase treatment of Gaucher disease

Most patients who suffer from symptomatic Gaucher disease will benefit from enzyme replacement therapy (ERT) with imiglucerase. The safety profile is excellent, only a small percentage of those exposed developing antibodies; similarly, very few patients require pre-medication for allergic reactions. Within 3 to 5 years of imiglucerase therapy, best documented at doses of 30 to 60 units/kg/infusion, hepatosplenomegaly can be expected to be reduced so that the liver volume will be maintained at 1 to 1.5 times normal (30% to 40% reduction from advent of ERT) and spleen volume to </= 2 to 8 times normal (50% to 60% reduction from advent of ERT). For anemic and thrombocytopenic patients, with 2 to 5 years of imiglucerase, hemoglobin levels are expected to be >/= 11 g/dL for women and children and >/= 12 g/dL for men; and platelet counts in patients with an intact spleen, depending on the baseline value, should approximately be doubled. Bone crises and bone pain but not irreversible skeletal damage will improve in most patients. Nonetheless, some features and some symptomatic patients apparently do not respond equally well and/or perhaps inadequately. The benefit for patients with the neuronopathic forms is primarily in improved visceral and hematological signs and symptoms. There are still several unresolved issues, the high per-unit cost being an important one, which have spurred the development of biosimilar enzymes as well as chaperone therapies currently in clinical trials.

Enzyme replacement therapy in pediatric patients with Gaucher disease: what should we use as maintenance dosage?

INTRODUCTION

No consensus exists on the minimal dose of enzyme replacement therapy (ERT) effective to maintain therapeutic goals in pediatric Gaucher patients.

OBJECTIVE

Evaluate the efficacy of low dosage ERT to maintain treatment goals.

RESULTS

Six patients had a maintenance dose of 30-35U/kg/month. All patients, with the exception of one L444P/L444P homozygote, maintained therapeutic goals.

DISCUSSION

A low maintenance dose may be adequate in most pediatric patients. L444P homozygotes may require a higher maintenance dosage.

Goal-oriented therapy with miglustat in Gaucher disease

BACKGROUND

Gaucher disease (GD) is a highly heterogeneous disorder with multisystem involvement. Specific therapeutic goals for each manifestation of type 1 GD (GD1) were established in 2004 by an international panel of experts, to facilitate better management of GD1 patients. The goals were defined based on experience with enzyme replacement therapy (ERT) using imiglucerase. Miglustat, a small iminosugar, is the only commercially available substrate reduction therapy (SRT) for patients with GD1. Several clinical studies have demonstrated the beneficial effects of miglustat on cardinal disease manifestations of GD1.

OBJECTIVE

To review the currently available data on miglustat, and provide guidance on the attainment of the GD therapeutic goals with miglustat therapy.

METHODS

A literature search identified publications on miglustat using MEDLINE, HighWire Press, and Google Scholar databases. Articles were identified using the terms 'miglustat' and 'Gaucher disease type 1'.

FINDINGS

Improvements in hematological manifestations and organomegaly can be expected with miglustat therapy, with disease stabilization achievable over the long term. Recent data suggest that miglustat can maintain stability in patients with mild to moderate GD1 who have been previously treated with ERT. Miglustat may be beneficial with regards to bone manifestations, with reduction in the incidence of patients reporting bone pain and improvements in bone mineral density seen within the first 24 months of therapy.

CONCLUSIONS

Several of the therapeutic goals for patients with GD1 can be achieved with miglustat therapy. In select cases, miglustat can be considered an alternative to ERT for the treatment of patients with GD1. Long-term experience with the use of miglustat will help define its overall safety and efficacy; this information will be useful in determining the role of SRT using miglustat in the management of the general adult GD1 patient population.

Gaucher disease: The importance of early diagnosis and therapy

A Gaucher-kór a leggyakoribb lizoszomális tárolási betegség, amelyet a glukocerebrozidáz nevű lizoszomális enzim elégtelen működése okoz. A nemzetközi Gaucher-regiszterben 2006 végén 4584 beteget tartottak nyilván, közülük 34 volt magyar. A betegségnek három típusa van: nem neuropathiás (1. típus), akut neuropathiás (2. típus) és krónikus neuropathiás (3. típus). Ezek közül a nem neuropathiás típus a leggyakoribb, amelynek klinikai megjelenési formái nagy változatosságot mutatnak, és a tünetek a betegek több mint felében tízéves kor előtt jelentkeznek. A gyermekkori manifesztáció rendszerint súlyosabb fenotípusra utal, az irreverzíbilis komplikációk kialakulásának a veszélye nagy. A biztonságos és hatékony enzimszubsztitúciós kezelést 1991 óta alkalmazzák, Magyarországon 1992 óta elérhető. Az optimális dózisban történő korai kezelés megállítja a betegség progresszióját, a korábban kialakult visceralis és hematológiai eltérésekben regressziót idéz elő, megelőzi az irreverzíbilis csontelváltozások kialakulását, és biztosítja a betegek jó életminőségét. A szerzők három, korai gyermekkorban diagnosztizált Gaucher-kóros betegük kórtörténetét mutatják be. Felhívják a figyelmet a korai diagnózis és az irreverzíbilis komplikációk kialakulása előtt elkezdett kezelés fontosságára. A kórkép időben történő felismerése nagy kihívást jelent a gyermekgyógyászok számára.

Clinical consequences of interrupting enzyme replacement therapy in children with type 1 Gaucher disease

OBJECTIVE

To document the effects of interrupting enzyme replacement therapy (ERT) for at least 1 year in a group of children with type 1 Gaucher disease.

STUDY DESIGN

All children with type 1 Gaucher disease who were treated at 2 pediatric centers and who were required to suspend ERT for at least 1 year were studied before, during, and after treatment interruption. Hemoglobin and platelet levels, organomegaly, growth, and bone manifestations were monitored.

RESULTS

Five of 32 children experienced treatment interruptions. Before ERT, all children had splenomegaly, 4 children had hepatomegaly, 4 children had growth retardation, 3 children had skeletal manifestations, 3 children had thrombocytopenia, and 1 child had anemia. After 1 to 7 years of ERT, all children were growing normally, none had skeletal manifestations, organomegaly had decreased or disappeared, and hematologic features had improved. After 15 to 36 months of ERT interruption, splenomegaly recurred or worsened in all children, hepatomegaly and hematologic features recurred or worsened in 4 children, serious bone manifestations developed in 4 children, and 3 children experienced growth retardation. After at least 11 months of resumed ERT in 4 children, 2 had hepatomegaly, 2 had splenomegaly, and all had persistent skeletal manifestations.

CONCLUSION

Interruption of ERT in children with type 1 Gaucher disease should be avoided because it can cause recurrent organomegaly, growth delays, and skeletal manifestations that do not resolve after treatment reinstatement.

Use of plain radiography to optimize skeletal outcomes in children with type 1 Gaucher disease in Brazil

BACKGROUND

Gaucher disease is the most common lysosomal storage disease and is caused by deficient production and activity of the lysosomal enzyme beta-glucosidase (glucocerebrosidase), resulting in progressive accumulation of glucosylceramide (glucocerebroside) in lysosomes of cells of the reticuloendothelial system in the spleen, liver, and marrow. Clinical manifestations include anemia, thrombocytopenia, hepatosplenomegaly, and bone complications, including bone pain, bone marrow infiltration, lytic lesions, osteopenia, pathological fractures, and avascular necrosis. Early, adequate, and sustained treatment with enzyme replacement therapy (ERT) available since 1991 can change the natural history of the disease, particularly in children. Skeletal complications are usually the major source of disease morbidity and disability and although magnetic resonance imaging and dual-energy x-ray absorptiometry densitometry are recommended for monitoring, these are not readily available in all countries.

METHODS

We describe 18 Brazilian children with type 1 Gaucher disease with bone involvement who were followed with plain radiography for at least 8 months after beginning imiglucerase ERT (initial dose, 15-60 U/kg body weight/15 days). Bone involvement noted by plain radiograph included marrow infiltration, osteopenia, pathological fractures, osteonecrosis, lytic lesions, and Erlenmeyer flask deformity. Patients were questioned about bone crises.

RESULTS

Patients were followed for up to 10 years (mean follow-up, 4 years and 4 months +/- 3 years and 3 months). Bone changes were visible by plain radiographs in all patients. Clinical and radiological improvement was noted in 13 (72%) of 18 patients; bone lesions worsened in 5 (28%) of 18 patients. The final ERT dose for the 13 patients who improved was 55 +/- 10 U/kg (range, 30-60 U/kg), and the final ERT dose for the 5 who worsened was 29 +/- 2 U/kg (range, 26-30 U/kg); this difference was statistically significant (P < 0.03).

CONCLUSIONS

When other imaging technologies are not available, skeletal response to ERT in children with type 1 Gaucher disease can be monitored effectively by plain radiography. Higher doses of ERT (50-60 U/kg /15 days) may be required for improvement of skeletal manifestations.

CLINICAL EVIDENCE

Case series; level 4.

Ultrastructural features of gaucher disease treated with enzyme replacement therapy presenting as mesenteric mass lesions

The classical ultrastructural features of Gaucher disease include large numbers of intracytoplasmic, membrane-bound lysosomal inclusions containing characteristic tubular structures on an electron-lucent background, representing the periodic acid schiff (PAS)-positive Gaucher cells identifiable on light microscopy. Following enzyme replacement therapy (ERT), many of the manifestations of the condition are ameliorated, but persistent mesenteric lymphadenopathy has been reported, the ultrastructural features of which previously have not been described. Two children, aged 4 and 8 years old, respectively, both presented with persistent abdominal lymphadenopathy whilst receiving ERT for Gaucher disease. Needle core biopsies were carried out, that demonstrated collections of macrophages and only scattered storage-type cells on light microscopy. PAS staining was negative in one case and only focally positive in the other Electron microscopic examination, however, confirmed the cells represented macrophages, the cytoplasm of which contained scattered abnormal inclusions containing occasional twisted tubular structures of the type reported in classic Gaucher disease. ERT in Gaucher disease appears to reduce accumulation of the metabolic products at many sites. But for uncertain reasons, abdominal lymphadenopathy may occur containing macrophages that do not form granulomas or classic Gaucher cells on light microscopy. These probably represent incomplete clearance, incomplete/partial enzyme replacement, or possibly an unusual response to a relatively small amount of storage material.

CCL18: a urinary marker of Gaucher cell burden in Gaucher patients

Glucosylceramide-laden tissue macrophages in Gaucher patients secrete large quantities of chitotriosidase and CC chemokine ligand 18 (CCL18), resulting in markedly increased plasma levels. We have comparatively investigated the occurrence of both parameters in plasma and urine samples of Gaucher patients. Chitotriosidase was high in urine samples of some symptomatic patients, but elevations did not correlate with increased plasma concentrations. Urinary chitotriosidase was particularly high in a patient with severe kidney involvement and local storage cell infiltration. Urinary levels of CCL18 were also highly elevated in samples from Gaucher patients as compared to controls. The median value of the CCL18/creatinine ratio in urine samples of 31 Gaucher patients was 143.3 pg/micromol (range 32-551) and in those of 12 normal subjects was 4.1 pg/micromol (range 1.3-6.8). In sharp contrast to chitotriosidase, increases in the low-molecular-mass chemokine CCL18 in urine and plasma specimens of Gaucher patients correlated well. A correlation was also observed for reductions in urinary and plasma CCL18 following therapy. It is concluded that assessment of urinary CCL18 of Gaucher patients gives insight into the total body burden on Gaucher cells, whereas that of chitotriosidase does not. Urinary chitotriosidase appears rather to be a reflection of renal pathology.

Lysosomal storage diseases: natural history and ethical and economic aspects

Potential treatment for lysosomal diseases now includes enzyme replacement therapy, substrate reduction therapy, and chaperone therapy. The first two of these have been implemented commercially, and the spectrum of diseases that are now treatable has expanded from Gaucher disease to include several other disorders. Treatment of these diseases is extremely costly. We explore some of the reasons for the high cost and discuss how, by proper selection of patients and appropriate dosing, the economic burden on society of treating these disease may be ameliorated, at least in part. However, the cost of treating rare diseases is a growing problem that society needs to address.

Evidence-based recommendations for monitoring bone disease and the response to enzyme replacement therapy in Gaucher patients

BACKGROUND

Bone disease is a serious complication of Gaucher disease. Untreated, it can result in pain, permanent bone damage and disability. Enzyme replacement therapy reverses many of the clinical signs of Gaucher bone disease but early assessment and treatment, and regular monitoring, are essential in optimising outcomes.

SCOPE

In September 2005, a group of European experts met to review current knowledge and identify best practice and unmet needs in the monitoring of Gaucher bone disease and the response to enzyme replacement therapy.

METHODS

Medline searches of peer-reviewed literature (no date restrictions) were conducted and supplemented by additional information considered relevant by panellists to furthering discussions.

FINDINGS AND CONCLUSIONS

The group's recommendations included: currently used biochemical bone markers are not clinically practical or reliable; plain X-rays should not be the sole method of assessing bone disease; MRI is the most sensitive method for monitoring bone marrow infiltration by Gaucher cells; semi-quantitative methods for assessing bone marrow infiltration in routine clinical practice should use readily available technology, include an assessment of Gaucher cell infiltration in the lumbar spine and femur, and be validated for inter-rater reliability and in comparison to other methods; a multidisciplinary approach is required for the treatment of Gaucher patients; all Gaucher patients should receive a comprehensive initial radiologic evaluation for bone disease and ongoing radiological monitoring at least once every 2 years.

Recent clinical progress in Gaucher disease

PURPOSE OF REVIEW

Major clinical advances in Gaucher disease focus on detection, prediction and treatment of variant phenotypes.

RECENT FINDINGS

The advent of efficacious enzyme therapy has emphasized the importance of early diagnosis and intervention to prevent the morbid manifestations of the disease including organomegaly, growth and pubertal retardation, and osteopenia/osteoporosis. Genotype/phenotype correlations provide some guidance for prognosis by categorical distinctions of nonneuronopathic (type 1) and neuronopathic (types 2 and 3) variants. Early detection of children genetically predisposed to severe disease are a management challenge for the pediatrician and metabolic physician. The development of specific therapeutic goals provides a framework for assessments of visceral therapeutic and palliative responses in children with type 1, and types 2 and 3, respectively.

SUMMARY

The pediatrician plays a major role in these clinical and genetically based decisions.

Gaucher disease type 1: Revised recommendations on evaluations and monitoring for adult patients

For patients with type 1 Gaucher disease, challenges to patient care posed by clinical heterogeneity, variable progression rates, and potential permanent disability that can result from untreated or suboptimally treated hematologic, skeletal, and visceral organ involvement dictate a need for comprehensive, serial monitoring. An updated consensus on minimum recommendations for effective monitoring of all adult patients with type 1 Gaucher disease has been developed by the International Collaborative Gaucher Group (ICGG) Registry coordinators. These recommendations provide a schedule for comprehensive and reproducible evaluation and monitoring of all clinically relevant aspects of this disease. The initial assessment should include confirmation of deficiency of beta-glucocerebrosidase, genotyping, and a complete family medical history. Other assessments to be performed initially and at regular intervals include a complete physical examination, patient-reported quality of life using the SF-36 survey, and assessment of hematologic (hemoglobin and platelet count), visceral, and skeletal involvement, and biomarkers. Specific radiologic imaging techniques are recommended for evaluating visceral and skeletal pathology. All patients should undergo comprehensive regular assessment, the frequency of which depends on treatment status and whether therapeutic goals have been achieved. Additionally, reassessment should be performed whenever enzyme therapy dose is altered, or in case of significant clinical complication.

Pediatric non-neuronopathic Gaucher disease: presentation, diagnosis and assessment. Consensus statements

Gaucher disease is caused by defective activity of glucocerebrosidase. The resulting accumulation of glucocerebroside in the lysosomes of visceral macrophages in various tissue and organ compartments leads to multiple manifestations, including hepatosplenomegaly, anemia, thrombocytopenia, growth retardation and skeletal disease. The most prevalent form of Gaucher disease is the non-neuronopathic (type 1) variant, which lacks primary involvement of the central nervous system. Traditionally, this has been referred to as the 'adult type'; however, 66% of individuals with symptomatic non-neuronopathic Gaucher disease manifest in childhood. Onset in childhood is usually predictive of a severe, rapidly progressive phenotype and children with non-neuronopathic Gaucher disease are at high risk for morbid complications. Enzyme therapy with recombinant human glucocerebrosidase in childhood can restore health in reversible manifestations and prevent the development of irreversible symptoms. A heightened focus on pediatric Gaucher disease is therefore needed. Although some correlation has been found between genotype and phenotype, mutation analysis is of limited value in disease prognosis. Management of pediatric Gaucher disease should be underpinned by a thorough assessment of the phenotype at baseline with regular monitoring thereafter. Excluding neuronopathic disease is recommended as the first step. Subsequently, baseline evaluation should focus on staging of different storage tissues, particularly the bone the involvement of which results in the greatest long-term morbidity. These organ assessments are recommended because bone disease severity may not correlate with disease severity in other organs and vice versa. In addition, different organs may respond differently to therapy. Initial assessment of each organ system can enable setting of realistic and individualized goals.

CONCLUSION

A thorough approach to baseline assessment will improve the understanding of childhood Gaucher disease, optimizing management to minimize impairment of growth and development and prevent irreversible symptoms.