A model of neuronopathic Gaucher disease

Histologic and ultrastructural study of intracranial Gaucheroma causing deafness in a patient with Gaucher disease type 3: Effects of substrate reduction therapy

Hearing loss is frequently associated with Gaucher disease (GD). Gaucher cells are enlarged reticuloendothelial cells containing glucocerebroside in the lysosomes due to deficiency of the glucocerebrosidase. Gaucheromas consist of accumulated Gaucher cells. Gaucher cells accumulate in variable tissues including the liver, spleen, bone marrow, and the middle ear and the mastoid causing conductive hearing loss. Neurons and astrocytes in the central nervous system are affected in neuronopathic GD leading to sensorineural hearing loss. Gaucheromas can develop even in patients treated with enzyme replacement therapy (ERT). We report a 19-year-old female patient with GD type 3 who developed profound bilateral hearing loss associated with intracranial Gaucheroma. Combination therapy of ERT with imiglucerase and substrate reduction therapy (SRT) with eliglustat significantly decreased the size of Gaucher cells and cleared the characteristic microtubular structures in the lysosomes in Gaucher cells. Early implementation of SRT may prevent at least conductive hearing impairment in GD although it may not prevent sensorineural hearing loss due to inner hair cell dysfunction which is also known to be associated with neuronopathic GD.

Clinical Outcomes of Patients with Chronic Neuropathic Form of Gaucher Disease in the Spanish Real-World Setting: A Retrospective Study

This was a retrospective, multicenter study that aimed to report the characteristics of type 3 Gaucher disease (GD3) patients in Spain, including the genotype, phenotype, therapeutic options, and treatment responses. A total of 19 patients with GD3 from 10 Spanish hospitals were enrolled in the study (14 men, 5 women). The median age at disease onset and diagnosis was 1 and 1.2 years, respectively, and the mean age at follow-up completion was 12.37 years (range: 1-25 years). Most patients exhibited splenomegaly (18/19) and hepatomegaly (17/19) at the time of diagnosis. The most frequent neurological abnormalities at onset were psychomotor retardation (14/19) and extrinsic muscle disorders (11/19), including oculomotor apraxia, supranuclear palsy, and strabismus. The L444P (c.1448T>C) allele was predominant, with the L444P (c.1448T>C) homozygous genotype mainly associated with visceral manifestations like hepatosplenomegaly, anemia, and thrombocytopenia. All patients received enzyme replacement therapy (ERT); other treatments included miglustat and the chaperone (ambroxol). Visceral manifestations, including hepatosplenomegaly and hematological and bone manifestations, were mostly controlled with ERT, except for kyphosis. The data from this study may help to increase the evidence base on this rare disease and contribute to improving the clinical management of GD3 patients.

Targeted Enzymatic VLP-Nanoreactors with β-Glucocerebrosidase Activity as Potential Enzyme Replacement Therapy for Gaucher's Disease

Gaucher disease is a genetic disorder and the most common lysosomal disease caused by the deficiency of enzyme β-glucocerebrosidase (GCase). Although enzyme replacement therapy (ERT) is successfully applied using mannose-exposed conjugated glucocerebrosidase, the lower stability of the enzyme in blood demands periodic intravenous administration that adds to the high cost of treatment. In this work, the enzyme β-glucocerebrosidase was encapsulated inside virus-like nanoparticles (VLPs) from brome mosaic virus (BMV), and their surface was functionalized with mannose groups for targeting to macrophages. The VLP nanoreactors showed significant GCase catalytic activity. Moreover, the Michaelis-Menten constants for the free GCase enzyme (KM =0.29 mM) and the functionalized nanoreactors (KM =0.32 mM) were similar even after chemical modification. Importantly, the stability of enzymes under physiological conditions (pH 7.4, 37 °C) was enhanced by ≈11-fold after encapsulation; this is beneficial for obtaining a higher blood circulation half-life, which may decrease the cost of therapy by reducing the requirement of multiple intravenous injections. Finally, the mannose receptor targeted enzymatic nanoreactors showed enhanced internalization into macrophage cells. Thus, the catalytic activity and cell targeting suggest the potential of these nanoreactors in ERT of Gaucher's disease.

A rare cause of hydrops fetalis in two Gaucher disease type 2 patients with a novel mutation

Gaucher disease type 2 is the most progressive and the rarest form of Gaucher disease, defined as the acute neuronopathic type. We presented two GD2 patients who died before three months of age due to severe septicemia, respiratory and liver failure. One was homozygous for a novel GBA variant c.590 T > A (p.197 K), and the second homozygous for the known GBA mutation c.1505G > A (p.R502H). Ichthyosis, hydrops fetalis, apnea, myoclonic seizures, and hepatosplenomegaly occurred in both patients, but hypertrophic cardiomyopathy was observed only in the second and unilateral cataract in the first patient. Due to the disease's early and rapid neurological progression, we did not administer ERT to our patients. It is strongly believed that early diagnosis is essential, and prenatal diagnosis makes genetic counselling possible for future pregnancies.

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.

Auditory brainstem response

The auditory brainstem response (ABR), consisting of five to six vertex-positive peaks with separation of about 0.8ms, is very sensitive to factors that affect conduction velocity and hence ABR wave latencies in the brainstem auditory pathways. In addition, disorders causing dissynchronization of neural activity result in an amplitude decrease or disappearance of ABR peaks. The opposite effects occur in the maturation process, which takes about 2 years postterm; here conduction velocity increases quickly to its adult value, but synaptic delays being sensitive to synchronous release of transmitter substance take considerably longer. In neurological disorders, those that cause dissynchrony, such as auditory neuropathy and vestibular schwannoma, Gaucher disease, and Krabbe disease, the (longer latency) ABR peaks are reduced or absent. Effects on neural conduction, resulting in increased ABR interwave latencies, are found in vestibular schwannomas, Bell's palsy, Duane retraction syndrome, Marcus Gunn ptosis, and various encephalomyopathies. These measures allow an assessment of the parts of the brainstem that are involved.

Middle-ear involvement in type I Gaucher's disease - a unique case

OBJECTIVE

Gaucher's disease is a rare autosomal recessive lysosomal storage disease. We describe a unique case of middle-ear involvement presenting with hearing loss.

CASE REPORT

A five-year-old boy with known Gaucher's disease presented with bilateral hearing impairment and conductive hearing loss on pure tone audiometry with flat tympanometry traces.

INTERVENTION

Exploratory Tympanomastoidectomy revealed inflammatory material filling the mastoid and the middle ear. Histological analysis confirmed Gaucher cell infiltrates.

CONCLUSION

This is the first detailed report in the english language literature of Gaucher's disease affecting the middle ear and the mastoid. We discuss the disease process and suggest future management options.

[Clinical characteristics of the neurological forms of Gaucher's disease]

Gaucher's disease is the most prevalent disease of accumulation of glycosphingolipids. Neurological involvement is used to classify the different types of the disease. Type 1 affects approximately 90% of patients, and visceral manifestations and bone marrow, without affecting the nervous system. Type 2 is considered a severe form of disease with severe nervous system and death within two years. Type 3 is late, slowly progressive neurological symptoms and survival until the third decade. Besides these classical syndromes, the best knowledge of the disease related to the existence of national registries, the increased survival of patients resulting from replacement therapy, and demonstration of the behavior of glucocerebrosidase mutations as a risk factor of neurodegenerative diseases, has expanded the clinical phenotype and altered the traditional classification of the disease.

Hearing in adults with Pompe disease

Hearing loss has been recognized as an important cause of morbidity in infants with Pompe disease, a metabolic disorder caused by deficiency of acid α-glucosidase. It is unknown whether hearing is also affected in adult Pompe patients. We have studied the prevalence, severity, and type of hearing loss in 58 adult patients using tympanometry and pure-tone audiometry. Compared to normative data (International Organisation for Standardisation standard 7029), 72% of patients had impaired hearing thresholds at one or more frequencies in at least one ear. All measured frequencies were equally affected. All patients had a sensorineural type of hearing loss, pointing to cochlear or retrocochlear pathology. Categorised according to the standards of the World Health Organisation 21% of patients had a clinically relevant hearing loss (16% slight, 3% moderate, 2% profound). Though this suggests that hearing loss occurs in a considerable number of patients with Pompe disease, this prevalence is similar to that in the general population. Therefore, we conclude that hearing loss is not a specific feature of Pompe disease in adults.

Type 2 Gaucher disease: phenotypic variation and genotypic heterogeneity

Gaucher disease (GD), the most common lysosomal storage disease, results from a deficiency of the lysosomal enzyme glucocerebrosidase. GD has been classified into 3 types, of which type 2 (the acute neuronopathic form) is the most severe, presenting pre- or perinatally, or in the first few months of life. Traditionally, type 2 GD was considered to have the most uniform clinical phenotype when compared to other GD subtypes. However, case studies over time have demonstrated that type 2 GD, like types 1 and 3, manifests with a spectrum of phenotypes. This review includes case reports that illustrate the broad range of clinical presentations encountered in type 2 GD, as well as a discussion of associated manifestations, pathological findings, diagnostic techniques, and a review of current therapies. While type 2 GD is generally associated with severe mutations in the glucocerebrosidase gene, there is also significant genotypic heterogeneity.

Calcium signaling via two-pore channels: local or global, that is the question

Recently, we identified, for the first time, two-pore channels (TPCs, TPCN for gene name) as a novel family of nicotinic acid adenine dinucleotide phosphate (NAADP)-gated, endolysosome-targeted calcium release channels. Significantly, three subtypes of TPCs have been characterized, TPC1-3, with each being targeted to discrete acidic calcium stores, namely lysosomes (TPC2) and endosomes (TPC1 and TPC3). That TPCs act as NAADP-gated calcium release channels is clear, given that NAADP binds to high- and low-affinity sites associated with TPC2 and thereby induces calcium release and homologous desensitization, as observed in the case of endogenous NAADP receptors. Moreover, NAADP-evoked calcium signals via TPC2 are ablated by short hairpin RNA knockdown of TPC2 and by depletion of acidic calcium stores with bafilomycin. Importantly, however, NAADP-evoked calcium signals were biphasic in nature, with an initial phase of calcium release from lysosomes via TPC2, being subsequently amplified by calcium-induced calcium release (CICR) from the endoplasmic reticulum (ER). In marked contrast, calcium release via endosome-targeted TPC1 induced only spatially restricted calcium signals that were not amplified by CICR from the ER. These findings provide new insights into the mechanisms that cells may utilize to "filter" calcium signals via junctional complexes to determine whether a given signal remains local or is converted into a propagating global signal. Essentially, endosomes and lysosomes represent vesicular calcium stores, quite unlike the ER network, and TPCs do not themselves support CICR or, therefore, propagating regenerative calcium waves. Thus "quantal" vesicular calcium release via TPCs must subsequently recruit inositol 1,4,5-trisphoshpate receptors and/or ryanodine receptors on the ER by CICR to evoke a propagating calcium wave. This may call for a revision of current views on the mechanisms of intracellular calcium signaling. The purpose of this review is, therefore, to provide an appropriate framework for future studies in this area.

Auditory neuropathy: clinical characteristics and therapeutic approach

PURPOSE

Auditory neuropathy is characterized by congenital sensorineural hearing loss associated with absent or impaired auditory brainstem evoked responses and preservation of outer hair cell activity. This study describes the recent experience of our tertiary pediatric center with auditory neuropathy (AN).

METHODS

The files of all children diagnosed with AN at our center from 2000 to 2005 were reviewed for background data, associated factors, laboratory and audiometry findings, management, and outcome.

RESULTS

Mean age at diagnosis was 13 months. Factors known to be associated with AN were found in 18 children, namely, prematurity, hyperbilirubinemia, parental consanguinity, or positive family history. Conception by in vitro fertilization was an additional factor not previously reported. The hearing loss was mostly moderate to severe, and bilateral in all patients but one. Otoacoustic emissions and/or cochlear microphonics were demonstrated in all cases. Hearing improved spontaneously in 4 patients. Management with a hearing aid was successful in 1 of 19 patients. Twelve patients received cochlear implants with good outcome.

CONCLUSION

Because neonates with AN have normal otoacoustic emissions and/or cochlear microphonics, screening tests for high-risk neonates should be complemented by auditory brainstem evoked responses to avoid false-negative findings. Because AN is considered a retrocochlear lesion, with normal outer hair cell function, rehabilitation with hearing aids is problematic. Although the level of pathology is apparently at the cochlear nerve, cochlear implantation is often a good solution for failures of conventional rehabilitation. However, our finding of spontaneous improvement in a small subgroup raises questions regarding implantation before age 1 year.

Diagnostik und Therapie der auditorischen Synaptopathie/Neuropathie

Pathological auditory brainstem responses (lack of responses, elevated thresholds and perturbed waveforms) in combination with present otoacoustic emissions are typical audiometric findings in patients with a hearing impairment that particularly affects speech comprehension or complete deafness. This heterogenous group of disorders first described as "auditory neuropathy" includes dysfunction of peripheral synaptic coding of sound by inner hair cells (synaptopathy) and/or of the generation and propagation of action potentials in the auditory nerve (neuropathy). This joint statement provides prevailing background information as well as recommendations on diagnosis and treatment. The statement focuses on the handling in the german language area but also refers to current international statements.

An open-label, noncomparative study of miglustat in type I Gaucher disease: efficacy and tolerability over 24 months of treatment

BACKGROUND

The substrate synthesis inhibitor miglustat (N-butyldeoxynojirimycin) is the first oral agent to receive regulatory approval for the treatment of type I Gaucher disease (GD).

OBJECTIVES

The aims of this study were to further assess previous observations of the effects of miglustat in adult patients with mild to moderate type I GD and to evaluate the tolerability and safety profile of this drug.

METHODS

This was a noncomparative, open-label study in adult patients with type I GD (confirmed by genotyping and glucocerebrosidase assay) who were unwilling or unable to receive enzyme replacement therapy (ERT) or who had discontinued ERT for at least 3 months. Patients received miglustat 100 mg TID for 12 months, with the option of continuing treatment for a further 12 months. The primary end point was the percentage change in liver volume. Secondary end points included the percentage change in spleen volume and changes in hematologic parameters (hemoglobin, platelets), chitotriosidase activity (a surrogate marker of disease burden), and bone assessments (dual-energy X-ray absorptiometry, magnetic resonance imaging, and radiography). Clinical safety was monitored, including assessment of neurologic status at baseline and throughout the study using a comprehensive battery of standardized neurologic tests (eg, Purdue Pegboard Test, Mini-Mental State Examination, nerve conduction studies) and neuropsychological tests.

RESULTS

Of the 10 patients (7 men, 3 women) who received at least 1 dose of miglustat, 7 completed 24 months of treatment. Patients were aged between 32 and 62 years (mean, 46.3 years) and weighed between 55 and 88 kg (mean, 72.4 kg). All patients had at least 1 manifestation of GD, including 10 with splenomegaly (mean size, 8.1 times normal; range, 3.9-15.9 times normal), 9 with thrombocytopenia, and 8 with hepatomegaly (mean size, 1.5 times normal; range, 1.0-2.0 times normal). At baseline, hemoglobin concentrations ranged from 11.5 to 15.1 g/dL (mean, 13.2 g/dL), platelet counts from 55 to 161 x 10(9)/L (mean, 83.8 x 10(9)/L), and chitotriosidase activity from 526 to 29636 nmol/mL . h (mean, 8143.7 nmol/mL . h). In the 8 patients comprising the efficacy set, significant mean percentage changes from baseline in liver volume were seen at 6 months (-8.4%; P = 0.036; 95% CI, -16.1 to -0.7) and 18 months (-15.1%; P = 0.022; 95% CI, -27.1 to -3.0). Although not statistically significant, the 95% CIs for the percentage changes in liver volume at 12 months (-9.4%; 95% CI, -19.5 to 0.6) and 24 months (-5.6%; 95% CI, -12.1 to 1.0) were similar to those at 6 and 18 months, supporting a consistent clinical effect. Significant mean percentage reductions in spleen volume were observed at 6 months (-19.0%; P = 0.006; 95% CI, -30.4 to -7.6) and 18 months (-24.3%; P = 0.001; 95% CI, -33.6 to -15.1). Mean hemoglobin concentrations, which were normal at baseline, remained stable over the course of the study. There were no significant changes in bone status. There was a significant mean increase in absolute platelet count at 12 months (by 13.9 x 10(9)/L; P = 0.030; 95% CI, 1.8 to 26.0); at 24 months, the mean percentage increase from baseline (23.0%) was not statistically significant. The mean percentage reduction from baseline in chitotriosidase activity at 24 months was 25.3%. Treatment was well tolerated, and the incidence of most adverse events decreased with time. Gastrointestinal and central nervous system adverse events reported during 3-month periods at the beginning (0-3 months) and end (>21-24 months) of the study were flatulence (10 and 2 patients, respectively), diarrhea (9 and 0), abdominal pain (7 and 1), tremor (4 and 1), paresthesia (3 and 0), headache (2 and 3), and abdominal distention (2 and 0). No evidence of clinically significant adverse effects on neurologic or neuropsychological function was found during the study.

CONCLUSIONS

In this small study in symptomatic adult patients with type I GD, miglustat treatment resulted in a significant decrease in liver and spleen volume at 6 and 18 months, with clinical improvement noted over 24 months. Bone involvement and platelet and hemoglobin values remained stable, with no significant changes noted during the observation period. The effects of treatment were consistent with those of earlier studies of miglustat in type I GD.

National health budgets for expensive orphan drugs: Gaucher disease in Israel as a model

Drugs for orphan diseases are often disproportionately costly, although the patient population is by definition small. In Israel, with a high percentage of Ashkenazi Jews and therefore many patients with Gaucher disease, the expense of enzyme replacement therapy for all patients would be prohibitive. For this reason, with approval of enzyme replacement therapy in Israel, the low-dose regimen (30 U/kg/month), less than one quarter of the manufacturer's original recommended dosage, was instituted as the starting regimen. A Gaucher Committee of medical experts under the auspices of the Ministry of Health determines eligibility for enzyme replacement therapy based on criteria of disease severity. At the advent of 2006, 184 patients in Israel receive enzyme replacement therapy, about one third of all known Israeli patients with Gaucher disease. The national budget provides capitation for each patient to each Sick Fund via a health care basket for severe/expensive treatments. After nearly nine years, the benefits of these innovations include availability of budget for patients requiring enzyme replacement therapy, evidence-based data that low dose is safe and effective, and that untreated mildly affected patients generally continue a benign disease trajectory, but if necessary, have recourse to enzyme replacement therapy, that is, patient care is never compromised. Questionnaires of satisfaction with this system highlight good outcome scores. For countries with limited resources, the use of an impartial committee of experts is recommended, as is long-term surveillance of all patients; maintenance protocols or even drug vacations as enzyme-treated patients approach normalization of disease parameters should be considered.

Identification of Novel Biomarkers for Niemann–Pick Disease Using Gene Expression Analysis of Acid Sphingomyelinase Knockout Mice

Although several therapies are available or being developed for lysosomal storage disorders (LSDs), assessment of therapeutic efficacy is challenged by the lack of markers to assess disease progression and severity. This is particularly true for rare diseases such as LSDs, since natural history data from human populations are often lacking. Herein we describe the use of gene expression analysis in the acid sphingomyelinase-deficient mouse model (ASMKO) of Types A and B Niemann-Pick disease (NPD) to identify novel serum biomarkers. We used microarray and real-time PCR analyses to compare mRNA expression in ASMKO and normal mice in two important sites of pathology, lung and brain, and from these data identified and validated several potential biomarkers. The cytokine MIP-1alpha was markedly elevated in ASMKO mouse serum, and following enzyme replacement therapy (ERT) it was reduced to normal levels. Total iron levels were similarly elevated in ASMKO mice, reflective of the elevated ferritin light chain transcript, and decreased to normal after ERT. Serum growth hormone levels were also elevated in ASMKO mice and were reduced to normal after brain-directed gene therapy, but not ERT. These studies illustrate the value of gene expression analysis for the identification of biomarkers, and provide new insight into the pathobiology of NPD.

Type 2 Gaucher disease: 15 new cases and review of the literature

OBJECTIVES

To provide a description of type 2 Gaucher disease. To attempt to define type 2 Gaucher disease within the spectrum of early-onset neuronopathic Gaucher disease.

BACKGROUND

Type 2 Gaucher disease is a rare disorder due to glucocerebrosidase deficiency that comprises a rapidly progressing neurological degeneration associated with visceral signs. Most data collected rely on the description of single cases or siblings. Cases of perinatal-lethal Gaucher disease are frequently considered as type 2 Gaucher patients, though the clinical presentation is different.

METHODS

We retrospectively studied the clinical history of 15 original acute Gaucher disease patients and reviewed the available data of 104 published cases of early-onset neuronopathic Gaucher disease, including 61 patients with the acute type and 43 cases of the perinatal-lethal form.

RESULTS

The neurological presentation of type 2 Gaucher disease is homogeneous and characterized by precocious, severe, and rapidly progressive brainstem degeneration in the foreground. The most frequent initial signs are hyperextension of the neck, swallowing impairment, and strabismus. Provoked asphyxic episodes generally appear in a second time. They are followed by prolonged spontaneous apneas that seem to be the main pejorative feature. Other neurological signs may be observed, but epilepsy, myoclonic epilepsy/myoclonus, trismus, stridor, and progressive microcephaly are less characteristic. Psychomotor regression may occur, but is not a typical feature of the disease onset. Chronic or subacute pulmonary disease predominates in the visceral involvement. Hepatosplenomegaly, failure to thrive, thrombocytopenia, and anemia are the other remarkable, albeit non-specific, features. The inflammatory component of Gaucher disease is underlined by the addition of unexplained fever to this systemic clinical picture. The natural history and particular signs of perinatal-lethal Gaucher disease do not belong to the type 2 Gaucher disease phenotype.

CONCLUSION

Type 2 Gaucher disease is a clinically homogeneous entity. The specificity of the neurological involvement is sufficient to suspect the diagnosis at the onset of the disease. Type 2 and perinatal-lethal Gaucher diseases are easily distinguishable in most cases.

Improving multiple behaviors for colorectal cancer prevention among african american church members

The WATCH (Wellness for African Americans Through Churches) Project was a randomized trial comparing the effectiveness of 2 strategies to promote colorectal cancer preventive behaviors among 587 African American members of 12 rural North Carolina churches. Using a 2 X 2 factorial research design, the authors compared a tailored print and video (TPV) intervention, consisting of 4 individually tailored newsletters and targeted videotapes, with a lay health advisor (LHA) intervention. Results showed that the TPV intervention significantly improved (p <.05) fruit and vegetable consumption (0.6 servings) and recreational physical activity (2.5 metabolic task equivalents per hour) and, among those 50 and older (n = 287), achieved a 15% increase in fecal occult blood testing screening (p =.08). The LHA intervention did not prove effective, possibly because of suboptimal reach and diffusion.