Accumulation and distribution of α-synuclein and ubiquitin in the CNS of Gaucher disease mouse models

Gaucher disease, a prevalent lysosomal storage disease, is caused by insufficient activity of acid β-glucosidase (GCase) and resultant glucosylceramide accumulation. Recently in Parkinson disease (PD) patients, heterozygous mutations in GCase have been associated with earlier onset and more progressive PD. To understand the pathogenic relationships between GCase variants and Parkinsonism, α-synuclein and ubiquitin distributions and levels in the brains of several mouse models containing GCase variants were evaluated by immunohistochemistry. Progressive α-synuclein and ubiquitin aggregate accumulations were observed in the cortex, hippocampus, basal ganglia, brainstem, and some cerebellar regions between 4 and 24 weeks in mice that were homozygous for GCase [D409H (9H) or V394L (4L)] variants and also had a prosaposin hypomorphic (PS-NA) transgene. In 4L/PS-NA and 9H/PS-NA mice, this was coincident with progressive neurological manifestations and brain glucosylceramide accumulation. Ultrastructural studies showed electron dense inclusion bodies in neurons and axons of 9H/PS-NA brains. α-synuclein aggregates were also observed in ventricular, brainstem, and cerebellar regions of older mice (>42-weeks) with the GCase variant (D409H/D409H) without overt neurological disease. In a chemically induced GCase deficiency, α-synuclein aggregates and glucosylceramide accumulation also occurred. These studies demonstrate a relationship between glucosylceramide accumulation and α-synuclein aggregates, and implicate glucosylceramide accumulation as risk factor for the α-synucleinopathies.

Molecular characterization of a new deletion of the GBA1 gene due to an inter Alu recombination event

Gaucher disease is the most frequent lysosomal storage disorder due to the autosomal recessive deficiency of acid β-glucosidase. More than 300 mutations in the GBA1 gene have been described. However only one large deletion of the GBA1 gene has been reported to date. Here, using a combination of different experimental approaches including PCR, sequencing and Southern blot analysis, we describe the identification and characterization of a new large deletion of the GBA1 gene due to an inter Alu recombination event.

Gaucher disease with foamy transformed macrophages and erythrophagocytic activity

Foamy transformation of macrophages is typically seen in lysosomal storage disorders in patients with Niemann-Pick disease, but foamy Gaucher cells (GC) were previously reported only once, in the autopsy report. Although the majority of stored glucocerebroside in GC is of erythrocyte origin, apparent erythrophagocytosis by GC in bone marrow is an unusual finding. Here, we describe the case of an adult non-Jewish Caucasian male with a heterozygous Gaucher disease type 1 (mutations c.1226A>G and c.1448T>C in the GBA1 gene) who presented with atypical morphology of GC on bone marrow examination. Approximately 15% of his GC showed a notable erythrophagocytic activity or unusual appearance of foamy transformed macrophages with a great number of vacuoles and erythrocyte rests in the cytoplasm. This report highlights the fact that morphological examination of cells and tissue specimens is very helpful in the diagnosis of a storage disorder but that confirmatory testing for specific diseases should always follow. Moreover, it is now clear that Gaucher disease should be a part of the differential diagnosis of foamy transformed macrophages.

Gaucher's disease in Lithuania: its diagnosis and treatment

Gaucher's disease is a lysosomal storage disease caused by the lack of beta-glucocerebrosidase enzyme, leading to the accumulation of glucocerebroside. Gaucher's disease is the most frequent type of sphingolipidosis as well as the most frequent lysosomal disease. Clinically, two forms of Gaucher's disease are defined: nonneuronopathic form, so-called type 1, characterized by hepatosplenomegaly, thrombocytopenia, anemia, and osteopenia, and neuronopathic form, known as types 2 and 3, which are also characterized by hepatosplenomegaly, hematological and bone changes; however, involvement of the central nervous system dominates in the clinical picture. Severe deficiency of beta-glucocerebrosidase activity allows confirming the diagnosis based on the clinical picture or the findings of bone marrow examination. Treatment with human glucocerebrosidase was introduced in 1991. Clinically good results are achieved: not only accumulation of glucocerebroside is stopped, but also positive changes in the reticuloendothelial system and an improvement in development and hematological parameters of children are observed as well as the development of bone lesions is reduced. To date, Gaucher's disease has been diagnosed in 8 patients in Lithuania: 3 persons have type 3 and 5 have type 1 disease. Enzyme replacement therapy was started in 2001, and currently 6 persons are being treated. In majority of patients, Gaucher's disease was suspected after exclusion of other possible proliferative diseases. All patients within the first or second year of treatment achieved the therapeutic goals, namely: normalization of hematological parameters, reduction in liver and spleen volumes, and bone pain relief.

Glycosphingolipids and insulin resistance

Glycosphingolipids are structural membrane components, residing largely in the plasma membrane with their sugar-moieties exposed at the cell's surface. In recent times a crucial role for glycosphingolipids in insulin resistance has been proposed. A chronic state of insulin resistance is a rapidly increasing disease condition in Western and developing countries. It is considered to be the major underlying cause of the metabolic syndrome, a combination of metabolic abnormalities that increases the risk for an individual to develop Type 2 diabetes, obesity, cardiovascular disease, polycystic ovary syndrome and nonalcoholic fatty liver disease. As discussed in this chapter, the evidence for a direct regulatory interaction of glycosphingolipids with insulin signaling is still largely indirect. However, the recent finding in animal models that pharmacological reduction of glycosphingolipid biosynthesis ameliorates insulin resistance and prevents some manifestations of metabolic syndrome, supports the view that somehow glycosphingolipids act as critical regulators, Importantly, since reductions in glycosphingolipid biosynthesis have been found to be well tolerated, such approaches may have a therapeutic potential.

Gaucher disease and parkinsonism, a molecular link theory

Mutant GBA was found recently to be the most prevalent risk factor for familial parkinsonism. The two diseases do not share common symptoms and there is no direct pathway to explain the mechanism by which GBA mutations can confer the risk. Increased burden on the degradative pathway caused by defective glucocerebrosidase, or toxic side effects of glycosylated lipids accumulation were proposed to explain brain damage. Both hypotheses are not sufficient to explain the linkage. In order to develop a more inclusive theory we introduced into the model the prion theory and the second hit. Other possibilities are also brought into consideration.

Misdiagnosis of Niemann-Pick disease type C as Gaucher disease

Niemann-Pick disease type C (NPC) is a model for inborn errors of metabolism whose gene product mediates molecular trafficking rather than catabolizing macromolecules, as in classic lipidoses. We report the case of an infant who presented with hepatosplenomegaly without neurological abnormalities. Decreased activity of acid β-glucosidase and elevated serum chitotriosidase and tartrate-resistant acid phosphatase on repeated measurements led to initial diagnosis of Gaucher disease (GD). Failure to respond to enzyme replacement therapy after one year, however, put the diagnosis in question. Cholesterol esterification assays in cultured skin fibroblasts and NPC gene analysis led to the correct diagnosis of NPC. The patient had markedly reduced cholesterol esterification and was a compound heterozygote for a known and a novel mutation in the NPC gene (395delC and 2068insTCCC), which are both predicted to lead to protein truncation. Although the full phenotype of NPC involves hepatosplenomegaly and neurodegenerative disease, the initial presentation in a pediatric patient may be restricted to visceral disease. Of interest, this patient had decreased activity of leukocyte acid β-glucosidase activity and elevated serum chitotriosidase to levels often seen in GD. Although acid β-glucosidase activity in leukocytes was low, it was in the normal range in skin fibroblasts. Therefore, diagnostic delay may occur in NPC due to false positive testing for GD. Diagnosis of NPC requires a high index of suspicion and should be considered in a patient with hepatosplenomegaly even in the absence of neurodevelopmental signs. Prompt diagnosis will become increasingly important as effective therapies are developed for NPC.

Pulmonary hemorrhage in type 3 Gaucher disease: a case report

A 2-year-old boy with type 3 Gaucher disease (GD) on treatment with enzyme replacement therapy (ERT) was found dead in bed having been apparently well the night before. At the time of diagnosis, he had significant respiratory symptoms (severe and persistent bouts of coughing) that had been attributed to Gaucher lung infiltration and that were controlled by inhaled and orally administered steroids. These symptoms had begun to reappear just prior to death. Postmortem revealed extensive pulmonary hemorrhage and intra-alveolar collections of Gaucher cells. There was very little evidence of GD elsewhere. Death was ascribed to pulmonary hemorrhage secondary to GD. The pathogenesis was unclear. To the best of our knowledge, this is the first case of isolated pulmonary hemorrhage secondary to GD and may represent a hitherto unrecognized complication of this condition. Given the apparent temporal relationship, we propose that it represented a severe, terminal event in the course of Gaucher lung disease.

A monozygotic twin pair with highly discordant Gaucher phenotypes

We describe monozygotic twin sisters, born to consanguineous Moroccan parents, who are highly discordant for the manifestations of Gaucher disease. Both carry Gaucher genotype N188S/N188S. One has severe visceral involvement, epilepsy, and a cerebellar syndrome. Her twin does not manifest any symptoms or signs of Gaucher disease but suffers from type 1 diabetes mellitus. The concurrence of a mild Gaucher mutation with a severe phenotype, as well as the occurrence of highly discordant phenotypes in a pair of monozygotic twins, is discussed.

Glucocerebrosidase is present in α-synuclein inclusions in Lewy body disorders

Mutations in the gene encoding the lysosomal enzyme glucocerebrosidase, known to cause Gaucher disease (GD), are a risk factor for the development of Parkinson disease (PD) and related disorders. This association is based on the concurrence of parkinsonism and GD, the identification of glucocerebrosidase mutations in cohorts with PD from centers around the world, and neuropathologic findings. The contribution of glucocerebrosidase to the development of parkinsonian pathology was explored by studying seven brain samples from subjects carrying glucocerebrosidase mutations with pathologic diagnoses of PD and/or Lewy body dementia. Three individuals had GD and four were heterozygous for glucocerebrosidase mutations. All cases had no known family history of PD and the mean age of disease onset was 59 years (range 42-77). Immunofluorescence studies on brain tissue samples from patients with parkinsonism associated with glucocerebrosidase mutations showed that glucocerebrosidase was present in 32-90% of Lewy bodies (mean 75%), some ubiquitinated and others non-ubiquitinated. In samples from seven subjects without mutations, <10% of Lewy bodies were glucocerebrosidase positive (mean 4%). This data demonstrates that glucocerebrosidase can be an important component of α-synuclein-positive pathological inclusions. Unraveling the role of mutant glucocerebrosidase in the development of this pathology will further our understanding of the lysosomal pathways that likely contribute to the formation and/or clearance of these protein aggregates.

Eliglustat tartrate, an orally active glucocerebroside synthase inhibitor for the potential treatment of Gaucher disease and other lysosomal storage diseases

Eliglustat tartrate (Genz-112638), currently under development by Genzyme Corp, is a glucocerebroside (glucosylceramide) synthase inhibitor for the treatment of Gaucher disease and other lysosomal storage disorders. Gaucher disease is an inherited defect of lysosomal functions caused by mutations in the GBA1 gene leading to accumulation of glucocerebroside, primarily in macrophages. Gaucher disease is characterized by visceromegaly and skeletal complications, including osteoporosis and painful episodes of osteonecrosis. In vitro studies demonstrated that, following exposure to eliglustat tartrate, the abundance of GM1 and GM3 gangliosides in cultured human erythroleukemia cells and murine melanoma cells was decreased. In vivo, eliglustat tartrate administered to Asp409Val/null mice lowered the concentrations of glucocerebroside in the liver, lung and spleen and reduced the number of Gaucher cells in the liver. In a phase Ib clinical trial in healthy volunteers, plasma glucocerebroside concentrations were decreased after dosing with eliglustat tartrate, and in phase II clinical trials in patients with type 1 (non-neuronopathic) Gaucher disease, spleen and liver volumes were diminished. Patients also demonstrated improved bone mineral density, correction of abnormal bone marrow signal with MRI and normalization of glucocerebroside and ganglioside GM3 levels. Eliglustat tartrate is orally active and, with potent effects on the primary identified molecular target for type 1 Gaucher disease and other glycosphingolipidoses, appears likely to fulfill high expectations for clinical efficacy.

The neurological manifestations of Gaucher disease type 1: the French Observatoire on Gaucher disease (FROG)

BACKGROUND

Gaucher disease (GD), the most prevalent inherited lysosomal storage disorder, is caused by deficient glucocerebrosidase activity. Type 1 GD (GD1), the most common variant, is classically considered non-neuronopathic.

METHODS

We performed a national cross-sectional observational survey-the French Observatoire on Gaucher Disease (FROG)-in patients with GD1 between March 2005 and September 2006. The study included all patients over 18 years of age with confirmed GD1 who attended participating centers for regular follow-up.

RESULTS

One hundred and five patients were included, in whom we studied the prevalence and characteristics of relevant neurological symptoms associated with the neuraxis. Of these, 51 (49%) GD1 patients presented at least one neurological symptom. Four patients (4%) had Parkinson disease and 22 (21%) presented with at least one parkinsonian sign or at least one sign frequently associated with Parkinson disease. Five patients (5%) had a previous diagnosis of peripheral neuropathy. Other central nervous system symptoms were recorded in 20 (19%) patients and other peripheral nervous system symptoms in 39 (37%) patients.

CONCLUSIONS

These data challenge the current classification of GD, and suggest that the three forms of GD each involve a different profile of neurological manifestations.

'Maybe it would be better if you spoke to my mother?' - genetic counseling and personal experience

This is the narratives of a family physician and a teacher of Medical Ethics, who herself suffers from Gaucher's disease. She was asked by a colleague to give an advice to a couple trying to decide whether to terminate a pregnancy of a fetus "like her". The ethical, emotional and communicational challenges of the conversation are described in this essay.

Neuronopathic Gaucher disease: demographic and clinical features of 131 patients enrolled in the International Collaborative Gaucher Group Neurological Outcomes Subregistry

OBJECTIVE

To describe demographic, genetic, and clinical characteristics of patients with neuronopathic Gaucher disease (NGD).

METHODS

All patients enrolled in the Neurological Outcomes Subregistry of the International Collaborative Gaucher Group (ICGG) Gaucher Registry as of June 2007 were identified.

RESULTS

The study cohort comprised 131 patients from 17 countries who were enrolled in the Neurological Outcomes Subregistry. The onset of neurological manifestations had occurred before 2 years of age in 47% (61 out of 131 patients), 2 years of age or older in 41% (54 out of 131), and could not be ascertained in the remaining 12% (16 out of 131). The most common manifestations were inability to look to the extreme up or down (45%, 55 out of 123), abnormally slow object tracking (43%, 53 out of 123), convergent squint (36%, 44 out of 121), and ataxia (15 to 20%, 18-27 out of 117). Seizures were reported in 19 out of 122 patients (16%), and myoclonic seizures were reported in 3 out of 121 patients (2%). The most common genotypes were L444P/L444P (76 out of 108, 70%), L444P/D409H (9 out of 108, 8%), D409H/D409H (8 out of 108, 7%), and L444P/rare allele (6 out of 108, 6%); full sequencing was not performed in all patients.

CONCLUSIONS

Neurological manifestations of GD often begin to appear before the age of 2 years. The most common neurological signs and manifestations are brainstem abnormalities and fine motor dysfunction. The most common genotype is L444P/L444P.

Hyperferritinemia and iron overload in type 1 Gaucher disease

Hyperferritinemia occurs in Gaucher disease but its clinical spectrum or its association with systemic iron overload and HFE mutations are not known. In 114 patients with Type 1 Gaucher disease, we determined serum ferritin, transferrin saturation and HFE genotype. The results were correlated with the extent of hepatosplenomegaly, overall Gaucher disease severity score index, and response to enzyme replacement therapy. In a subset of patients with radiological and/or laboratory evidence of systemic iron overload, liver biopsy was performed. There was a mean 3.7-fold elevation of serum ferritin over the upper limit of normal (ULN). Prior splenectomy was associated with most severe hyperferritinemia compared to patients with intact spleen (6.53 x ULN vs. 2.69 x ULN, P = 0.003). HFE genotyping revealed two patients homozygous for H63D mutation and 30% of patients heterozygote carriers of H63D mutation; no patients harbored C282Y mutation; there was no correlation of ferritin with HFE genotype. Ferritin level correlated with liver volume (Pearson correlation coefficient = 0.254, P = 0.035) and it was negatively correlated with hemoglobin (r = -0.315, P = 0.004); there was no relationship with other indicators of Gaucher disease activity. Enzyme replacement therapy (ERT) resulted in amelioration of hyperferritinemia: 707 +/- 898 ng/ml vs. 301 +/- 310 ng/ml (P = 0.001), transferrin saturation remained normal. Three patients were suspected of clinical iron overload, confirmed on liver biopsy. Iron accumulation was variably noted in hepatocytes and Kupffer cells. There is a high prevalence of hyperferritinemia in Type 1 Gaucher disease that is associated with indicators of disease severity, reversed by ERT and is not related to HFE mutations.

Expanding spectrum of the association between Type 1 Gaucher disease and cancers: a series of patients with up to 3 sequential cancers of multiple types--correlation with genotype and phenotype

In Gaucher disease (GD), inherited deficiency of lysosomal glucocerebrosidase due to mutations in GBA1 gene results in accumulation of glucosylceramide in tissue macrophages, systemic macrophage activation, and a complex multisystemic phenotype. We and others have reported an increased risk of multiple myeloma and other malignancies in non-neuronopathic Type 1 GD (GD1). Here, we describe a subset of GD1 patients with multiple malignancies. In our cohort of 403 patients with GD1, nine patients (2.2%) developed two or three different types of cancers either consecutively or simultaneously. Patients were characterized by age at diagnosis of GD1, GBA1 genotype, disease severity, age at cancer diagnosis, enzyme replacement therapy (ERT) status, and splenectomy status. Of the nine patients, six developed two types of malignancies and three had three cancers each. Overall, the hematologic malignancies comprised lymphoma/leukemia (4) and multiple myeloma (4). Nonhematologic malignancies included colon (2), lung (2), thyroid (2), and prostate cancer (1). Of the seven patients who received ERT, the first cancer was diagnosed before initiation of ERT in all but one. Asplenic patients were more likely to have single or multiple cancers compared with patients with intact spleens (P < 0.0072 and P < 0.0203, respectively). Our data strengthen the association of GD1 and cancer and suggest that patients may be at risk of developing multiple malignancies. We found an association between splenectomy and multiple cancers in GD1. It will be of interest to determine whether timely ERT and declining rates of splenectomy will translate into declining rates of multiple and single cancers.

Velaglucerase alfa, a human recombinant glucocerebrosidase enzyme replacement therapy for type 1 Gaucher disease

Gaucher disease (GD) is caused by a deficiency of the lysosomal enzyme glucocerebrosidase, which results in the accumulation of its substrate, glucocerebroside, in macrophages. This excess in lipid storage within macrophages (subsequently recognized as Gaucher cells) leads to the development of disease, which presents clinical features including anemia, thrombocytopenia and hepatosplenomegaly, and can also lead to the development of neurological problems or bone disease. Velaglucerase alfa is a gene-activated human recombinant glucocerebrosidase being developed by Shire Human Genetic Therapies Inc as an enzyme replacement therapy for type 1 GD. In vitro, velaglucerase alfa was internalized by human macrophages more rapidly than imiglucerase, which has been the sole standard of care for GD for over 15 years. Clinical trials in patients with GD demonstrated that the safety and efficacy of velaglucerase alfa appeared to be comparable with historical imiglucerase data, although head-to-head data were unavailable. Recent problems with the production of imiglucerase led to the unanticipated introduction of velaglucerase alfa to patients with GD through a pre-approval expanded access protocol. Whether this will prove beneficial, in terms of uptake and prescribing of the enzyme, remains to be seen in a market dominated by imiglucerase.

Baseline characteristics and outcome in Romanian patients with Gaucher disease type 1

BACKGROUND/AIM

To present clinical and genetic characteristics of all Romanian patients with Gaucher disease type 1, in whom specific diagnosis has been confirmed by enzymatic and molecular methods and to analyze their outcome with and without enzymatic replacement therapy (ERT).

PATIENTS, METHODS

There are fifty patients (F/M - 1.63/1) with Gaucher disease type 1. Clinical status, haemoglobin, thrombocytes, hepatic/splenic volume, bone mineral density and severity score were assessed at baseline and every six months thereafter. Thirty-nine patients (78%) received imiglucerase (44.4+/-13.6 U/kg/2 weeks) for 3.1+/-1.4 years.

RESULTS

Based on general prevalence data, our group represents 22.7% of the expected total number of patients with Gaucher disease type 1 in Romania. Mean age was 15.5 years at clinical onset and 28.9 years at confirmation of diagnosis. The genotype N370S/L444P was frequent in our group (35.9% of alleles). Anaemia, thrombocytopenia, splenomegaly and bone disease were present at 38%, 70%, 100% and 84%, respectively. Mean values for haemoglobin, thrombocytes, hepatic volume and chitotriosidase normalized after 0.5, 1.5, 2.5 and 3 years of ERT, respectively. Splenomegaly regressed from 14.4 x N (normal) to 3.06 x N over four years of treatment. Bone disease was ameliorated under ERT, yet bone mineral density worsened in patients treated with 30 U/kg/2 weeks.

CONCLUSIONS

The genotype N370S/L444P is frequent in our patients, in line with the severe phenotypes. ERT improved haematological parameters and visceromegaly, without a clear benefit for bone mineral density. To attain therapeutic goals, an early treatment start with optimal dosage is mandatory.

The risk of Parkinson's disease in type 1 Gaucher disease

In Gaucher disease, defective lysosomal glucocerebrosidase due to mutations in the GBA1 gene results in lysosomal accumulation of glucocerebroside in mononuclear phagocytes and a multisystemic phenotype. Observations of occurrence of Parkinson's disease in some patients with non-neuronopathic type 1 Gaucher disease (GD1) and their first degree relatives has led to the identification of GBA1 heterozygous mutations as a genetic risk factor for idiopathic Parkinson's disease (PD). However, the magnitude of risk of PD in patients with known GD1 has not been determined, and it is not known whether GD1/PD represents a specific sub-phenotype of GD1 with distinctive genotype/phenotype characteristics. We estimated the risk of PD in a cohort of 444 consecutively evaluated patients with GD1 compared to that in the general population. Eleven patients developed parkinsonian syndrome during a 12-year follow-up period. The adjusted life-time risk ratio of PD in GD1 compared to that in the general population was 21.4 [95% confidence interval (95% CI) 10.7-38.3], with a higher risk in men compared to women. In our cohort, GD1/Parkinson's disease phenotype (GD1/PD) was characterized by higher GD1 severity score, due to higher incidence of avascular osteonecrosis. The clinical spectrum of PD varied from mild to potentially life-threatening disease. All but one patient with GD1/PD phenotype had at least one N370S GBA1 allele. In conclusion, compared to the general population, patients with GD1 have an almost 20-fold increased life-time risk of developing PD.

[Phenotype and mutational spectrum in Tunisian pediatric gaucher disease]

BACKGROUND

Gaucher disease (GD) is a sphingolipidosis with heterogeneous phenotypic expression. The vital and / or functional prognosis may be threatened by an early visceral severe involvement in type 1 or a neurological degeneration in the more rarest neuroneupathic forms. The phenotypic and genotypic data regarding Gaucher disease are poorly known in Maghrebian countries; they are even less for pediatric forms. THE AIM of the study is to highlight the specific phenotypic and genotypic changing among the widest Gaucher pediatric cohort in the Tunisian population.

METHODS

a restrospective study of a sample oh children in voluved by gaucher disease.

RESULTS

Twenty one cases of GD were identified, divided into 13 cases with type 1, 5 with type 3 and 3 children with acute neurological form. The first symptoms occurred before 1 year age in one third of patients with type IGD. The clinical phenotype was severe according to the high severity score index and proportion of growth retardation. Portal hypertension was found in 8 patients. Three type 3 GD patients died before occurrence of the neurological signs. The phenotype was intermediate between the classic type 2 GD and its perinatal lethal variant. Three patients were treated with enzyme replacement therapy and 4 others had allogenic bone marrow transplantation with a favorable outcome. Three mutations dominate the genotypic spectrum of GD in this cohort. Additionally to the N370 mutation, L444P and RecNciI mutations seem to occur more frequently compared to the GD forms presenting in adulthood.

CONCLUSION

This data confirm the particular severity of Gaucher disease manifesting in childhood. This was enhanced through the high frequency of severe mutations. Further studies on largest cohort are needed to more clarify the phenotypic and genotypic features of Gaucher disease in Tunisia.

In silico and functional studies of the regulation of the glucocerebrosidase gene

In Gaucher disease (GD), the inherited deficiency of glucocerebrosidase results in the accumulation of glucocerebroside within lysosomes. Although almost 300 mutations in the glucocerebrosidase gene (GBA) have been identified, the ability to predict phenotype from genotype is quite limited. In this study, we sought to examine potential GBA transcriptional regulatory elements for variants that contribute to phenotypic diversity. Specifically, we generated the genomic sequence for the orthologous genomic region ( approximately 39.4kb) encompassing GBA in eight non-human mammals. Computational comparisons of the resulting sequences, using human sequence as the reference, allowed the identification of multi-species conserved sequences (MCSs). Further analyses predicted the presence of two putative clusters of transcriptional regulatory elements upstream and downstream of GBA, containing five and three transcription factor-binding sites (TFBSs), respectively. A firefly luciferase (Fluc) reporter construct containing sequence flanking the GBA gene was used to test the functional consequences of altering these conserved sequences. The predicted TFBSs were individually altered by targeted mutagenesis, resulting in enhanced Fluc expression for one site and decreased expression for seven others sites. Gel-shift assays confirmed the loss of nuclear-protein binding for several of the mutated constructs. These identified conserved non-coding sequences flanking GBA could play a role in the transcriptional regulation of the gene contributing to the complexity underlying the phenotypic diversity seen in GD.

An unusual presentation of Gaucher's disease: aortic valve fibrosis in a patient homozygous for a rare G377S mutation

Gaucher's disease (GD) has variable presentations, but cardiac involvement is a generally uncommon clinical manifestation of the disease. In the past 25 years, the underlying genetic disorder in GD has been well characterized, with almost 300 mutations identified in the glucocerebrosidase gene (GBA). Nevertheless, clear genotype-phenotype correlations have been confirmed only for the most frequent mutations. We present a female patient, who was known to have aortic valve pathology from the age of 30. Despite medical follow up, at the age of 60 she presented with heart failure (NYHA III). At that time echocardiography showed severe fibrosed aortic valve stenosis. Valvuloplasty was planned, when thrombocytopenia, previously considered to be autoimmune, became severe. Anemia and leukopenia were also noted. Moderate splenomegaly and severe bone marrow infiltration were found on MRI. Bone marrow aspiration revealed typical Gaucher cells and the enzyme activity assay confirmed the diagnosis. DNA investigation showed that the patient is homozygous for the G377S mutation. To our knowledge, of all mutations identified so far, only homozygosity for the D409H mutation has been associated with cardiovascular valvular disease in patients with a rare type 3c GD. G377S, found in our patient, is a rare mutation, previously reported as a 'mild' mutation, because of the finding that homoallelic patients were essentialy asymptomatic or had mild disease. Our patient, also homozygous for G377S mutation, had a severe form of type 1 GD, with rare cardiac valve involvement, which is a previously unreported clinical presentation for this mutation. This case further proves that patients with the same genotypes can have different phenotypes, emphasizing the influence of other genetic and/or environmental factors.

[High dose of enzyme replacement therapy was successful for the pulmonary involvement in a case of type 2 Gaucher disease]

Pulmonary involvement is a serious complication in Gaucher disease, as is neuronopathic involvement. Few reports are available, however, on the frequency, clinical course and therapy for pulmonary involvement in patients with Gaucher disease. We report a case of type 2 Gaucher disease with severe hepatosplenomegaly, anemia, hypertonia, and psychomotor retardation. The diagnosis of Gaucher disease was confirmed by the presence of Gaucher cells in bone marrow and low serum beta-glucocerebrosidase activity (patient, 0.8; control, 4.1-9.7 nmol/mg.protein/hr) at the age of 1 year. The patient's genotype is L444P/unknown. Enzyme replacement therapy (ERT) with intravenous imiglucerase at 78 U/kg/2weeks was started, and hepatosplenomegaly and laboratory abnormalities were markedly improved after 6 months of therapy. After 8 months of therapy, respiratory impairment appeared together with a decrease of tidal volume and low SpO2 during sleep. Serum acid phosphatase and angiotensin converting enzyme levels mildly increased, and radiological findings showed bilateral ground-glass appearance without signs of respiratory infection. With the diagnosis of progressive pulmonary involvement in Gaucher disease, we increased the dosage of imiglucerase from 50 to 75 U/kg/2 weeks. After a month, respiratory symptoms and CT findings of ground-glass appearance remarkably improved, but interlobular septal and intralobular interstitial thickening persisted. The maximum permitted dosage of imiglucerase in Japan is 60 U/kg/2 weeks. Based on our experience with this case, we propose that a higher ERT dosage would be uselul for serious pulmonary involvement.

[An analysis of mutations causing Gaucher disease in Chinese population]

OBJECTIVE

To review and investigate the relationship of genotype and phenotype in Chinese patients with Gaucher disease (GD).

METHODS

The samples were first screened for known mutations as reported previously in Chinese population. Long chain PCR and nested PCR were employed to amplify the segments of glucocerebrosidase functional gene in patients with unknown mutant alleles. The products of nested-PCR were subjected to DNA sequencing to detect the new mutations.

RESULTS

Forty kinds of mutations were detected in this panel of patients. The L444P mutation was the most common one accounting for 33.0% of mutant alleles. It was followed by F213I, N188S, V375L and M416V.

CONCLUSION

There are at least 40 mutations in Chinese GD patients. The spectrum of mutation is significantly different from that in Caucasians. 70% of mutant alleles have been characterized. It becomes feasible to make clinical and prenatal diagnoses through gene analysis.

Type II Gaucher disease manifesting as haemophagocytic lymphohistiocytosis

Haemophagocytic lymphohistiocytosis (HLH) is a rare and rapidly progressive disease which, untreated, invariably leads to death. Gaucher disease is a rare lysosomal storage disorder. The acute neuronopathic variant; type II, is also rapidly progressive. We report an infant with Gaucher disease type II manifesting as HLH. Immunoblot revealed a deficiency of Munc 13-4, an intracellular protein responsible for docking of secretory lysosomes. This, and other possible pathogenetic mechanisms to explain the link are discussed.

Characterization of Gaucher disease bone marrow mesenchymal stromal cells reveals an altered inflammatory secretome

Gaucher disease causes pathologic skeletal changes that are not fully explained. Considering the important role of mesenchymal stromal cells (MSCs) in bone structural development and maintenance, we analyzed the cellular biochemistry of MSCs from an adult patient with Gaucher disease type 1 (N370S/L444P mutations). Gaucher MSCs possessed a low glucocerebrosidase activity and consequently had a 3-fold increase in cellular glucosylceramide. Gaucher MSCs have a typical MSC marker phenotype, normal osteocytic and adipocytic differentiation, growth, exogenous lactosylceramide trafficking, cholesterol content, lysosomal morphology, and total lysosomal content, and a marked increase in COX-2, prostaglandin E2, interleukin-8, and CCL2 production compared with normal controls. Transcriptome analysis on normal MSCs treated with the glucocerebrosidase inhibitor conduritol B epoxide showed an up-regulation of an array of inflammatory mediators, including CCL2, and other differentially regulated pathways. These cells also showed a decrease in sphingosine-1-phosphate. In conclusion, Gaucher disease MSCs display an altered secretome that could contribute to skeletal disease and immune disease manifestations in a manner distinct and additive to Gaucher macrophages themselves.

In vivo and ex vivo evaluation of L-type calcium channel blockers on acid beta-glucosidase in Gaucher disease mouse models

Gaucher disease is a lysosomal storage disease caused by mutations in acid beta-glucosidase (GCase) leading to defective hydrolysis and accumulation of its substrates. Two L-type calcium channel (LTCC) blockers-verapamil and diltiazem-have been reported to modulate endoplasmic reticulum (ER) folding, trafficking, and activity of GCase in human Gaucher disease fibroblasts. Similarly, these LTCC blockers were tested with cultured skin fibroblasts from homozygous point-mutated GCase mice (V394L, D409H, D409V, and N370S) with the effect of enhancing of GCase activity. Correspondingly, diltiazem increased GCase protein and facilitated GCase trafficking to the lysosomes of these cells. The in vivo effects of diltiazem on GCase were evaluated in mice homozygous wild-type (WT), V394L and D409H. In D409H homozygotes diltiazem (10 mg/kg/d via drinking water or 50-200 mg/kg/d intraperitoneally) had minor effects on increasing GCase activity in brain and liver (1.2-fold). Diltiazem treatment (10 mg/kg/d) had essentially no effect on WT and V394L GCase protein or activity levels (<1.2-fold) in liver. These results show that LTCC blockers had the ex vivo effects of increasing GCase activity and protein in the mouse fibroblasts, but these effects did not translate into similar changes in vivo even at very high drug doses.

Clinical and genetic study of Japanese patients with type 3 Gaucher disease

Information on the phenotypic variations seen in patients with type 3 (chronic neuronopathic) Gaucher disease (GD) is still limited compared with type 1 GD. We retrospectively investigated the clinical features of 42 Japanese patients with type 3 GD. The 42 patients classified as type 3 fell into two groups: those diagnosed as having type 3 GD at diagnosis (group A; n = 24) and those thought to have type 1 at diagnosis but who later developed neurological symptoms (group B; n = 18). The genotype of group A patients varied widely; however, L444P/L444P and L444P/F213I genotypes accounted for 83% in group B. All the patients who did not receive enzyme replacement with alglucerase or imiglucerase (4 in group A, 2 in group B) died. Nineteen patients received enzyme replacement in group A; however, 7 of these died despite the therapy. On the other hand, 14 patients received enzyme replacement alone in group B and 13 of them survived. Among the ERT-treated patients who survived, only one of 12 in group A and 12 out of 13 in group B can walk unaided. In conclusion, some Japanese GD patients who are thought to have type 1 at diagnosis develop neurological symptoms during their clinical course, and careful observation is essential for patients with characteristic genotypes. Moreover, enzyme replacement alone might not have a sufficient effect on the early onset neurological symptoms in type 3 patients. A different treatment strategy is needed to improve the prognosis of these patients.

Type I Gaucher disease (GDI) in three siblings: enzyme replacement treatment (ERT) required

(Full text is available at http://www.manu.edu.mk/prilozi). This is a family of three children, born to healthy Macedonian parents after uneventful pregnancies and delivery. The index child was an eight-year-old girl admitted for abdominal discomfort and distension: the spleen was 14cm below the costal margin (BCM), the liver 8cm BCM. No bone pain or pathology was reported. There was mild pancytopaenia (hemoglobin 11.2 gm/L; WBC counts 4.6 x 10;3; platelets 70 x 10;3). Liver function tests, renal ultrasound, bone scan, and a chest radiograph were within normal limits. Bone marrow analysis in this child and her two brothers (11 and 6.5 years old) revealed Gaucher cells. Both brothers had only mild anaemia, but the older brother had been splenectomized prior to diagnosis of GD1. Enzyme analysis revealed low activity (2.59, 1.62, and 2.55 nmol/h/mg protein, respectively); plasma chitotriosidase levels were also elevated. Genetic testing revealed homozygosity for the N370S/N370S mutation in all three siblings. In the absence of available enzyme replacement treatment (ERT), the girl was splenectomized. Removing an important immune organ (the spleen) introduces further risk for the patients. In addition, this does not solve the bone involvement characteristic for GD. ERT should be introduced for all GD1 patients in Macedonia. Key words: Gaucher disease, N370S mutation, siblings, enzyme replacement therapy.

Glucocerebrosidase mutations in clinical and pathologically proven Parkinson's disease

Mutations in the glucocerebrosidase gene (GBA) are associated with Gaucher's disease, the most common lysosomal storage disorder. Parkinsonism is an established feature of Gaucher's disease and an increased frequency of mutations in GBA has been reported in several different ethnic series with sporadic Parkinson's disease. In this study, we evaluated the frequency of GBA mutations in British patients affected by Parkinson's disease. We utilized the DNA of 790 patients and 257 controls, matched for age and ethnicity, to screen for mutations within the GBA gene. Clinical data on all identified GBA mutation carriers was reviewed and analysed. Additionally, in all cases where brain material was available, a neuropathological evaluation was performed and compared to sporadic Parkinson's disease without GBA mutations. The frequency of GBA mutations among the British patients (33/790 = 4.18%) was significantly higher (P = 0.01; odds ratio = 3.7; 95% confidence interval = 1.12-12.14) when compared to the control group (3/257 = 1.17%). Fourteen different GBA mutations were identified, including three previously undescribed mutations, K7E, D443N and G193E. Pathological examination revealed widespread and abundant alpha-synuclein pathology in all 17 GBA mutation carriers, which were graded as Braak stage of 5-6, and had McKeith's limbic or diffuse neocortical Lewy body-type pathology. Diffuse neocortical Lewy body-type pathology tended to occur more frequently in the group with GBA mutations compared to matched Parkinson's disease controls. Clinical features comprised an early onset of the disease, the presence of hallucinations in 45% (14/31) and symptoms of cognitive decline or dementia in 48% (15/31) of patients. This study demonstrates that GBA mutations are found in British subjects at a higher frequency than any other known Parkinson's disease gene. This is the largest study to date on a non-Jewish patient sample with a detailed genotype/phenotype/pathological analyses which strengthens the hypothesis that GBA mutations represent a significant risk factor for the development of Parkinson's disease and suggest that to date, this is the most common genetic factor identified for the disease.

The underrecognized progressive nature of N370S Gaucher disease and assessment of cancer risk in 403 patients

Mutations in GBA1 gene that encodes lysosomal glucocerebrosidase result in Type 1 Gaucher Disease (GD), the commonest lysosomal storage disorder; the most prevalent disease mutation is N370S. We investigated the heterogeneity and natural course of N370S GD in 403 patients. Demographic, clinical, and genetic characteristics of GD at presentation were examined in a cross-sectional study. In addition, the relative risk (RR) of cancer in patients compared with age-, sex-, and ethnic-group adjusted national rates of cancer was determined. Of the 403 patients, 54% of patients were homozygous (N370S/N370S) and 46% were compound heterozygous for the N370S mutation (N370S/other). The majority of N370S/N370S patients displayed a phenotype characterized by late onset, predominantly skeletal disease, whereas the majority of N370S/other patients displayed early onset, predominantly visceral/hematologic disease, P < 0.0001. There was a striking increase in lifetime risk of multiple myeloma in the entire cohort (RR 25, 95% CI 9.17-54.40), mostly confined to N370S homozygous patients. The risk of other hematologic malignancies (RR 3.45, 95% CI 1.49-6.79), and overall cancer risk (RR 1.80, 95% CI 1.32-2.40) was increased. Homozygous N370S GD leads to adult-onset progressive skeletal disease with relative sparing of the viscera, a strikingly high risk of multiple myeloma, and an increased risk of other cancers. High incidence of gammopathy suggests an important role of the adaptive immune system in the development of GD. Adult patients with GD should be monitored for skeletal disease and cancers including multiple myeloma.

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.

Life expectancy in Gaucher disease type 1

We estimated life expectancy at birth for Gaucher disease type 1 (GD1) patients by comparing survival data from GD1 patients enrolled in ICGG Gaucher Registry to the U.S. population using standard life table methods. 2,876 GD1 patients had 102 reported deaths in 13,509 person-years of follow-up. Estimated life expectancy at birth was 68 y, compared with 77 y in reference population; splenectomized patients, 64 y; nonsplenectomized, 72 y. Causes of death for 63/102 patients were malignancy (17/63), cardiovascular (11/63), and cerebrovascular (8/63). Estimated life expectancy at birth for GD1 patients was approximately 9 y less than reference population. Malignancies did not contribute to shortened life expectancy.

Phenotypic heterogeneity of N370S homozygotes with type I Gaucher disease: an analysis of 798 patients from the ICGG Gaucher Registry

Gaucher disease is a lysosomal storage disorder caused by a deficiency of the enzyme acid beta-glucosidase. The most prevalent mutant genotype in type I Gaucher disease, N370S/N370S, is commonly thought to confer a mild phenotype presenting in adulthood. To characterize a subset of more severely affected N370S homozygotes, we assessed the phenotypes at or near the time of diagnosis of all N370S homozygotes with available data enrolled in the International Collaborative Gaucher Group Gaucher Registry. N370S compound heterozygotes were analyzed for comparison, as they are expected to present with a more severe phenotype. Of 798 N370S homozygotes and 1,278 N370S compound heterozygotes identified, 32% (251/788) and 65% (820/1269), respectively, were diagnosed before age 20 years. At diagnosis, N370S homozygotes as compared to N370S compound heterozygotes had the following clinical characteristics: irreversible skeletal lesions 17% (34/198) for N370S homozygotes versus 26% (76/290) for N370S compound heterozygotes; anaemia 18% (59/327) versus 29% (145/494); thrombocytopenia 52% (170/327) versus 62% (281/453); hepatomegaly 44% (83/190) versus 72% (141/195); splenomegaly 73% (142/194) versus 91% (178/195); and osteopenia or osteoporosis 48.6% (34/70) versus 51% (25/49). Some N370S homozygotes exhibited more severe clinical manifestations: 9% (29/327) had severe thrombocytopenia; 3% (5/190) had severe hepatomegaly; 11% (22/194) had severe splenomegaly; 7% (18/255) reported bone crises; 11% (8/70) had osteoporosis. In conclusion, N370S homozygosity does not consistently confer a mild, adult-onset phenotype. Gaucher disease patients with the N370S/N370S genotype exhibit a high degree of phenotypic heterogeneity and some may be at risk for early disease onset and severe clinical manifestations.

A benchmark analysis of the achievement of therapeutic goals for type 1 Gaucher disease patients treated with imiglucerase

To assess the extent to which patients with type 1 Gaucher disease (GD1) receiving individualized enzyme replacement therapy with imiglucerase attain six defined therapeutic goals. One hundred and ninety-five GD1 patients enrolled in the ICGG Gaucher Registry, all of whom had data available for hemoglobin, platelet count, liver volume, spleen volume, bone pain, and bone crises at first infusion and after 4 years of therapy with imiglucerase, were evaluated for achievement of published therapeutic goals. The proportion of patients who met all six therapeutic goals increased from 2.1% at first infusion to 41.5% at 4 years; > or =5 goals from 12.8% to 76.9%; > or =4 goals from 37.4% to 92.8%; > or =3 goals from 70.8% to 99.0%; and > or =2 goals from 95.4% to 99.5%. All patients met at least one goal at first infusion and after 4 years of treatment. The proportion of patients meeting specific therapeutic goals increased for all parameters between first infusion and 4 years of therapy: platelet count (24.6%-79.5%), spleen volume (25.6%-78.5%), liver volume (45.6%-90.8%), bone pain (62.6-70.3%), hemoglobin (68.2-91.8%), and bone crises (91.8-99.0%). On average, patients who received higher doses of imiglucerase achieved a greater number of therapeutic goals. This analysis provides a benchmark for evaluating the utility of a disease management approach for GD1 based on monitoring achievement of therapeutic goals after treatment with imiglucerase.

Phenotype, diagnosis, and treatment of Gaucher's disease

Gaucher's disease continues to be a model for applications of molecular medicine to clinical delineation, diagnosis, and treatment. Analyses of several thousand affected individuals have broadened the range of the pan-ethnic disease variants, provided initial genotype and phenotype correlations, and established the effectiveness of enzyme therapy. Large numbers of affected individuals worldwide have provided insight into the effect of disease variation related to ethnic origin, prognosis, and outcome. The ability to safely and effectively use enzyme therapy to inhibit or reverse visceral-disease progression and involvement has provided impetus for design of new enzyme therapies, and creation of substrate depletion and pharmacological chaperone strategies. Such innovations could provide interventions that are effective for neuronopathic variants and, potentially, could be more cost effective than other treatments. These developments are novel, clinically important, advancements for patients with other lysosomal storage diseases and genetic diseases.

Carrier Testing for Autosomal- Recessive Disorders

The aim of carrier testing is to identify carrier couples at risk of having offspring with a serious genetic (autosomal recessive) disorder. Carrier couples are offered genetic consultation where their reproductive options, including prenatal diagnosis, are explained. The Ashkenazi Jewish population is at increased risk for several recessively inherited disorders (Tay-Sachs disease, Cystic fibrosis, Canavan disease, Gaucher disease, Familial Dysautonomia, Niemann-Pick disease, Fanconi anemia, and Bloom syndrome). Unlike Tay-Sachs disease, there is no simple biochemical or enzymatic test to detect carriers for these other disorders. However, with the rapid identification of disease-causing genes in recent years, DNA-based assays are increasingly available for carrier detection. Approximately 5% of the world's population carries a mutation affecting the globin chains of the hemoglobin molecule. Among the most common of these disorders are the thalassemias. The global birth rate of affected infants is at least 2 per 1000 (in unscreened populations), with the greatest incidence in Southeast Asian, Indian, Mediterranean, and Middle Eastern ethnic groups. Carriers are detected by evaluation of red cell indices and morphology, followed by more sophisticated hematological testing and molecular analyses. The following issues need to be considered in the development of a carrier screening program: (1) test selection based on disease severity and test accuracy; (2) funding for testing and genetic counselling; (3) definition of the target population to be screened; (4) development of a public and professional education program; (5) informed consent for screening; and (6) awareness of community needs.

Gaucher disease in Arab patients at an Israeli referral clinic

BACKGROUND

With regard to ethnic predilections for Gaucher disease, the most common storage disorder, Ashkenazi Jews are at risk for the non-neuronopathic form (type I), Norbottnian Swedes are at risk for the subacute neuronopathic form (type III), and perhaps Arabs are at risk for the very rare cardiac variant of the subacute neuronopathic form (type IIIc) for which there is a relatively tight genotype-phenotype correlation. Type II, the acute infantile form, being the rarest form, has not been associated with any ethnic predilection.

OBJECTIVES

To examine whether Arab ethnicity influences the Gaucher phenotype.

METHODS

We reviewed the records of all Arab patients in a referral clinic of 586 patients in Israel.

RESULTS

There were 46 patients (7.8%) of Arab ethnicity: 23 (50%) had type I disease, 16 (34.8%) had type IIIc disease, 4 (8.7%) had type IIIb disease, and 3 (6.5%) had type II disease. Type IIIc disease was characterized by genotype-phenotype correlation with homozygosity for the D409H (1342C) mutation. All five Bedouin patients (10.9%) had the R48W (C259T) mutation on at least one allele.

CONCLUSIONS

For all genotypes, disease severity among Arab patients was relatively similar to that reported among other Caucasian patients. Apparently Arab ethnicity does not impact phenotypic expression in Gaucher disease in a unique manner. The predilection for type IIIc may be a result of consanguinity.

An evolutionary and structure-based docking model for glucocerebrosidase-saposin C and glucocerebrosidase-substrate interactions - relevance for Gaucher disease

Gaucher disease, the most prevalent lysosomal storage disorder, is principally caused by malfunction of the lysosomal enzyme glucocerebrosidase (GBA), a 497-amino acid membrane glycoprotein that catalyzes the hydrolysis of glucosylceramide to ceramide and glucose in the presence of an essential 84-residue activator peptide named saposin C (SapC). Knowledge of the GBA structure, a typical (beta/alpha)(8) TIM barrel, explains the effect of few mutations, directly affecting or located near the catalytic site. To identify new regions crucial for proper GBA functionality, we analyzed the interactions of the enzyme with a second (substrate) and a third (cofactor) partner. We build 3D docking models of the GBA-SapC and the GBA-ceramide interactions, by means of methodologies that integrate both evolutive and structural information. The GBA-SapC docking model confirm the implication of three spatially closed regions of the GBA surface (TIM barrel-helix 6 and helix 7, and the Ig-like domain) in binding the SapC molecule. This model provides new basis to understand the pathogenicity of several mutations, such as the prevalent Leu444Pro, and the additive effect of Glu326Lys in the double mutant Glu326Lys-Leu444Pro. Overall, 39 positions in which amino acid changes are known to cause Gaucher disease were localized in the GBA regions identified in this work. Our model is discussed in relation to the phenotype (pathogenic effect) of these mutations, as well as to the enzymatic activity of the recombinant proteins when available. Both data fully correlates with the proposed model, which will provide a new tool to better understand Gaucher disease and to design new therapy strategies.

Pharmacologic chaperoning as a strategy to treat Gaucher disease

We briefly introduce the most common lysosomal storage disorder, Gaucher disease, concisely describe the Food and Drug Administration approved strategies to ameliorate Gaucher disease, and then outline the emerging pharmacologic chaperone strategy that offers the promise to remedy this malady.