Individualization of long-term enzyme replacement therapy for Gaucher disease.

Gaucher disease, the most common lysosomal storage disorder, is a heterogeneous condition affecting multiple organ systems. Patients with nonneuronopathic (type 1) Gaucher disease may suffer from hepatomegaly, splenomegaly, thrombocytopenia, bleeding tendencies, anemia, hypermetabolism, skeletal pathology, growth retardation, pulmonary disease, and decreased quality of life. Enzyme replacement therapy (ERT) with mannose-terminated glucocerebrosidase (imiglucerase, Cerezyme, Genzyme Corporation, Cambridge, MA) reverses or ameliorates many of the manifestations of type 1 Gaucher disease. However, due to the variable pattern and severity of disease, and the uncertain manner of progression, implementation of treatment, choice of initial and maintenance imiglucerase dose, and evaluation of the therapeutic response must be tailored to the individual patient. For the past 14 years, the US Regional Coordinators of the International Collaborative Gaucher Group have individually and collectively developed extensive clinical experience in managing patients with Gaucher disease. In this review, we present recommendations for initial imiglucerase treatment and subsequent dose adjustments based on a schedule of regular assessment and monitoring, and achievement and maintenance of defined therapeutic goals.     

Gaucher disease: complexity in a "simple" disorder

Gaucher disease, the recessively inherited deficiency of the enzyme glucocerebrosidase and the most common sphingolipidosis, has both non-neurological and neuronopathic forms and a continuum of diverse clinical manifestations. Studies of genotype-phenotype correlations reveal significant genotypic heterogeneity among clinically similar patients, and vastly different phenotypes among patients with the same mutations. The region surrounding the glucocerebrosidase gene (GBA) on chromosome 1q is particularly gene-rich, with a highly homologous pseudogene sequence 16 kb downstream. Recombination events within the GBA locus contribute to the etiology of some mutations in Gaucher disease. Studies of patients with Gaucher disease and atypical manifestations, including parkinsonism, myoclonic epilepsy, cardiac involvement and collodion skin, seek to define other genetic or environmental factors contributing to the phenotypes. Recent reports demonstrating an association between Gaucher disease and parkinsonism provide an example of heterozygosity for a Mendelian disorder acting as a risk factor for a complex disease. There are rare patients with Gaucher disease and differing genotypes who develop early onset, treatment-refractory parkinsonism. Neuropathology in a group of these patients showed alpha-synuclein-reactive Lewy bodies in brain regions specifically associated with Gaucher disease. Family studies of these probands suggested that the incidence of parkinsonism might be more frequent in obligate heterozygotes. In a complementary finding, the examination of GBA in autopsy samples from individuals with sporadic Parkinson disease identified alterations in the GBA sequence in 14% of the cohort. These studies provide evidence that altered glucocerebrosidase may contribute to a vulnerability to parkinsonism. Moreover, this research demonstrates how insights from rare, single gene disorders like Gaucher disease can provide a window into the etiology of more common, multifactorial genetic diseases.     

55-Base pair deletion in certain patients with Gaucher disease complicates screening for common Gaucher alleles

Mutations in the glucocerebrosidase gene which result in Gaucher disease can originate from the highly homologous glucocerebrosidase pseudogene. A 55-bp deletion in exon 9, which corresponds to a 55-bp segment absent from the pseudogene, has been identified in patients with Gaucher disease. We have developed a simple polymerase chain reaction (PCR)-based method to detect this 55-bp deletion, and have found this mutation in 3 of 75 DNA samples (4%) collected from patients with Gaucher disease. Commonly used PCR-based screening methods for specific Gaucher mutations frequently make use of primers either within or surrounding the 55-bp gap to selectively distinguish the glucocerebrosidase gene from the pseudogene. However, if the 55-bp deletion in exon 9 occurs, primers will either fail to produce an amplification product or will produce a shortened product which will be falsely attributed to the pseudogene. This could lead to inaccurate genotyping and genetic counseling for some Gaucher patients and their families. We therefore recommend that laboratories using PCR-based screening techniques involving primers in this region initially determine whether this 55-bp sequence is present. © 1996 Wiley-Liss, Inc.     

Gaucher disease and the synucleinopathies

Several recent observations suggest a connection between Gaucher disease, the inherited deficiency of glucocerebrosidase, and the synucleinopathies. Rare patients have been observed who develop both Gaucher disease and parkinsonism. Autopsy studies on these subjects reveal synuclein-positive Lewy bodies and inclusions. An increased incidence of synucleinopathies also has been noted in relatives of Gaucher probands. In complementary studies, screening of patients with parkinsonism has identified a greater than expected frequency of glucocerebrosidase mutations. These glucocerebrosidase mutation carriers have a wide spectrum of associated parkinsonian phenotypes, ranging from classic L-dopa-responsive Parkinson disease to a phenotype more characteristic of Lewy body dementia. Despite this association, the vast majority of Gaucher carriers and patients with Gaucher disease never develop parkinsonism. However, mutations in this gene are likely to be a contributing risk factor in subjects otherwise prone to developing synucleinopathies.     

DNA mutational analysis of type 1 and type 3 gaucher patients: How well do mutations predict phenotype?

The wide spectrum of clinical manifestations resulting from glucocerebrosidase deficiency complicates genetic counseling for Gaucher disease. The identification of mutations in the glucocerebrosidase gene has enabled studies of genotype–phenotype correlation. However, a genotypic analysis of 60 type 1 and type 3 Gaucher patients reveals that the 5 most common Gaucher mutations, N370S, L444P, R463C, 84insG, and IVS2 + 1 G→A, can be found both in patients with and without neurologic manifestations. Moreover, although some generalizations can be made about mutations that are more frequently encountered in particular patient populations, Gaucher patients sharing identical genotypes can exhibit considerable clinical heterogeneity. Thus in considering rationale for population screening one cannot rely solely on PCR determined DNA mutation analysis to reliably predict prognosis in Gaucher disease. © 1994 WiIey-Liss, Inc. © 1994 Wiley-Liss, Inc.     

Enzyme Replacement Therapy in a Gaucher Family

Gaucher disease is a lipid storage disorder due to deficiency of beta glucocerebrosidase. It's an autosomal recessive disease and as a result of this enzyme deficiency, glucocerebroside accumulates in various types of tissues like liver, brain spleen and bone marrow. We aimed to describe the effects of enzyme replacement therapy in three members of a family with Gaucher disease and to emphasize screening of the family members of the patients with Gaucher disease. Furthermore, late diagnosis and treatment in these patients have a minimal effect on improvement of the quality of life, and early diagnosis and treatment are very important in Gaucher disease.     

Molecular analysis of Gaucher disease: screening of patients in the Montreal/Quebec region.

Gaucher disease, the most prevalent lysosomal storage disease, is an autosomal recessive sphingolipidosis resulting from deficient glucocerebrosidase activity. Genomic DNA of the structural gene of glucocerebrosidase from normal individuals and fifteen unrelated patients with the three clinical forms of Gaucher disease from the Montreal/Quebec region were amplified by the polymerase chain reaction technique. Allele-specific oligonucleotide dot blot hybridization and restriction fragment length polymorphism were used to screen for five of the mutations [mutations 120, 370, 415, 444 (Nci), and 463] in exons 5, 9, and 10 of glucocerebrosidase gene. It was noted that all of the patients had at least one of the known mutant alleles. However, 9 patients (9/15 = 60%) had an unknown allele. Mutation 370 in exon 9 was present in the heteroallelic form in eight out of the nine patients with type 1 Gaucher disease, but was present in none of the six patients with type 2 or type 3 Gaucher disease. The Nci mutation in exon 10 was present in the heteroallelic form in three patients with type 1 Gaucher disease and in either the heteroallelic or homoallelic form in all of the six patients with type 2 or type 3 Gaucher disease. The 415/Nci mutations were found in a mildly affected 29-year-old patient with type 1 Gaucher disease, as well as in an infant with the type 2 form. These findings demonstrate the clinical and molecular genetic heterogeneities of Gaucher disease, the presence of unknown Gaucher allele(s) in most (60%) of the patients surveyed, and the occasional inexplicable lack of phenotype-genotype correlation among some patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

Molecular analysis of gaucher disease: Screening of patients in the Montreal/Quebec region

Gaucher disease, the most prevalent lysosomal storage disease, is an autosomal recessive sphingolipidosis resulting from deficient glucocerebrosidase activity. Genomic DNA of the structural gene of glucocerebrosidase from normal individuals and fifteen unrelated patients with the three clinical forms of Gaucher disease from the Montreal/Quebec region were amplified by the polymerase chain reaction technique. Allele-specific oli-gonucleotide dot blot hybridization and restriction fragment length polymorphism were used to screen for five of the mutations [mutations 120, 370, 415, 444 (Nci), and 463] in exons 5,9, and 10 of glucocerebrosidase gene. It was noted that all of the patients had at least one of the known mutant alleles. However, 9 patients (9/15 = 60%) had an unknown allele. Mutation 370 in exon 9 was present in the heteroallelic form in eight out of the nine patients with type 1 Gaucher disease, but was present in none of the six patients with type 2 or type 3 Gaucher disease. The Nci mutation in exon 10 was present in the heteroallelic form in three patients with type 1 Gaucher disease and in either the heteroallelic or homoallelic form in all of the six patients with type 2 or type 3 Gaucher disease. The 415/Nci mutations were found in a mildly affected 29-year-old patient with type 1 Gaucher disease, as well as in an infant with the type 2 form. These findings demonstrate the clinical and molecular genetic heterogeneities of Gaucher disease, the presence of unknown Gaucher allele(s) in most (60%) of the patients surveyed, and the occasional inexplicable lack of phenotype-genotype correlation among some patients. It also suggests that other genetic factor(s) may be implicated in determining the phenotypic expression of Gaucher disease.     

A cross-sectional,mono-centric pilot study of insulin resistance in enzyme replacement therapy patients with Gaucher type I without overweight

Insulin resistance have been demonstrated in untreated patients with Gaucher type I disease. It was implied in overweight enzyme replacement therapy (ERT) treated patients with Gaucher type I disease. In present study we investigate whether insulin resistance is presented in fourteen ERT treated patients with Gaucher type I disease and without overweight in comparison to normal subjects. This work illustrates the presence of insulin resistance in non-overweight ERT treated patients with Gaucher type I disease.     

Gaucher disease associated with parkinsonism: four further case reports

Type 1 Gaucher disease is considered the non-neuronopathic form of this autosomal recessively inherited lysosomal storage disease. We report the simultaneous occurrence of Gaucher disease with parkinsonian in four adult patients. The patients had a relatively early onset of parkinsonian manifestations, and their disease was rapidly progressive and refractory to therapy. Each had a different Gaucher genotype, although four alleles carried the common N370S mutation. No mutations were identified in the genes for parkin or alpha-synuclein. The concurrence of these two phenotypes, both in this series of patients and in others in the literature, suggests a shared pathway, modifier, or other genetic etiology.     

The role of saposin C in Gaucher disease

Saposin C is one of four homologous proteins derived from sequential cleavage of the saposin precursor protein, prosaposin. It is an essential activator for glucocerebrosidase, the enzyme deficient in Gaucher disease. Gaucher disease is a rare autosomal recessive lysosomal storage disorder caused by mutations in the GBA gene that exhibits vast phenotypic heterogeneity, despite its designation as a "simple" Mendelian disorder. The observed phenotypic variability has led to a search for disease modifiers that can alter the Gaucher phenotype. The PSAP gene encoding saposin C is a prime candidate modifier for Gaucher disease. In humans, saposin C deficiency due to mutations in PSAP results in a Gaucher-like phenotype, despite normal in vitro glucocerebrosidase activity. Saposin C deficiency has also been shown to modify phenotype in one mouse model of Gaucher disease. The role of saposin C as an activator required for normal glucocerebrosidase function, and the consequences of saposin C deficiency are described, and are being explored as potential modifying factors in patients with Gaucher disease.     

Synthetic substrate ß-glucosidase activity in leukocytes: A reproducible method for the identification of patients and carriers of Gaucher''s disease

A method is described for the identification of patients and carriers of Gaucher's disease, using leukocytes from a small volume of blood. The fluorogenic substrate, 4-methylumbelliferyl-beta-D-glucopyranoside, was assayed in the presence of pure sodium taurocholate (2.5 mg/ml) and Triton X-100 (2.0 mg/ml). Some commercial brands of pure sodium taurocholate were satisfactory for this purpose. The pH optimum for controls, Gaucher disease carriers and Gaucher disease patients was 5.4 using citrate-phosphate buffer. Although leukocytes prepared from only a small amount of blood (2-8 ml) are required, there is sufficient quantity for measuring other lysosomal enzymes as controls. Using this method, 12 patients with all types of Gaucher's disease and 12 obligate heterozygotes were identified. Carrier status was predicted in six other family members and ruled out in six others. Eight unaffected people married to Gaucher carriers or Gaucher patients were predicted to be non-carriers of Gaucher's disease, thereby ruling out children affected with Gaucher's disease in that mating.     

Skin ultrastructural findings in type 2 Gaucher disease: diagnostic implications

Background

Type 2 Gaucher disease is a rare and progressive subtype of this lysosomal storage disorder, marked by rapid, early-onset neurodegeneration. Distinguishing type 2 from types 1 and 3 Gaucher disease has remained challenging, due to the lack of a clear correlation between phenotype and enzymatic activity or genotype. β-glucocerebrosidase, the enzyme deficient in Gaucher disease, also has an essential role in maintaining epidermal permeability function, by regulating the ratio of ceramides to glucosylceramides in the stratum corneum of the skin.

Objectives

To further assess the diagnostic utility of epidermal evaluations in distinguishing patients with type 2 Gaucher disease in an expanded cohort.

Study design

Epidermal samples were evaluated from twenty children with type 2, three patients with type 3 Gaucher disease and two adults with type 1 Gaucher disease with different clinical manifestations and genotypes. Electron microscopy on ruthenium tetroxide post-fixed tissue was performed.

Results

Compared to controls and subjects with type 1 and type 3 Gaucher disease, only patients with type 2 Gaucher disease displayed characteristic electron dense, non-lamellar clefts and immature-lamellar membranes.

Conclusion

The appearance of characteristic alterations in epidermal ultrastructure provides an early and specific diagnostic tool to help in distinguishing type 2 from the other types of Gaucher disease.     

Incidence of thrombophilia in patients with Gaucher disease

An inherited risk for thrombosis, including mutant thermolabile variant of methylenetetrahydrofolate reductase (MTHFR), factor V Leiden, or prothrombin may be the co-factor(s) for avascular necrosis (AVN) in patients with sickle cell disease. Similarly, heterozygosity for factor V Leiden is sufficient to explain the increased blood viscosity observed in children with Legg-Calve-Perthes disease who develop AVN. Because there are no laboratory tests or clinical markers that are helpful in predicting which patients with Gaucher disease may develop AVN, the current study was undertaken to ascertain if there exists an inherited predilection to hypercoagulability in patients with Gaucher disease and AVN. Analysis was performed on genomic DNA extracted from 56 adult patients with type I Gaucher disease. In this cohort of Ashkenazi Jewish patients, the frequency of mutations in the MTHFR, prothrombin, and factor V Leiden genes was found to be low, as was the presence of anticardiolipin antibodies; and none was correlated with increased incidence of AVN. Splenectomy, that may be a predisposing factor to AVN in patients with Gaucher disease, was factored out. Hence the presence of any of the above thrombophilic factors, and which by extension may be risk factors for AVN in other diseases, are not more common in patients with Gaucher disease who develop AVN. Studies in larger cohorts and possibly inclusion of additional factors may be needed to ascertain whether a correlation exists.     

Gaucher disease associated with a unique Kphl restriction site: identification of the amino-acid substitution

In an earlier survey of the glucocerebrosidase locus using 20 restriction enzymes and a 1039 bp probe we found that 1 of 9 Gaucher disease patients had a unique pattern with Kpn I, a pattern that was not observed in any other Gaucher patient or in 31 controls. We have now localized the mutation in this patient to a T → A transversion in nucleotide 764 of the cDNA occurring on one of the two glucocerebrosidase alleles. The presumed abnormality in the other allele has not been identified. The deduced amino-acid change in the allele with the mutation at nucleotide 764 is a relatively drastic alteration of amino acid 255 from phenylalanine to tyrosine. The genomic DNAs of 31 other Gaucher disease patients (representing 62 Gaucher disease alleles) were examined for this mutation using the polymerase chain reaction. None were found to have this abnormality.     

Gaucher disease due to saposin C deficiency, previously described as non-neuronopathic form--no positive effects after 2-years of miglustat therapy

Gaucher disease occurs mainly as a result of a deficiency of the lysosomal enzyme beta-glucocerebrosidase activity. A rare variant form of Gaucher disease is known in which saposin C required for glucosylceramide degradation is deficient. In an earlier paper we described the first cases of two siblings with the non-neuronopathic form of Gaucher disease caused by saposin C deficiency [Tylki-Szymańska et al., 2007 [1]]. In this article, we present a follow up of clinical and biochemical findings in one patient who has been treated with miglustat for two years. We observed that administration of miglustat failed to exert any favorable effect on the clinical condition, haematological parameters and glucosylceramide level in the serum. In two individuals (described in this article) very slow deterioration of the peripheral and central nervous systems was observed.     

Upregulation of proinflammatory cytokines in the fetal brain of the Gaucher mouse

Gaucher disease is caused by a deficiency of glucocerebrosidase. Patients with Gaucher disease are divided into three major phenotypes: chronic nonneuronopathic, acute neuronopathic, and chronic neuronopathic, based on symptoms of the nervous system, the severity of symptoms, and the age of disease onset. The characteristics of patients with acute neuronopathic- and chronic neuronopathic-type Gaucher disease include oculomotor abnormalities, bulbar signs, limb rigidity, seizures and occasional choreoathetoid movements, and neuronal loss. However, the mechanisms leading to the neurodegeneration of this disorder remain unknown. To investigate brain dysfunction in Gaucher disease, we studied the possible role of inflammation in neurodegeneration during development of Gaucher disease in a mouse model. Elevated levels of the proinflammatory cytokines, IL-1alpha, IL-1beta, IL-6, and TNF-alpha, were detected in the fetal brains of Gaucher mice. Moreover, the levels of secreted nitric oxide and reactive oxygen species in the brains of Gaucher mice were higher than in wild-type mice. Thus, accumulated glucocerebroside or glucosylsphingosine, caused by glucocerebrosidase deficiency, may mediate brain inflammation in the Gaucher mouse via the elevation of proinflammatory cytokines, nitric oxide, and reactive oxygen species.     

White vitreous opacities in five patients with Gaucher disease type 3

Fundal abnormalities, including preretinal and retinal changes, are a rare finding in patients with the autosomal recessive lysosomal storage disorder Gaucher disease, most often described in patients with the chronic neuronopathic form (type 3). We evaluated whether these ophthalmological findings correlated with other manifestations of type 3 Gaucher disease. Reviewing the records of 40 patients with type 3 Gaucher disease, we identified five with white vitreous opacities and reviewed their clinical course in depth. Each of the patients described decreased visual acuity and “floaters” obstructing their vision. The development and/or progression of these fluffy‐appearing white opacities in each patient were tracked longitudinally in the context of their neurological and other clinical findings. It was noted that all five patients shared genotype p.L483P/p.L483P (L444P/L444P) and had significant neurological, oculomotor and bone involvement and two had undergone splenectomy. Enzyme replacement therapy with recombinant glucocerebrosidase did not prevent the development or progression of these ocular opacities. Since preretinal findings, in addition to other neuro‐ophthalmological findings, can be a feature of Gaucher disease, it is recommended that patients be monitored by regular eye examinations.     

Molecular screening of Japanese patients with gaucher disease: Phenotypic variability in the same genotypes

Gaucher disease is the most prevalent sphingolipidosis, characterized by genetic deficiency of lysosomal hydrolase glucocerebrosidase, and is inherited in an autosomal recessive manner. To characterize the molecular basis of Gaucher disease in Japan, we analyzed for the presence of the two known mutations (1448C and 754A) in the glucocerebrosidase gene of 15 patients (14 families) with Gaucher disease by selective amplification and restriction endonuclease analysis. We found that the 1448C and 754A mutations occurred in all three clinical subtypes of Japanese Gaucher disease patients. The 1448C mutation was found on 12 (40%) out of 30 chromosomes (44% allele frequency in nonneuronopathic form, and 33% in neuronopathic forms), while homozygosity for this mutation was only found in two nonneuronopathic patients (age of 1 year 6 months and 7 years). We detected the 754A mutation on 6 (20%) out of 30 chromosomes. No patient was homozygous for 754A mutation. Furthermore, we identified four patients who were compound hetrozygote for 754A and 1448C. One of these was a type 3 Gaucher patient, but the other three patients were free from central nervous system manifestations at the time of observation. These results indicate that phenotypic presentation of Gaucher disease including the presence of nervous manifestation, progression, and severity of disease, may be affected by other genetic, environmental, or developmental factors, as well as the glucocerebrosidase genotype. © 1993 Wiley-Liss, Inc.