Identification of Gaucher disease carriers: glucocerebrosidase antigen and DNA analysis

Detection of Portuguese carriers for Gaucher disease with urine samples as a source of enzyme was carried out using an immunological procedure employing an anti-glucocerebrosidase monoclonal antibody and by DNA analysis for the presence of the two glucocerebrosidase mutations most frequently found in Portuguese Gaucher patients. Patients, obligate and putative carriers, and individuals unrelated to patients were analyzed. It was found that the vast majority of carriers for the two tested mutations (N370S and L444P), as well as obligate carriers for as yet unidentified mutations, could be distinguished from control subjects with this relatively easy and economic immunological procedure. Furthermore, results obtained for control subjects suggested a high frequency of carriers for the N370S mutation in the Portuguese population. It is concluded that this procedure may be useful in mass screening for carrier detection prior to DNA analysis, particularly in the study of non-Ashkenazi populations in which a significant number of mutations associated with Gaucher disease remain unidentified.

Gaucher disease mutations in non-Jewish patients

The DNA from 64 non-Jewish patients with Gaucher disease was examined for 29 different glucocerebrosidase mutations that are known to cause the disease. The most common was mutation 1448C and the second most common 1226G. Twenty of the mutations remained unidentified. These results were compared to those obtained from 122 Jewish patients, in whom the most common mutations were 1226G and 84GG. Among the non-Jewish patients 15.6% of the mutations remained unidentified, while among the Jewish patients only 1.2% remained unidentified, and even screening for the five most common mutations identified all but 2.9% of the Jewish mutations. The greater diversity of mutations among the non-Jewish patients has important implications with respect to DNA-based screening, diagnosis and counselling.

Synthesis and use of novel fluorescent glycosphingolipids for estimating beta-glucosidase activity in vitro in the absence of detergents and subtyping Gaucher disease variants following administration into intact cells

Two novel fluorescent glycolipids, LRO-glucosylceramide (LRO-GC) and LRO-trihexosylceramide (LRO-THC) were synthesized and utilized for estimating activities of the lysosomal, acid beta-glucosidase in cell extracts and intact skin fibroblasts, derived from normal individuals and patients with Gaucher disease subtypes. The uniqueness of the glycolipids is the fact that a fluorescent probe (lissamine rhodamine) is linked in a sulfonylamide linkage to the sphingosyl residue of the sphingolipid. Thus, the product of enzymatic hydrolysis, lissamine rhodamine sulfonylamido sphingosine (LRO-ceramide) cannot be further hydrolyzed and remains a metabolic end product. A unique property of LRO-GC as a substrate for the lysosomal, acid beta-glucosidase in vitro was the observation that enzymatic hydrolysis occurs in the absence of detergents and that hydrolytic rates are, in fact, reduced in the presence of Triton X-100 and/or sodium taurocholate. Also, both glycolipids penetrated the membrane of intact fibroblasts in the absence of serum and were hydrolyzed in lysosomes of the intact cells. The rates of intracellular hydrolysis decreased with the severity of the Gaucher disease subtypes. Using LRO-THC as substrate, the intracellular ratio of LRO-ceramide to LRO-glucosylceramide was an indicator for the specific GD-subtype.

Adult-type Gaucher disease in children: genetics, clinical features and enzyme replacement therapy

Clinical manifestations of type 1 (Adult) Gaucher disease usually start in childhood. However, most of the previously published data describe the features of this disorder in adults. We present the clinical and genetic characteristics of 34 children and adolescents with type 1 Gaucher disease evaluated in our clinic during the past two years. Patients were aged 2-18 years; 18 were boys and 16 girls. The majority presented before the age of 10. Growth retardation appeared as a prominent feature, with 26% in or below the third percentile in weight, and 30% so in height, especially in the youngest age group (2-5 years). Anaemia and thrombocytopenia occurred in 80% and 60% of the children, respectively. Hepatosplenomegaly was noted in all the children; only 3 were splenectomized. Skeletal involvement was evident on X-rays in 90% of the patients, but only 50% complained of bone pains. Three patients had severe bone disease, with avascular necrosis of the hip joint. Mutation analysis at the DNA level revealed the 1226/1226 genotype in 12 (35%) patients and 1226/84GG in 13 (38%). Correlation was found between the genotypes and the severity of the disease, including growth retardation. A positive response was documented in all 9 patients who completed 12 months of the recently-introduced enzyme replacement therapy for Gaucher disease.

[Molecular diagnosis and gene therapy for Gaucher disease]

Gaucher disease is the most prevalent lysosomal storage disease. It is caused by deficient activity of a lysosomal enzyme known as glucocerebrosidase, also called glucosylceramidase, resulting from mutations in the gene encoding the enzyme. The numerous mutations in glucocerebrosidase gene from patients were reported and the correlation of phenotype and genotype were studied. However, a given genotype cannot be uniquely correlated with a specific phenotype. In the therapeutic point of view, two successful treatment were developed based on the correction of the enzyme deficiency in macrophages. These are bone marrow transplantation and enzyme infusion therapy. Although patients have responded to these two therapies, inherent problems limit their application. Thus, these problems makes Gaucher disease an excellent candidate for therapy based on gene transfer to hematopoietic cells. We succeeded in efficient transduction and sustained high expression of glucocerebrosidase gene in mouse hematopoietic stem cells and macrophages from long term reconstituted mice. The results of our study strengthen the rationale for gene therapy as a treatment for Gaucher disease.

Enzyme replacement therapy of infantile Gaucher disease

We report our experience from enzyme infusion therapy in a girl with infantile (type 2) Gaucher disease. When treatment was started at 5.5 months of age, she already had severe neurological symptoms. After three months of treatment, the hematological parameters and blood glucosylceramide levels were normalized. The spleen and liver sizes were reduced and the neurological deterioration seemed to have stopped. There was, however, no improvement of her existing neurological symptoms. Her lung function deteriorated because of constant aspirations. Enzyme treatment was stopped after seven months. We cannot recommend enzyme substitution therapy when severe neurological signs have already emerged.

Gaucher disease as a paradigm of current issues regarding single gene mutations of humans

Gaucher disease is a glycolytic storage disease caused by a deficiency in activity of the catabolic enzyme glucocerebrosidase. Over 35 different mutations have been documented, including missense and nonsense point mutations, splicing mutations, deletions and insertions, a fusion gene, and examples of gene conversion. Gaucher disease is most common in the Ashkenazi Jewish population, in which just five of the mutations in this population account for 98% of the disease-producing alleles. Each of these mutations is found in the context of a single haplotype, a finding consistent with a single origin of each mutation. Although it is clear that these mutations provide a selective advantage in the Jewish population and thus constitute a balanced polymorphism, the nature of the advantage is unknown. Gaucher disease can be treated symptomatically, by administration of the missing enzyme, by allogeneic bone marrow transplantation, and potentially by gene transfer into hematopoietic stem cells. Increasing understanding of this disease has, as in other genetic disorders, created a host of social and ethical dilemmas regarding matters such as the cost of treatment for rare diseases and the advantages and disadvantages of population-targeted genetic screening.

1448C mutation linked to the Pv1.1- genotype in Italian patients with Gaucher disease

Gaucher disease is the most common of the glycolipid storage diseases and is caused by an inherited deficiency of the enzyme glucocerebrosidase. It is a very heterogeneous disease and presents early and late onset forms which may or may not be associated with a neurological disease. Several point mutations of the glucocerebrosidase gene have been reported to cause this disease. This is the first report of the mutations causing GD in Italy. In this study of ten patients of non-Jewish origin, two mutations (1226G and 1448C) accounted for 19 of 20 disease alleles. In these patients a gene frequency of 33% for the 1226G mutation and 57.8% for the 1448C mutation was found. The patients homozygous for the 1448C mutation were also homozygous for the Pv1.1- genotype (polymorphic Pvu II site present at nt. 3931). This is in contrast with previous reports linking 1448C mutation to the Pv1.1+ genotype. Two out of the three 1448C homozygous patients are currently free of any evident neurological symptoms. These patients have been undergoing enzyme-replacement therapy for the last one year and have a Pv1.1-/1448C glucocerebrosidase haplotype. Both these factors appear to be associated with a late development of neuronopathic disease.

Phenotype/genotype correlations in Gaucher disease type I: clinical and therapeutic implications

Gaucher disease is the most frequent lysosomal storage disease and the most prevalent genetic disease among Ashkenazi Jews. Gaucher disease type 1 is characterized by marked variability of the phenotype and by the absence of neuronopathic involvement. To test the hypothesis that this phenotypic variability was due to genetic compounds of several different mutant alleles, 161 symptomatic patients with Gaucher disease type 1 (> 90% Ashkenazi Jewish) were analyzed for clinical involvement, and their genotypes were determined. Qualitative and quantitative measures of disease involvement included age at onset of the disease manifestations, hepatic and splenic volumes, age at splenectomy, and severity of bony disease. Highly statistically significant differences (P < .005) were found in each clinical parameter in patients with the N370S/N370S genotype compared with those patients with the N370S/84GG, N370S/L444P, and N370S/? genotypes. The symptomatic N370S homozygotes had onset of their disease two to three decades later than patients with the other genotypes. In addition, patients with the latter genotypes have much more severely involved livers, spleens, and bones and had a higher incidence of splenectomy at an earlier age. These predictive genotype analyses provide the basis for genetic care delivery and therapeutic recommendations in patients affected with Gaucher disease type 1.

Gaucher disease: a heterogeneous clinical complex for which effective enzyme replacement has come of age

Gaucher disease, the most common form of lysosomal storage disease, is the result of autosomal recessive inheritance of a lysosomal enzyme glucocerebrosidase deficiency, which produces defective hydrolysis of glucosylceramide that accumulates in reticuloendothelial (tissue macrophage) cells. The current review focuses on Type 1 (the nonneuronopathic) or adult Gaucher disease and defines the clinical manifestations (splenomegaly, hepatomegaly, bony lesions, and clinical metabolic dysfunction) in relationship to the known enzymatic defect. The clinical diversity and variability in symptoms and signs, the age at onset of the clinical manifestations and their rate of progression, and the heterogeneity of the organs involved are reviewed. Extensive delineation of the nature of the enzyme defect and the recent molecular characterization of the enzyme mutants has not provided an explantation for the remarkable clinical phenotypic heterogeneity. Enzyme assays now provide an excellent method for diagnosis. Effective enzyme replacement therapy emphasizes the value of early diagnosis and has altered the costs and potential risks of older therapeutic indications for splenectomy or cytokine therapy. Enzyme efficacy raises questions about the specific indications for replacement treatment and the most desirable rate and duration of enzyme delivery.

Gaucher's disease in the United Kingdom: screening non-Jewish patients for the two common mutations

Twenty-six patients with Gaucher's disease diagnosed in the United Kingdom and two obligate carriers, all of non-Jewish origin, were screened for the two common disease causing mutations and two rarer mutations in the glucocerebrosidase gene. These mutations are referred to as N370S, L444P, Ins84G, and 1066 + 1G-->A, respectively. The results showed that out of 54 alleles screened, 26% were N370S, 35% were L444P, and the remaining 39% were rare or undefined. The results also showed a clear correlation between the presence of at least one N370S allele and mild disease.

[Gaucher's disease: study of a family from Friuli]

Gaucher's disease is the most frequent of lysosomal storage diseases. In a family study two affected sisters of a type I patient were identified. Two of them underwent splenectomy, so reaching hematological normalization.

Role of pH in determining the cell-type-specific residual activity of glucocerebrosidase in type 1 Gaucher disease

The properties of control and 370Asn-->Ser glucocerebrosidase, the frequently encountered mutated form of the enzyme in type 1 Gaucher disease, were studied in vitro as well as in situ. The catalytic properties of purified 370Asn-->Ser glucocerebrosidase were highly dependent on the assay conditions. The enzyme was deficient in activity towards substrate and in reactivity with the irreversible inhibitor conduritol B-epoxide (CBE) when activated by the bile salt taurocholate. In the presence of more physiological activators, the lysosomal activator protein saposin C and phosphatidylserine, the 370Asn-->Ser enzyme was near normal in kinetic properties at pH values approximately 5, but not at higher pH. In intact fibroblasts, the enzymic activity of the 370Asn-->Ser glucocerebrosidase and its reactivity with CBE were found to be clearly deficient. However, in intact lymphoblasts from the same patients, the behavior of the mutant enzyme was near normal. The catalytic efficiency of 370Asn-->Ser glucocerebrosidase in situ was also found to be highly pH dependent. When intact lymphoblasts were cultured in the presence of permeant weak bases, which increase the pH of acidic intracellular compartments, the catalytic efficiency of the mutant enzyme, as assessed by its reactivity with CBE, became markedly impaired. Our findings indicate that the intralysosomal pH in the intact cell can be expected to have a critical influence on the activation state of 370Asn-->Ser glucocerebrosidase and its ability to hydrolyse substrate. This phenomenon may partly underly the marked heterogeneity in clinical manifestation of Gaucher disease among patients with this mutated form of glucocerebrosidase.

[Update on Gaucher's disease]

Gaucher's disease is a lipidosis caused by deficiency of the enzyme glucocerebrosidase (glucosylceramidase) with secondary accumulation of glucocerebrosides in macrophage lysosomes. Three clinical forms of the disease have been described with autosomal recessive genetic basis. They are caused by many different mutations in glucocerebrosidase gene which have been recently identified. The infantile (type III) and juvenile (type II) forms involve the central nervous system and are very rare. Type I is a non neuronopathic form and is the most common lysosomal storage disease, reaching an incidence of 1 in 2500 births among Ashkenazi jews. Clinical manifestations include splenomegaly and hypersplenism, while bone and lung involvement are less common. Most patients have a mild course and a normal life expectancy, but some others suffer for heavy bone pain that greatly inhabilitate them. A distinctive storage cell is present in bone marrow, but diagnostic confirmation is based upon leucocytes or fibroblasts enzyme assay. Total or partial splenectomy is the treatment of choice for correcting hematological abnormalities. Allogeneic bone marrow transplantation was successfully employed in some cases, while studies on retroviral-mediated gene transfer are undergoing. Promising clinical results were obtained in last two years by chronic infusion of purified macrophage-targeted glucocerebrosidase enzyme. New experience is required in selecting patients for this expensive regimen and establishing duration of therapy.

Molecular characteristics in Japanese patients with lipidosis: novel mutations in metachromatic leukodystrophy and Gaucher disease

The characterization of mutations in Japanese patients with lipidosis, particularly in metachromatic leukodystrophy (MLD) and Gaucher disease has been studied in detail. Metachromatic leukodystrophy is characterized by an accumulation of sulfatide in nervous tissues and kidney due to a deficiency of arylsulfatase A (ASA). We analyzed the presence of three known mutant arylsulfatase A alleles in Japanese patients with MLD. Among 10 patients of Japanese patients with MLD, we found that allele 445A mutation has moderately high incidence and also homozygosity of this mutation results in the late infantile form. Allele 2381T was not found in Japanese patients. Furthermore, we found novel mutation which is G- to A mutation at the 1070 nucleotide of the ASA gene (designated 1070 A) in Japanese patients with juvenile onset. This mutation results in a amino acid substitution of Gly245 by Arg and found in heterozygote form. Our studies of molecular analysis in 10 Japanese patients with MLD indicate that Japanese MLD patients have unique characteristics of ASA mutations compared with those of Caucasian patients. On the other hand, Gaucher disease is the most prevalent sphingolipidosis, characterized by an accumulation of glucocerebroside in macrophage derived cells due to a deficiency of lysosomal hydrolase glucocerebrosidase. To study the molecular basis of Gaucher disease in Japanese patients, we analyzed the presence of the two known mutations (6433C and 3548A) in the glucocerebrosidase gene of 15 patients with Gaucher disease. We found that the 6433C and 3548A mutations occur in all subtypes of Japanese patients with Gaucher disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Type 1 Gaucher disease: molecular, biochemical, and clinical characterization of patients from northern Portugal

We report the study of 16 catholic type 1 Gaucher disease patients originating from a well-defined region in the north of Portugal where a relatively high incidence is observed. The patients were screened for mutations: 3060G-->A, 5841A-->G, 5976C-->G, and 6433T-->C, which enabled the identification of 27 of the 32 mutated alleles. Four different genotypes were identified, namely 5841G/6433C (n = 6), 5841G/5841G (n = 5), 5841G/? (n = 4), and 6433C/? (n = 1). All but one of the patients carried at least one 5841G mutated allele, making its frequency 62.5%, which is similar to that described for Ashkenazi Jewish patients. The 5841G homozygotes presented an overall milder clinical profile, whereas no clear genotype/phenotype correlation could be established for heterozygous patients. On the basis of residual glucocerebrosidase activity, no distinction could be made between 5841G homozygotes and 5841G/6433C compound heterozygotes. Patients that had at least one 5841G allele (encoding the Ser 370 mutated enzyme) all presented a cell-type-specific residual glucocerebrosidase activity as well as an increased molecular activity when measured in the presence of the physiological activators.

Abnormal neutrophil chemotaxis in Gaucher disease

The tendency towards infection described in Gaucher disease patients has been attributed to their post-splenectomy state. We noticed that certain patients with intact spleen have also suffered from recurrent pyogenic infections, thus an attempt to study their neutrophil function has been made. Nine of 29 patients studied expressed significant decrease in neutrophil chemotaxis directed towards zymosan activated serum or N-formyl-methionyl-leucyl-phenylalanine. Random migration was significantly impaired in five of those nine patients. Adherence of neutrophils to nylon fibres and O2- production were intact. The patients with impaired chemotaxis were significantly afflicted by their disease (early onset of symptoms and severity score index > 10) and most of them had genotypes associated with severe disease (1448/1448 and 1226/84GG). No correlation was found with the spleen status. Three of the patients with impaired chemotaxis, and none of the patients with normal neutrophil function, suffered from recurrent pyogenic infections. It is suggested that the described neutrophil migration impairment may contribute to the tendency towards infection in certain patients with advanced Gaucher disease.

Mutational analysis in a patient with a variant form of Gaucher disease caused by SAP-2 deficiency

It is now clear that the lysosomal hydrolysis of sphingolipids requires both lysosomal enzymes and so-called sphingolipid activator proteins (SAPs). One gene, called prosaposin, codes for a precursor protein that is proteolytically cut into four putative SAPs. These four SAPs, of about 80 amino acids, share some structural features but differ somewhat in their specificity. Domain 3 of prosaposin mRNA contains the coding region for SAP-2, an activator of glucocerebrosidase. While most patients with Gaucher disease store glucosylceramide due to defects in glucocerebrosidase, a few patients store this lipid in the presence of normal enzyme levels. In this paper we describe the identification of a point mutation in domain 3 of a patient who died with this variant form of Gaucher disease. Polymerase chain reaction amplification was performed in the small amount of genomic DNA available using primers generated from the intronic sequence surrounding domain 3. The patient was found to have a T-to-G substitution at position 1144 (counting from the A of ATG initiation codon) in half of the M13 recombinant clones. This changes the codon for cysteine382 to glycine. His father and unaffected brother also had this mutation, but his mother did not. She was found to have half of the normal amount of mRNA for prosaposin in her cultured skin fibroblasts. Therefore, this child inherited a point mutation in domain 3 from his father and a deficiency of all four SAPs coded for by prosaposin from his mother.

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.

Gaucher disease: gene frequencies in the Ashkenazi Jewish population

DNA from over 2,000 Ashkenazi Jewish subjects has been examined for the four most common Jewish Gaucher disease mutations, which collectively account for about 96% of the disease-producing alleles in Jewish patients. This population survey has made possible the estimation of gene frequencies for these alleles. Eighty-seven of 1,528 individuals were heterozygous for the 1226G (N370S) mutation, and four presumably well persons were homozygous for this mutation. The gene frequency for the 1226G allele was calculated to be .0311, and when these data were pooled with those obtained previously from another 593 Jewish subjects, a gene frequency of .032 with a standard error of .004 was found. Among 2,305 normal subjects, 10 were found to be heterozygous for the 84GG allele, giving a gene frequency of .00217 with a standard error of .00096. No examples of the IVS2(+1) mutation were found among 1,256 samples screened, and no 1448C (L444P) mutations were found among 1,528 samples examined. Examination of the distribution of Gaucher disease gene frequencies in the general population shows that the ratio of 1226G mutations to 84GG mutations is higher than that in the patient population. This is presumed to be due to the fact that homozygotes for the 1226G mutation often have late-onset disease or no significant clinical manifestations at all. To bring the gene frequency in the patient population into conformity with the gene frequency in the general population, nearly two-thirds of persons with a Gaucher disease genotype would be missing from the patient population, presumably because their clinical manifestations were very mild.

Identification of six new Gaucher disease mutations

The four most common mutations account for 97% of the Gaucher disease-producing alleles in Jewish patients and 75% of the alleles in non-Jewish patients. Although at least 15 other mutations and some examples of gene conversion and/or fusion genes have been described, a number of mutations remain unidentified. We have now identified six new mutations, a deletion of a C at the 72 position of the cDNA, a 481C-->T mutation (122Pro-->Ser), a 751T-->C (212Tyr-->His), a 1549G-->A (478Gly-->Ser), a 1604G-->A (496Arg-->His), and a 55-bp deletion. All but one of these were found in single families. The 1604A mutation, however, was observed in four unrelated individuals.

Efficient transfer and sustained high expression of the human glucocerebrosidase gene in mice and their functional macrophages following transplantation of bone marrow transduced by a retroviral vector

A recombinant retroviral vector (MFG-GC) was used to study the efficiency of transduction of the human gene encoding glucocerebrosidase (GC; D-glucosyl-N-acylsphingosine glucohydrolase, EC 3.2.1.45), in mouse hematopoietic stem cells and expression in their progeny. Transfer of the GC gene to CFU-S (spleen cell colony-forming units) in primary and secondary recipients was virtually 100%. In mice 4-7 months after transplantation, highly efficient transfer of the human gene to bone marrow cells capable of long-term reconstitution was confirmed by detection of one or two copies per mouse genome in hematopoietic tissues and in cultures of pure macrophages. Expression of the human gene exceeded endogenous activity by several fold in primary and secondary CFU-S, tissues from long-term reconstituted mice, and explanted macrophages cultures. These studies are evidence of the feasibility of efficient transfer of the GC gene to hematopoietic stem cells and expression in their progeny for many months after reconstitution. The results of this study strengthen the rationale for gene therapy as a treatment for Gaucher disease.

Rapid identification of mutations in the glucocerebrosidase gene of Gaucher disease patients by analysis of single-strand conformation polymorphisms

To detect mutations in the glucocerebrosidase gene in Gaucher disease patients, we used the recently described technique of single-strand conformation polymorphism (SSCP) analysis in combination with selective amplification. We analyzed exon 8, 9, 10 and 11 of the glucocerebrosidase gene; these exons were sequentially amplified using the selectively amplified products as templates. We found variant SSCP patterns corresponding to the presence or absence of the 6433C mutation, which was detected by NciI digestion analysis, in exon 10. Furthermore, we detected four variant SSCP patterns in exon 8, 10 and 11. Sequencing analysis consistently revealed four single-base substitutions in the corresponding exons, three novel missense mutations (5409A, 6375G and 6682T) and one silent polymorphism (6594A). These mutations were found only in one patient; therefore, these findings have confirmed the marked genetic heterogeneity of Gaucher disease. SSCP analysis in combination with selective amplification is a rapid and sensitive procedure for the screening of the mutations in the glucocerebrosidase gene of patients with Gaucher disease.

Gaucher disease. Clinical, laboratory, radiologic, and genetic features of 53 patients

We have reviewed our experiences with the clinical, laboratory, radiologic, and genetic features of 53 patients with Gaucher disease. Most were evaluated during early adult life, with a mean age of 33 years. Our patients were evaluated in a referral center, and therefore the data need to be interpreted with caution when applied to the general patient population, which includes a greater proportion of very mild cases. Thirty-nine patients were Ashkenazi Jews, 13 were non-Jewish and 1 was half-Jewish. The most common presenting symptom was bleeding related to splenomegaly and thrombocytopenia. The chronic symptoms, evaluated an average of 20 years after the diagnosis had been established, were mainly skeletal. Splenectomy had been performed in 43% of our patients and there was no evidence that this procedure accelerated the progression of liver and bone involvement. DNA from the patients was examined for 20 different mutations. The association between the 1226G/1226G genotype and a milder clinical course, and between the 1226G/84GG and 1226/1448C genotypes with more severe clinical manifestations, was confirmed. Repeated follow-up examinations in 29 patients revealed that in the majority of the patients, progression of the disease occurs during childhood, adolescence, or early adulthood with a marked tendency for stabilization thereafter. This observation suggests that Gaucher disease in most of the patients is not a relentless progressive disorder but a rather stable disorder during adulthood. The indications for the newly introduced intravenous enzyme replacement therapy as well as of future experimental treatments should be examined in the light of the natural history of the disease.

[A case of adult Gaucher disease]

The authors describe a case of an adult patient having Gaucher's disease, who had hepatosplenomegaly and pancytopenia. The diagnosis was established by the low level of leukocyte beta-glucosidase and by histology of bone marrow, liver and spleen. The patient had no bone pain, but MRI described characteristic lesions of the femur. Serum acid phosphatase was characteristically elevated. The hypersplenism was reduced after splenectomy. The patient has a daughter with central nervous system dysfunction. Her chromosome examination is normal, but she has lower leukocyte beta-glucosidase activity too. She may have a Gaucher's disease of type II, the acute neuropathic form.

Hydrocephalus, corneal opacities, deafness, valvular heart disease, deformed toes and leptomeningeal fibrous thickening in adult siblings: a new syndrome associated with beta-glucocerebrosidase deficiency and a mosaic population of storage cells

We describe three adult siblings with communicating hydrocephalus, corneal opacities, deafness, valvular heart disease, and deformed toes associated with glucosylceramide (glc-cer)-beta-glucosidase deficiency. The common manifestations of Gaucher disease were not evident. Supranuclear gaze palsies characteristic of type 3 were noted from early childhood, although the major signs were undeveloped until early adult life. Autopsy disclosed thickened leptomeninges with perivascular fibrosis, non-rheumatic calcified aortic and mitral stenosis with marked fibrosis, and mild infiltration of Gaucher cells in the reticuloendothelial organs. In contrast to the slight accumulation of glc-cer in the liver and spleen, the activity of glc-cer-beta-glucosidase was markedly decreased in the tissues, as much as in a patient with type 2 Gaucher disease. Common mutations were not found in the glucocerebrosidase gene.

Gaucher disease in the neonate: a distinct Gaucher phenotype is analogous to a mouse model created by targeted disruption of the glucocerebrosidase gene

A group of neonates with Gaucher disease with a particularly devastating clinical course is described. The phenotype of these infants is analogous to that of a Gaucher mouse, which was created by targeted disruption of the mouse glucocerebroside gene. Similar to the homozygous mutant mice with glucocerebrosidase deficiency, these infants present at or shortly after birth, have rapidly progressing fulminant disease, and many have associated ichthyotic skin and/or hydrops fetalis. This transgenetic mouse model of Gaucher disease has helped us to appreciate a distinct Gaucher phenotype. Potentially, as this technology is applied to create other animal models of metabolic diseases, it may enable the recognition of other, as yet unappreciated presentations of inherited disorders.

[Response criteria for enzyme substitution in Gaucher disease]

Recently the intravenous enzyme replacement therapy with modified beta-glucocerebrosidase has become available for patients with M. Gaucher. We report here the considerable improvement of activity and vigor in a 5 year old girl with type 1 M. Gaucher administering 60 IU/kg every two weeks for 6 months. The platelet count increased from 82-96/nl to more than 150/nl and hemoglobin from 10.8 to more than 12 g/dl. Serum acid phosphatase decreased from 14.6 U/l to 5.9. U/l and angiotensin-converting enzyme from 327 to 102 U/l. The estimation of splenic volume by MRT showed a decrease by 40%, while liver size was not reduced within 6 months of therapy. MRT proved to be useful to demonstrate the bone marrow infiltration by Gaucher cells. The enzyme replacement therapy resulted in an objective response. No side effects have been observed so far. The extreme high treatment costs enforce a considerable dose reduction for maintenance therapy.

Gaucher disease: A G+1----A+1 IVS2 splice donor site mutation causing exon 2 skipping in the acid beta-glucosidase mRNA

Gaucher disease is the most frequent lysosomal storage disease and the most prevalent Jewish genetic disease. About 30 identified missense mutations are causal to the defective activity of acid beta-glucosidase in this disease. cDNAs were characterized from a moderately affected 9-year-old Ashkenazi Jewish Gaucher disease type 1 patient whose 80-year-old, enzyme-deficient, 1226G (Asn370----Ser [N370S]) homozygous grandfather was nearly asymptomatic. Sequence analyses revealed four populations of cDNAs with either the 1226G mutation, an exact exon 2 (delta EX2) deletion, a deletion of exon 2 and the first 115 bp of exon 3 (delta EX2-3), or a completely normal sequence. About 50% of the cDNAs were the delta EX2, the delta EX2-3, and the normal cDNAs, in a ratio of 6:3:1. Specific amplification and characterization of exon 2 and 5' and 3' intronic flanking sequences from the structural gene demonstrated clones with either the normal sequence or with a G+1----A+1 transition at the exon 2/intron 2 boundary. This mutation destroyed the splice donor consensus site (U1 binding site) for mRNA processing. This transition also was present at the corresponding exon/intron boundary of the highly homologous pseudogene. This new mutation, termed "IVS2 G+1----A+1," is the first splicing mutation described in Gaucher disease and accounted for about 3.4% of the Gaucher disease alleles in the Ashkenazi Jewish population. The occurrence of this "pseudogene"-type mutation in the structural gene indicates the role of acid beta-glucosidase pseudogene and structural gene rearrangements in the pathogenesis of this disease.

Retroviral-mediated transfer of the human glucocerebrosidase gene into cultured Gaucher bone marrow

Gaucher disease, a lysosomal glycolipid storage disorder, results from the genetic deficiency of an acidic glucosidase, glucocerebrosidase (GC). The beneficial effects of allogeneic bone marrow transplantation (BMT) for Gaucher disease suggest that GC gene transduction and the transplantation of autologous hematopoietic stem cells (gene therapy) may similarly alleviate symptoms. We have constructed a retroviral vector, L-GC, produced by a clone of the amphotropic packaging cell line PA317, which transduces the normal human GC cDNA with high efficiency. Whole-marrow mononuclear cells and CD34-enriched cells from a 4-yr-old female with type 3 Gaucher disease were transduced by the L-GC vector and studied in long-term bone marrow culture (LTBMC). Prestimulation of marrow with IL-3 and IL-6, followed by co-cultivation with vector-producing fibroblasts, produced gene transfer into 40-45% of the hematopoietic progenitor cells. The levels of GC expression in progeny cells (primarily mature myelomonocytic) produced by the LTBMC were quantitatively analyzed by Northern blot, Western blot, and glucocerebrosidase enzyme assay. Normal levels of GC RNA, immunoreactive protein, and enzymatic activity were detected throughout the duration of culture. These studies demonstrate that retroviral vectors can efficiently transfer the GC gene into long-lived hematopoietic progenitor cells from the bone marrow of patients with Gaucher disease and express physiologically relevant levels of GC enzyme activity.

Animal model of Gaucher's disease from targeted disruption of the mouse glucocerebrosidase gene

Gaucher's disease is the most prevalent lysosomal storage disorder in humans and results from an autosomally inherited deficiency of the enzyme glucocerebrosidase (beta-D-glucosyl-N-acylsphingosine glucohydrolase), which is responsible for degrading the sphingolipid glucocerebroside. An animal model for Gaucher's disease would be important for investigating its phenotypic diversity and pathogenesis and for evaluating therapeutic approaches. A naturally occurring canine model has been reported but not propagated. Attempts to mimic the disease in animals by inhibiting glucocerebrosidase have been inadequate. Here we generate an animal model for Gaucher's disease by creating a null allele in embryonic stem cells through gene targeting and using these genetically modified cells to establish a mouse strain carrying the mutation. Mice homozygous for this mutation have less than 4% of normal glucocerebrosidase activity, die within twenty-four hours of birth and store glucocerebroside in lysosomes of cells of the reticuloendothelial system.

Gaucher disease: new molecular approaches to diagnosis and treatment

Gaucher disease is characterized by the accumulation of glucocerebroside, leading to enlargement of the liver and spleen and lesions in the bones. It is caused by an inherited deficiency of the enzyme glucocerebrosidase. Many mutations exist, but four of these account for over 97% of the mutations in Ashkenazi Jews, the population group in which Gaucher disease is the most common. Although there is a strong relation between the mutations and disease manifestations, genetic counseling is made difficult by the fact that within each genotype there is considerable variability in the severity of the disease. Intravenous infusion of glucocerebrosidase is an effective treatment, but the availability of enzyme replacement therapy is limited by its high cost. Marrow transplantation is also effective in treating the disease, but is rarely performed because of the risks involved. In the future gene transfer may become the treatment of choice.

Genetic diagnosis of Gaucher's disease

The inherited disorder Gaucher's disease can be caused by various mutations in the glucocerebrosidase gene. Some mutations may be associated with greater severity, and there is a need for methods of gene analysis that would facilitate screening and diagnosis. We have studied the molecular basis of Gaucher's disease in twelve unrelated patients of diverse ethnic origin by means of the amplification refractory mutation system (ARMS). Primers for the polymerase chain reaction were designed to discriminate between mutant and wild-type alleles of glucocerebrosidase and to allow separation from products of the related pseudogene. The nucleotide 1226 mutation (asparagine 370----serine) and 84GG (an insertional frameshift mutation) were found exclusively in five patients of Ashkenazi Jewish descent (7 and 2 of the 10 disease alleles, respectively). Two point mutations, at nucleotides 1448 (leucine 444----proline) and 1504 (arginine 463----cysteine), were found in 4 and 3 alleles, respectively; they were associated with rapidly progressive disease and neurological involvement in non-Jewish patients. The ARMS procedure for direct detection of common mutations in glucocerebrosidase will facilitate genetic counselling and screening programmes for individuals at risk of Gaucher's disease.

Polymorphisms in the human glucocerebrosidase gene

The two glucocerebrosidase genes from a patient with Gaucher disease were cloned and 8850 bp of each sequenced. Each clone had a single nucleotide change accounting for the clinical glucocerebrosidase deficiency, an A to G transition at cDNA nucleotide 1226 in one clone, and an insertion of a G at cDNA nucleotide 84 in the other clone. Sequence analysis revealed that there were 11 additional differences between the two clones. The clone with the nt 1226 mutation was, as is always the case, Pv1.1- (polymorphic PvuII site present). The 84GG clone was Pv1.1+. Examination of 35 normal subjects and 51 Gaucher disease patients was consistent with the existence of only two major haplotypes. Two additional minor haplotypes were found, one in Africans and one in the white population. These represented additional mutations superimposed on the basic two haplotypes. Two unrelated patients with Gaucher disease seemed to be exceptions in the 5' end of the gene was heterozygous for the + and - haplotypes but the most 3' marker was homozygous. These patients are believed to have a gene deletion on one allele. In addition to these studies, we correct 28 minor errors in the originally published sequence.

Mutations in Jewish patients with Gaucher disease

DNA from 100 unrelated patients, 97 of whom were Jewish and three half-Jewish, was analyzed for 22 mutations known to cause Gaucher disease. All but seven of the alleles were identified as having previously described mutations. Five of the unidentified mutations proved to be a previously undescribed nucleotide substitution in a splice junction (IVS2+1) that causes skipping of exon 2. Thus, only 2 of 197 alleles remained unidentified. Homozygotes for the most common mutation, that a nucleotide (nt) 1226, manifested, on average, the mildest disease and the latest age of onset. The mutation at nt 84 and the newly described IVS2+1 mutation, which do not produce any enzyme, were associated with earlier onset and more severe disease. Five of the mutations were considered to be "public," in the sense that they were found in more than one unrelated individual. Screening for these five mutations permitted detection of 97.5% of all Gaucher alleles in this patient population. Because the mutation at nt 1226 is underrepresented in the patient population and because not all homozygotes come to medical attention, screening the Ashkenazi population using DNA analysis should detect approximately 99% of all heterozygotes.

DNA mutation analysis of Gaucher patients

We evaluated 62 Gaucher patients to determine whether patients with similar phenotypes had the same DNA point mutations. Genomic DNA from these Gaucher patients was screened for the 3 most frequent single-point mutations, occurring in 69% of the 124 patient alleles, and resulting in changes in amino acids 370, 444, and 463. Many different genotypes were observed, at least one of which is present in all 3 types of Gaucher disease. No specific symptom complex could be correlated with a unique genotype. Even the more clinically homogeneous subgroups of Gaucher patients contained several genotypes. This study further emphasizes the need for caution in making clinical predictions on the basis of current genotype analysis, especially since one might not discern a fetus affected with type 2 disease by current DNA studies. The severity of involvement in type 1 disease could also not be predicted. Thus, even limiting our focus to 3 isolated common point mutations, a given genotype cannot be uniquely correlated with a specific prognosis.

Gaucher's disease with mitral and aortic involvement: echocardiographic findings

Cardiac involvement in Gaucher's disease has been reported in only a few patients, mostly adults with pericardial changes. We describe findings in two siblings with Gaucher's disease, aged 15 and 9 years respectively, in whom mitral and aortic valve lesions were evaluated by auscultation and echocardiography. In both cases the mitral and aortic valves were thick and restricted in motion. Continuous Doppler echocardiography revealed significant mitral regurgitation and mitral stenosis. At the aortic valve level there was a systolic pressure gradient. Echocardiographic investigation of patients with suspected cardiac involvement with Gaucher's disease is recommended.

Gaucher patients with oculomotor abnormalities do not have a unique genotype

Sixteen non-Ashkenazic American children with Gaucher disease who demonstrate slowing of the horizontal saccades are described. Attempts to correlate this specific clinical phenotype with a unique genotype were unsuccessful. Focusing on the three most common mutations, at least five different genotypes were present in these patients. Children with this isolated oculomotor abnormality generally had a diffusely slowed background on EEG, but an otherwise normal neurologic examination, and exhibited earlier and more severe systemic manifestations and mortality. This study emphasizes the need for careful sequential neuro-ophthalmologic examinations in Gaucher patients and the need for caution in attempting to make clinical predictions regarding the course of Gaucher disease on the basis of current DNA mutational analysis.

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)

A new glucocerebrosidase-gene missense mutation responsible for neuronopathic Gaucher disease in Japanese patients

We have identified a new T-to-A single-base substitution at nucleotide 3548 (in the genomic sequence) in exon 6 in the glucocerebrosidase gene from a patient with Gaucher disease type 3. This mutation caused a substitution of isoleucine for phenylalanine at amino acid residue 213 (of 497 residues in the mature protein). By in vitro expression study in cultured mammalian cells, this mutation resulted in deficient activity of glucocerebrosidase. By allele-specific oligonucleotide hybridization of selectively PCR-amplified DNA from eight unrelated Japanese Gaucher disease patients, this mutant allele was observed in other neuronopathic Japanese Gaucher disease patients, in moderately frequent occurrence (three of six neuronopathic patients). This observation suggests that this allele was one of severe [corrected] alleles which were related to the development of neurological manifestations of Gaucher disease.