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E Sidransky

Publications and source records attributed to E Sidransky.

At least 55 records · Page 3Linked to original sources
PubMed1997

Prenatal lethality of a homozygous null mutation in the human glucocerebrosidase gene.

The complete spectrum of clinical phenotypes resulting from glucocerebrosidase deficiency continues to evolve. While most patients with Gaucher disease have residual glucocerebrosidase activity, we describe a fetus with severe prenatal lethal type 2 (acute neuronopathic) Gaucher disease lacking glucocerebrosidase activity. This 22-week fetus was the result of a first cousin marriage and had hydrops, external abnormalities, hepatosplenomegaly, and Gaucher cells in several organs. Fetal fibroblast DNA was screened for common Gaucher mutations, none of which was detected. Southern blot analysis using the restriction enzymes SstII and SspI ruled out a fusion gene, deletion, or duplication of either allele, and quantitative studies of SspI digested genomic DNA indicated that both alleles were present. Northern blot analysis of total RNA from fetal fibroblasts demonstrated no detectable transcription, although RT-PCR successfully amplified several exons, suggesting the presence of a very unstable mRNA. Direct PCR sequencing of all exons demonstrated a homozygous frameshift mutation (deletion of a C) on codon 139 in exon 5, thereby introducing a premature termination codon in exon 6. The absence of glucocerebrosidase protein was confirmed by Western analysis. This unique case confirms the essential role of glucocerebrosidase in human development and, like the null allele Gaucher mouse, demonstrates the lethality of a homozygous null mutation. The presence of this novel mutation and the resulting unstable mRNA accounts for the severity of the phenotype observed in this fetus, and contributes to the understanding of genotype/phenotype correlation in Gaucher disease.

Blotting, Southern↗
PubMed1997

Gaucher's disease: the best laid schemes of mice and men.

The creation of animal models of Gaucher's disease, the inherited deficiency of the enzyme glucocerebrosidase, has led to new clinical insights and to a new appreciation of the complexity of the glucocerebrosidase gene locus. Murine embryonic stem cells with targeted modifications in the glucocerebrosidase gene were used to generate mouse models of Gaucher's disease, the first having a null glucocerebrosidase allele. The resulting knockout mice have no glucocerebrosidase activity and die within 12 hours of birth. Ultrastructural studies of liver, spleen, brain and bone marrow demonstrate the characteristic storage material seen in Gaucher patients. In the nervous system, storage of lipid increased in a rostral-caudal distribution. Analysis of skin from the knockout mice revealed histological, ultrastructural and biochemical abnormalities. The null allele Gaucher mice are analogous to neonates with Type 2 Gaucher's disease who present with hydrops foetalis and/or congenital ichthyosis. Moreover, the epidermal changes seen in Type 2 mice are also found in Type 2 patients and may provide a means to presymptomatically discriminate Type 2 from Type 1 and 3 Gaucher's disease. Another targeted modification in the murine glucocerebrosidase gene locus led to the discovery of a contiguous gene, metaxin. Closer analysis of the glucocerebrosidase gene locus, including sequencing of 75 kb of genomic DNA, reveals that this is a gene-rich region coding for seven genes and two pseudogenes. Further study of these closely arrayed genes may contribute to our understanding of the clinical variation encountered among patients with Gaucher's disease.

Animals↗
PubMed1997

Identification of three additional genes contiguous to the glucocerebrosidase locus on chromosome 1q21: implications for Gaucher disease.

Gaucher disease results from the deficiency of the lysosomal enzyme glucocerebrosidase (EC 3.2.1.45). Although the functional gene for glucocerebrosidase (GBA) and its pseudogene (psGBA), located in close proximity on chromosome 1q21, have been studied extensively, the flanking sequence has not been well characterized. The recent identification of human metaxin (MTX) immediately downstream of psGBA prompted a closer analysis of the sequence of the entire region surrounding the GBA gene. We now report the genomic DNA sequence and organization of a 75-kb region around GBA, including the duplicated region containing GBA and MTX. The origin and endpoints of the duplication leading to the pseudogenes for GBA and MTX are now clearly established. We also have identified three new genes within the 32 kb of sequence upstream to GBA, all of which are transcribed in the same direction as GBA. Of these three genes, the gene most distal to GBA is a protein kinase (clk2). The second gene, propin1, has a 1.5-kb cDNA and shares homology to a rat secretory carrier membrane protein 37 (SCAMP37). Finally, cote1, a gene of unknown function lies most proximal to GBA. The possible contributions of these closely arrayed genes to the more atypical presentations of Gaucher disease is now under investigation.

Carrier Proteins↗
PubMed1996

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 recommended that laboratories using PCR-based screening techniques involving primers in this region initially determine whether this 55-bp sequence is present.

Alleles↗
PubMed1996

The clinical, molecular, and pathological characterisation of a family with two cases of lethal perinatal type 2 Gaucher disease.

It has recently been emphasised that a subset of patients with type 2 Gaucher disease die in the neonatal period. This report describes an Afghani family with two conceptuses having severe, prenatally detected Gaucher disease. Mutational analysis showed that the family carried a known complex allele which included mutations at amino acids L444P, A456P, and V460V. Although glucocerebrosidase RNA was present, an affected fetus had virtually no glucocerebrosidase cross reactive material on western analyses. The severe clinical course and pathology observed in these patients resemble that of the null allele Gaucher mouse, and suggest that the absence of glucocerebrosidase activity results in early death.

Afghanistan↗
PubMed1996

Epidermal abnormalities may distinguish type 2 from type 1 and type 3 of Gaucher disease.

A major clinical challenge in Gaucher disease is the early and presymptomatic discrimination of type 2 (acute neuronopathic) from milder type 1 and type 3 Gaucher patients to enable appropriate management and counseling. Although most patients with Gaucher disease do not have skin abnormalities, a subset of patients with severe type 2 Gaucher disease display ichthyosiform skin. Analogous findings occur in the skin of type 2 (null allele) Gaucher mice. Ultrastructural and functional studies of epidermis from these mice reveal that glucocerebrosidase is required to generate functionally competent membranes for normal epidermal barrier function. We have extended our studies by examining the epidermal lipid content and ultrastructure in all three types of Gaucher patients. Only the type 2 Gaucher patients, some of whom had clinical ichthyosis, demonstrated an increased ratio of epidermal glucosylceramide to ceramide as well as extensive ultrastructural abnormalities, including the persistence of incompletely processed lamellar body-derived contents throughout the stratum corneum interstices. These epidermal alterations may provide a means for early differentiation of type 2 Gaucher disease.

Animals↗
PubMed1995

Congenital ichthyosis preceding neurologic symptoms in two sibs with type 2 Gaucher disease.

We describe 2 sibs who presented with ichthyotic skin at birth and subsequently developed neurologic manifestations of type 2 Gaucher disease. Type 2 Gaucher patients with and without ichthyosis manifest ultrastructural and biochemical abnormalities in the epidermis. The 2 patients described here clearly demonstrate that epidermal involvement in type 2 Gaucher disease may precede neurologic symptoms and substantiate the prognostic significance of early skin abnormalities in Gaucher patients. Gaucher disease should be considered in the differential diagnosis of congenital ichthyosis, even if the scaling resolves spontaneously.

Amniocentesis↗
PubMed1995

Diagnosing Gaucher disease. Early recognition, implications for treatment, and genetic counseling.

The diagnosis of Gaucher disease, the inherited deficiency of glucocerebrosidase and the most common inherited disorder of Ashkenazi Jews, can often be missed by clinicians. Medical records from patients with Gaucher disease were reviewed, revealing a wide range of initial misdiagnoses and the frequent use of unnecessary invasive diagnostic procedures. The diagnosis of Gaucher disease is readily established by enzymatic or DNA analyses in conjunction with a thorough history and physical examination. Consequently, greater awareness of the symptoms encountered in these patients could alleviate unnecessary anxiety, testing, and confusion. A definitive diagnosis of Gaucher disease has important implications for genetic counseling and treatment.

Adolescent↗
PubMed1994

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.

Adolescent↗
PubMed1994

Consequences of beta-glucocerebrosidase deficiency in epidermis. Ultrastructure and permeability barrier alterations in Gaucher disease.

Hydrolysis of glucosylceramide by beta-glucocerebrosidase results in ceramide, a critical component of the intercellular lamellae that mediate the epidermal permeability barrier. A subset of type 2 Gaucher patients displays ichthyosiform skin abnormalities, as do transgenic Gaucher mice homozygous for a null allele. To investigate the relationship between glucocerebrosidase deficiency and epidermal permeability barrier function, we compared the stratum corneum (SC) ultrastructure, lipid content, and barrier function of Gaucher mice to carrier and normal mice, and to hairless mice treated topically with bromoconduritol B epoxide (BrCBE), an irreversible inhibitor of glucocerebrosidase. Both Gaucher mice and BrCBE-treated mice revealed abnormal, incompletely processed, lamellar body-derived sheets throughout the SC interstices, while transgenic carrier mice displayed normal bilayers. The SC of a severely affected type 2 Gaucher's disease infant revealed similarly abnormal ultrastructure. Furthermore, the Gaucher mice demonstrated markedly elevated transepidermal water loss (4.2 +/- 0.6 vs < 0.10 g/m2 per h). The electron-dense tracer, colloidal lanthanum, percolated between the incompletely processed lamellar body-derived sheets in the SC interstices of Gaucher mice only, demonstrating altered permeability barrier function. Gaucher and BrCBE-treated mice showed < 1% and < 5% of normal epidermal glucocerebrosidase activity, respectively, and the epidermis/SC of Gaucher mice demonstrated elevated glucosylceramide (5- to 10-fold), with diminished ceramide content. Thus, the skin changes observed in Gaucher mice and infants may result from the formation of incompetent intercellular lamellar bilayers due to a decreased hydrolysis of glucosylceramide to ceramide. Glucocerebrosidase therefore appears necessary for the generation of membranes of sufficient functional competence for epidermal barrier function.

Animals↗