Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0272170 (SDS)
 50,377 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Shwachman-Diamond syndrome (SDS) is caused by mutations in the SBDS gene, most of which are the result of gene conversion events involving its highly homologous pseudogene SBDSP. Here we describe the molecular characterization of the first documented gross deletion in the SBDS gene, in a 4-year-old Portuguese girl with SDS. The clinical diagnosis was based on the presence of hematological symptoms (severe anemia and cyclic neutropenia), pancreatic exocrine insufficiency and skeletal abnormalities. Routine molecular screening revealed heterozygosity for the common splicing mutation c.258+2T>C, and a further step-wise approach led to the detection of a large deletion encompassing exon 3, the endpoints of which were subsequently delineated at the gDNA level. This novel mutation (c.258+374_459+250del), predictably giving rise to an internally deleted polypeptide (p.Ile87_Gln153del), appears to have arisen from an excision event mediated by AluSx elements which are present in introns 2 and 3. Our case illustrates the importance of including gross deletion screening in the SDS diagnostic setting, especially in cases where only one deleterious mutation is detected by routine screening methods. In particular, deletional rearrangements involving exon 3 should be considered, since Alu sequences are known to be an important cause of recurrent mutations.
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PMID:Identification of a novel AluSx-mediated deletion of exon 3 in the SBDS gene in a patient with Shwachman-Diamond syndrome. 1737 17

Prompt and accurate diagnosis is required for optimal treatment and genetic counseling of patients with inherited bone marrow failure syndromes (IBMFS). However, the diverse clinical picture of these syndromes and their rareness is often associated with diagnostic difficulties. Recently, an improved diagnostic approach is possible by the cloning of many of the causative genes. Fanconi anemia (FA) patients belong to at least 12 complementation groups, of which 11 genes have been cloned. An approach combining an induced chromosomal breakage test, detection of FANCD2-L by Western blot analysis, complementation group analysis, and detailed mutation analysis enables unraveling the causative mutation in the majority of patients. With the use of such strategies, genotype/phenotype correlations in FA are evolving. In dyskeratosis congenita mutations in DCK1, TERC, and TERT genes have been identified, but mutations have been found in less than half of these patients. In patients with Shwachman-Diamond syndrome, mutations in the SBDS gene were found in approximately 90% of patients. In Diamond-Blackfan anemia the RSP19 gene is mutated in 20-25% of patients. Heterozygote ELA2 mutations are found in 60-80% of severe congenital neutropenia patients. All patients with congenital amegakaryocytic thrombocytopenia have mutations in the thrombopoietin receptor gene c-Mpl.
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PMID:Current diagnosis of inherited bone marrow failure syndromes. 1745 74

Shwachman-Diamond syndrome (SDS) is an autosomal recessive disorder characterized by bone marrow failure, exocrine pancreatic dysfunction, and leukemia predisposition. Mutations in the SBDS gene are identified in most patients with SDS. SBDS encodes a highly conserved protein of unknown function. Data from SBDS orthologs suggest that SBDS may play a role in ribosome biogenesis or RNA processing. Human SBDS is enriched in the nucleolus, the major cellular site of ribosome biogenesis. Here we report that SBDS nucleolar localization is dependent on active rRNA transcription. Cells from patients with SDS or Diamond-Blackfan anemia are hypersensitive to low doses of actinomycin D, an inhibitor of rRNA transcription. The addition of wild-type SBDS complements the actinomycin D hypersensitivity of SDS patient cells. SBDS migrates together with the 60S large ribosomal subunit in sucrose gradients and coprecipitates with 28S ribosomal RNA (rRNA). Loss of SBDS is not associated with a discrete block in rRNA maturation or with decreased levels of the 60S ribosomal subunit. SBDS forms a protein complex with nucleophosmin, a multifunctional protein implicated in ribosome biogenesis and leukemogenesis. Our studies support the addition of SDS to the growing list of human bone marrow failure syndromes involving the ribosome.
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PMID:The human Shwachman-Diamond syndrome protein, SBDS, associates with ribosomal RNA. 1747 9

Shwachman-Diamond syndrome (SDS; OMIM 260400), an inherited bone marrow failure syndrome, is caused by mutations in both alleles of the SBDS gene, which encodes a protein of unknown function. Here we report heterozygosity for the 258 + 2 T>C SBDS gene mutation previously identified in SDS patients in 4 of 91 patients with apparently acquired aplastic anemia (AA) but not in 276 ethnically matched controls (Fisher exact test, P < .004). Affected patients were young and had a poor outcome; they had reduced SBDS expression but no evidence of the pancreatic exocrine failure or skeletal abnormalities typical of SDS. Length of telomeres in granulocytes of SBDS heterozygous patients was short for their age, and in SDS patients with both SBDS alleles affected further analyzed, granulocytes' telomeres were even shorter, correlating in length with SBDS expression. Higher heterogeneity in telomere length also was observed in SDS patients. Telomerase activity of SBDS-deficient patients' lymphocytes was comparable with controls, and no physical interaction between SBDS protein and telomerase complex components (TERT or TERC) was established. We propose that heterozygosity for the 258 + 2 T>C SBDS mutation predisposes to AA by accelerating telomere shortening of leukocytes via a telomerase-independent mechanism.
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PMID:Mutations in the SBDS gene in acquired aplastic anemia. 1747 38

Known genetic defects currently account for only a small proportion of patients meeting criteria for 'probable' or 'possible' common variable immunodeficiency (CVID). A 59-year-old male with a 12-year history of CVID on intravenous immunoglobulin (IVIG) is presented who developed bronchiectasis, cytopenias and malabsorption that are recognized complications of CVID. Work-up for his malabsorption suggested the possibility of Shwachman-Diamond syndrome, confirmed by mutation testing. With the identification of the molecular defect in Shwachman-Diamond syndrome (SDS), it is becoming clear that not all SDS patients have the prominent features of neutropenia or pancreatic malabsorption. A meta-analysis of published immunological defects in SDS suggests that four of 14 hypogammaglobulinaemic SDS patients meet criteria for 'possible' CVID. Mutations in the SBDS gene may therefore be the fifth identified molecular defect in CVID.
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PMID:Some cases of common variable immunodeficiency may be due to a mutation in the SBDS gene of Shwachman-Diamond syndrome. 1819 Jun 2

Pancreatic MRI was evaluated in 14 patients with a clinical diagnosis of Shwachman-Diamond syndrome, and the findings were correlated with Shwachman-Bodian-Diamond gene (SBDS) genotype. The findings suggest that patients with mutations in the SBDS gene have a characteristic magnetic resonance imaging pattern of fat-replaced pancreas and that SBDS mutations are unlikely in patients without this pattern.
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PMID:Magnetic resonance imaging findings of the pancreas in patients with Shwachman-Diamond syndrome and mutations in the SBDS gene. 1828 Aug 55

Deficiencies in the SBDS gene result in Shwachman-Diamond syndrome (SDS), an inherited bone marrow failure syndrome associated with leukemia predisposition. SBDS encodes a highly conserved protein previously implicated in ribosome biogenesis. Using human primary bone marrow stromal cells (BMSCs), lymphoblasts, and skin fibroblasts, we show that SBDS stabilized the mitotic spindle to prevent genomic instability. SBDS colocalized with the mitotic spindle in control primary BMSCs, lymphoblasts, and skin fibroblasts and bound to purified microtubules. Recombinant SBDS protein stabilized microtubules in vitro. We observed that primary BMSCs and lymphoblasts from SDS patients exhibited an increased incidence of abnormal mitoses. Similarly, depletion of SBDS by siRNA in human skin fibroblasts resulted in increased mitotic abnormalities and aneuploidy that accumulated over time. Treatment of primary BMSCs and lymphoblasts from SDS patients with nocodazole, a microtubule destabilizing agent, led to increased mitotic arrest and apoptosis, consistent with spindle destabilization. Conversely, SDS patient cells were resistant to taxol, a microtubule stabilizing agent. These findings suggest that spindle instability in SDS contributes to bone marrow failure and leukemogenesis.
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PMID:Mitotic spindle destabilization and genomic instability in Shwachman-Diamond syndrome. 1832 36

Shwachman-Diamond syndrome (SDS) is an autosomal recessive condition that results from mutations in the SBDS gene, at chromosome 7q11. Main features include exocrine pancreatic failure, neutropenia and skeletal dysplasia. This study investigated brain structures by magnetic resonance imaging (MRI) in patients with SDS. MRI of the brain was performed in nine patients (7 males, age range 7-37 years) with SDS and mutations in the SBDS gene and in 18 age- and gender-matched controls. MRI images were assessed visually, and volumetric analyses of the brain matter and structural midsagittal measurements were performed. Eight out of nine SBDS mutation-verified patients reported learning difficulties. Patients with SDS had smaller occipitofrontal head circumferences than the controls (Z-score -1.3 vs. +0.3, P = 0.021), and decreased global brain volume (1.74 L vs. 1.94 L, P = 0.019); both gray matter (P = 0.042) and white matter (P = 0.007) volumes were reduced. Patients with SDS had no macroscopic brain malformations, but they had significantly smaller age- and head size-adjusted areas of posterior fossa (P = 0.006), vermis (P = 0.002), corpus callosum (P = 0.020), and pons (P = 0.002), and significantly larger cerebrum-vermis ratio (P < 0.0001) than the healthy controls. SDS patients had structurally smaller posterior fossa and cerebellar vermis, corpus callosum, and brainstem than the healthy controls. The MRI findings may be related to the neuropsychological features described in SDS.
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PMID:Shwachman-Diamond syndrome is associated with structural brain alterations on MRI. 1847 97

Shwachman-Diamond syndrome (SDS) is an inherited disorder characterized by reduced cellularity in the bone marrow and exocrine pancreas. Most patients have mutations in the SBDS gene, whose functions are unknown. We previously showed that cells deficient in the SBDS protein are characterized by accelerated apoptosis and Fas hypersensitivity, suggesting that the protein might play an important role in Fas-mediated apoptosis. To study the mechanism of Fas hypersensitivity, we compared shRNA-mediated SBDS-knockdown HeLa cells and SDS marrow CD34+ cells for their sensitivity to several groups of apoptosis inducers. Marked hypersensitivity was noticed in response to Fas stimulation, but not to tumor necrosis factor-alpha, DNA-damaging agents, transcription inhibition or protein synthesis inhibition. To identify the Fas signaling factors that cause hypersensitivity, we analyzed the expression of the pathway's proteins. We found that Fas accumulated at the plasma membrane in SBDS-knockdown cells with corresponding expression of Fas transcript 1, the main Fas transcript which contains both the transmembrane domain and the death domain. However, the total levels of Fas protein and mRNA were comparable to controls, and Fas internalization occurred normally. Expression of FADD, caspase-8 and -3 were not elevated and the pathway inhibitors: ERK, c-FLIP and XIAP were not decreased. These results suggest that SBDS loss results in abnormal accumulation of Fas at the plasma membrane, where it sensitizes the cells to stimulation by Fas ligand.
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PMID:SBDS-deficiency results in specific hypersensitivity to Fas stimulation and accumulation of Fas at the plasma membrane. 1900 51

Shwachman-Diamond syndrome (SDS) is an autosomal recessive disorder characterized by bone marrow failure and leukemia predisposition, pancreatic exocrine dysfunction, and skeletal abnormalities, manifesting as skeletal dysplasia and osteoporosis. Mutations in SBDS have been shown to cause SDS, but the function of the SBDS gene product is unclear. Accelerated angiogenesis has recently been described in bone marrow cells from SDS patients. To clarify the unknown function of SBDS, we performed experiments analyzing the cellular effects of depleting SBDS by RNA interference. The growth of HeLa cells constitutively depleted of SBDS was markedly hindered when compared to cells stably transfected with siRNA against an irrelevant control gene. Similarly, growth of HeLa cells induced to express siRNA against SBDS was specifically inhibited. Inducible SBDS knockdown was associated with modestly increased levels of apoptosis, suggesting a partial contribution of this process to growth inhibition. By microarray analysis of knockdown cells, we found marked differences in expression of genes in multiple pathways, and we chose to examine a selected subset more closely using quantitative PCR arrays. In constitutive and inducible SBDS-depleted HeLa cell clones, we found 3- to 6-fold elevated mRNA levels of osteoprotegerin (OPG or TNFRSF11B) and vascular endothelial growth factor-A (VEGF-A). We confirmed significant overexpression of both secreted proteins by ELISA from supernatants of SBDS-depleted HeLa cells. Osteoprotegerin and VEGF-A are known to have diverse effects on osteoclast differentiation, angiogenesis, and monocyte/macrophage migration, all processes that may be aberrant in SDS, and we propose that overexpression of these factors may contribute to its pathology.
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PMID:Depletion of the Shwachman-Diamond syndrome gene product, SBDS, leads to growth inhibition and increased expression of OPG and VEGF-A. 1901 92


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