Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q00604 (X-linked)
 16,883 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Severe combined immunodeficiency (SCID) is a rare pediatric medical emergency in Taiwan. The early diagnosis of infants with SCID is very important because it can save the life of these critical infants. The essential clues important for early diagnosis of SCID patients include positive family history of early infant death, paucity of tonsil and lymphoid tissue, cutaneous fungal infection and lymphopenia. Severe combined immunodeficiency is a heterogeneous group of inherited disorders characterized by the failure of both cellular and humoral immunity. It can be categorized into SCID with B-lymphocytes predominant (T-B+SCID) and SCID with paucity of B-lymphocytes (T-B-SCID), according to the number of B-lymphocytes in the patient's peripheral circulation. We report two male infants with T-B+SCID who had been suffering from severe pulmonary distress with persistent O2 desaturation when they were transferred to our pediatric intensive care unit. Tracing back these infant's family histories, it was discovered that both of them had an elder brother who had died to overwhelming infection within the first year of life, and Pneumocystis carinii pneumonitis (PCP) was confirmed in the elder brother of case 2. After hospitalization, the immune condition of these two infants were evaluated which showed a decrease in T-cell and NK cell number, an increase in B-cell number, and decreased serum levels of all the Igs except IgM, which was elevated in case 1. These were the diagnostic immunological findings for T-B+SCID, which included X-linked SCID and Jak-3-deficient SCID. During hospitalization, severe mucocutaneous candidiasis and PCP were noted and confirmed in case 1 and PCP was highly suspected in case 2. Bone marrow transplantation, the only curable treatment for T-B+SCID at present, could not be performed in these two patients because of their grave clinical condition. Both of them expired due to their progressively downhill pulmonary conditions.
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PMID:Severe combined immunodeficiency with B-lymphocytes (T-B+SCID): report of two cases. 992 17

Mutations of the common gamma (gammac) chain result in X-linked SCID (X-SCID), which is characterized by the reduction in number or absence of peripheral blood T cells and natural killer (NK) cells, with retention of normal numbers of B cells. In the present study we describe a novel mutant gammac chain of an X-SCID patient with a typical X-SCID phenotype. This mutant receptor subunit is able to associate with Jak3 to transduce a weak signal. The Jak3-specific action is demonstrated by the induction of gene expression through the haematopoietin receptor response element (HRRE) by IL-2 and IL-4 in the experimental model of transiently transfected hepatoma cells over-expressing Jak3. This result suggests that a threshold in the gammac-Jak3 interaction determines the X-SCID phenotype.
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PMID:A novel mutant gammac chain from a patient with typical phenotype of X-linked severe combined immunodeficiency (SCID) has partial signalling function for mediating IL-2 and IL-4 receptor action. 993 65

In order to increase the awareness of otolaryngologists of severe combined immunodeficiency syndrome (SCIDS) so they may contribute to an earlier diagnosis of this disorder, we performed a retrospective chart review of a multicenter series from 2 children's hospital medical centers. Eighteen cases were identified, and 14 had an otolaryngological presentation. The average age of presentation was 3.3 months, and 72% were males. Most cases were inherited in an X-linked fashion. Five patients had thrush; 4 had recurrent otitis media. Other otolaryngological presentations included cough, mouth ulcers, pharyngitis, mastoiditis, and bilateral neck abscess. The most severe form of immunodeficiency, SCIDS is a rare condition that involves a disorder in both T and B cell functions. The manifestations involving the head and neck include recurrent upper respiratory tract infections, otitis media, thrush, oral ulcers, and abscesses. It is important that SCIDS be considered in any infant with recurrences of these common infections.
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PMID:Severe combined immunodeficiency: otolaryngological presentation and management. 1021 90

Severe combined immunodeficiency is a heterogenous syndrome of varied genetic origins of which the X-linked type is the commonest (XSCID). The most sensitive method for diagnosis of XSCID in the absence of X-linked inheritance pattern is by mutation analysis. In this report we have performed mutation analysis in 13 unrelated boys transplanted (BMT) for SCID without a known cause to determine the frequency of XSCID. Five boys had an affected male relative. We also assessed the utility of hair roots for children without pre-transplant blood stored for mutation analysis since donor genotype was expressed in peripheral blood post BMT. Screening was performed by analysis of single-strand conformational polymorphism (SSCP) followed by sequencing of candidate exons. Mutations were found in 11 cases, of which six were sporadic, and maternal mosaicism was found in one family. Three mothers of the six sporadic cases were identified as carriers. The majority (6/8) of boys with SCID had gammac deficiency despite the absence of X-linked inheritance pattern. The significant frequency of de novo mutations and the occurrence of maternal germline mosaicism highlights the importance of mutation analysis. The strategy of using DNA from hair roots was particularly valuable where no pre-transplant blood was stored. Characterization of the mutations will also enable research into the correction of these genetic defects.
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PMID:Identification of X-linked severe combined immunodeficiency by mutation analysis of blood and hair roots. 1044 86

Expansion of early lymphoid progenitors requires interleukin-7 (IL-7), which functions through gamma(c)-mediated receptor activation of Jak3. Jak3 deficiency is a cause of severe combined immunodeficiency (SCID) in humans and mice. IL-3 activates many of the same signaling pathways as IL-7, such as Stat5, but achieves this effect through the activation of Jak2 rather than Jak3. We hypothesized that expansion of an IL-7-responsive precursor population through a Jak3-independent pathway using IL-3 may stimulate early lymphoid progenitors and restore lymphopoiesis in Jak3(-/-) mice. Newborn Jak3(-/-) mice that were injected with IL-3 demonstrated thymic enlargement, a 2- to 20-fold increase in thymocyte numbers, and up to a 10-fold expansion in the number of CD4(+), CD8(+), and B220(+)/IgM(+) splenic lymphocytes, consistent with an effect upon an early lymphoid progenitor population. In contrast to control mice, IL-3-treated Jak3(-/-) mice challenged with the allogeneic major histocompatibility complex (MHC) class I-bearing tumor P815 developed a specific CD8-dependent cytotoxic T lymphocyte (CTL) response. IL-3-treated mice also mounted influenza-specific CTL responses and survival was prolonged. The beneficial effects of IL-3 are proposed to be produced by stimulation of a lymphoid precursor population of IL-7Ralpha(+)/IL-3Ralpha(+) cells that we identified in wild-type bone marrow. In vitro, we show that an early IL-7R(+) lymphoid progenitor population expresses IL-3R and proliferates in response to IL-3 and that IL-3 activates Stat5 comparably to IL-7. Clinically, IL-3 may therefore be useful treatment for X-linked and Jak3-deficient SCID patients who lack bone marrow donors.
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PMID:Reconstitution of early lymphoid proliferation and immune function in Jak3-deficient mice by interleukin-3. 1047 19

The cytokine receptor common gamma chain mutation in X-linked SCID results in a failure of T and NK cell development and an as yet undefined defect of B cells. Using immunoglobulin isotype-specific reverse transcription-PCR we show that although hematopoietic stem cell transplantation restores a diverse repertoire of class-switched B cell clones, on further analysis these are almost all of donor origin. This suggests that host B cells, which predominate after unconditioned transplantation, are still defective even in the presence of normal T cells. These studies imply that effective humoral reconstitution can only be achieved by the engraftment of normal donor B cells.
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PMID:Intrinsic defects of B cell function in X-linked severe combined immunodeficiency. 1074 87

Severe combined immunodeficiency-X1 (SCID-X1) is an X-linked inherited disorder characterized by an early block in T and natural killer (NK) lymphocyte differentiation. This block is caused by mutations of the gene encoding the gammac cytokine receptor subunit of interleukin-2, -4, -7, -9, and -15 receptors, which participates in the delivery of growth, survival, and differentiation signals to early lymphoid progenitors. After preclinical studies, a gene therapy trial for SCID-X1 was initiated, based on the use of complementary DNA containing a defective gammac Moloney retrovirus-derived vector and ex vivo infection of CD34+ cells. After a 10-month follow-up period, gammac transgene-expressing T and NK cells were detected in two patients. T, B, and NK cell counts and function, including antigen-specific responses, were comparable to those of age-matched controls. Thus, gene therapy was able to provide full correction of disease phenotype and, hence, clinical benefit.
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PMID:Gene therapy of human severe combined immunodeficiency (SCID)-X1 disease. 1079

Recently, two SCID (severe combined immunodeficiency disease) patients with greatly diminished T cells but normal or increased numbers of B and NK cells (T(-)B(+)NK(+) SCID) were found to have mutations in the gene for the IL-7 receptor. This has established a major role for IL-7-receptor-dependent signaling in T cell development in humans and probably explains the diminished T cell numbers seen in patients with X-linked SCID or SCID that results from Jak3-deficiency.
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PMID:Mutations in the gene for the IL-7 receptor result in T(-)B(+)NK(+) severe combined immunodeficiency disease. 1089 29

Several immunodeficiency-related genes have been identified and a large number of mutations in these genes. Currently, a genetic defect has been determined in more than 2000 patients. Only recently has it become possible to address structure-function effects of these mutations in the corresponding proteins. The consequences of mutations in structure are discussed for Btk in X-linked agammaglobulinemia (XLA), Jak3 in T-B+ severe combined immunodeficiency (SCID), p47phox and p67phox in autosomal chronic granulomatous disease (CGD) and SH2D1 A in X-linked lymphoproliferatine disease (XLP). The experimental and homology modelling derived structures were used to analyze mechanisms related to these diseases.
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PMID:Structure-function effects in primary immunodeficiencies. 1097 97

Combined immune deficiencies comprise a spectrum of genetic disorders characterized by developmental or functional defects of both T and B lymphocytes. Recent progress in cell biology and molecular genetics has unraveled the pathophysiology of most of these defects. In particular, the most common form of severe combined immune deficiency in humans, with lack of circulating T cells, a normal or increased number of B lymphocytes, and an X-linked pattern of inheritance (SCIDXI) has been shown to be due to defects of the IL2RG gene, encoding for the common gamma chain (gammac), shared by several cytokine receptors. Furthermore, defects of the JAK3 gene, encoding for an intracellular tyrosine kinase required for signal transduction through gammac-containing cytokine receptors, have been identified in patients with autosomal recessive T-B+ SCID. Characterization of the functional properties of cytokines that signal through the gammac-JAK3 signaling pathway has been favored by the detailed analysis of SCID patients. Specifically, the key role of IL-7 in promoting T cell development has been substantiated by the identification of rare patients with T-B+ SCID who have a defect in the alpha subunit of the IL-7 receptor (IL7Ralpha). The heterogeneity of genetic defects along the same signaling pathway that may lead to combined immune deficiency is paralleled by the heterogeneity of immunological phenotypes that may associate with defects in the same gene, thus creating a need for detailed immunological and molecular investigations in order to dissect the spectrum of combined immune deficiencies in humans.
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PMID:Combined immunodeficiencies due to defects in signal transduction: defects of the gammac-JAK3 signaling pathway as a model. 1099 86


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