Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0021051 (immunodeficiency)
 71,517 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Bloom's syndrome (BS) is an autosomal recessive disease, caused by mutations in the BLM gene. This gene codes for BLM protein, which is a helicase involved in DNA repair. DNA repair is especially important for the development and maturation of the T and B cells. Since BLM is involved in DNA repair, we aimed to study if BLM deficiency affects T and B cell development and especially somatic hypermutation (SHM) and class switch recombination (CSR) processes. Clinical data of six BS patients was collected, and immunoglobulin serum levels were measured at different time points. In addition, we performed immune phenotyping of the B and T cells and analyzed the SHM and CSR in detail by analyzing IGHA and IGHG transcripts using next-generation sequencing. The serum immunoglobulin levels were relatively low, and patients had an increased number of infections. The absolute number of T, B, and NK cells were low but still in the normal range. Remarkably, all BS patients studied had a high percentage (20-80%) of CD4+ and CD8+ effector memory T cells. The process of SHM seems normal; however, the Ig subclass distribution was not normal, since the BS patients had more IGHG1 and IGHG3 transcripts. In conclusion, BS patients have low number of lymphocytes, but the immunodeficiency seems relatively mild since they have no severe or opportunistic infections. Most changes in the B cell development were seen in the CSR process; however, further studies are necessary to elucidate the exact role of BLM in CSR.
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PMID:Immunodeficiency in Bloom's Syndrome. 2909 65

Bloom syndrome is a rare autosomal recessive disease, in which BLM gene is mutated, leading to genome instability and proneness to malignancy. It is characterized by short stature, sun-sensitive rash and immunodeficiency. We present a case of bloom syndrome with myelodysplasia complicated by acute myeloid leukaemia. This case has new ophthalmologic manifestations. We confirmed the diagnosis by detection of high rate of sister chromatid exchange. The patient received chemotherapy but did not tolerate it well and developed fungal pneumonia.
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PMID:Bloom syndrome with myelodysplastic syndrome that was converted into acute myeloid leukaemia, with new ophthalmologic manifestations: the first report from Syria. 3041 Jul 76

Cellular innate immune sensors of DNA are essential for host defense against invading pathogens. However, the presence of self-DNA inside cells poses a risk of triggering unchecked immune responses. The mechanisms limiting induction of inflammation by self-DNA are poorly understood. BLM RecQ-like helicase is essential for genome integrity and is deficient in Bloom syndrome (BS), a rare genetic disease characterized by genome instability, accumulation of micronuclei, susceptibility to cancer, and immunodeficiency. Here, we show that BLM-deficient fibroblasts show constitutive up-regulation of inflammatory interferon-stimulated gene (ISG) expression, which is mediated by the cGAS-STING-IRF3 cytosolic DNA-sensing pathway. Increased DNA damage or down-regulation of the cytoplasmic exonuclease TREX1 enhances ISG expression in BLM-deficient fibroblasts. cGAS-containing cytoplasmic micronuclei are increased in BS cells. Finally, BS patients demonstrate elevated ISG expression in peripheral blood. These results reveal that BLM limits ISG induction, thus connecting DNA damage to cellular innate immune response, which may contribute to human pathogenesis.
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PMID:Bloom syndrome protein restrains innate immune sensing of micronuclei by cGAS. 3093 63

We report the case of a young woman who developed, 3 years after stopping Rituximab (RTX) prescribed for immune thrombocytopenia (ITP), a severe immunodeficiency leading to fatal pulmonary Epstein-Barr virus-positive diffuse large B-cell lymphoma. Genetic analysis led us to identify four missense mutations known to affect immune-deficiency-associated genes (FAS-ligand (FASL) gene (p.G167R); perforin-1 (PRF1 (p.R55C) gene; the Bloom syndrome RecQ-Like helicase (BLM) gene and the Moesin (MSN) (p.A122T) gene). The heterozygous mutation in the FASL gene, not present in the Genome Aggregation Database or ClinVar database, could suggest atypical Autoimmune LymphoProliferative Syndrome and its role in this patient's immunodepression is discussed. This observation strengthens the role of FASL gene mutation in severe clinical phenotypes of primary immune deficiency and raises new questions about the genetic background of ITP occurring in young people in a context of immunodeficiency.
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PMID:Fatal Hypogammaglobulinemia 3 Years after Rituximab in a Patient with Immune Thrombocytopenia: An Underlying Genetic Predisposition? 3195 52

Recurrence of severe microbial infections results from a primary immunodeficiency disorder known as major histocompatibility complex class II deficiency or bare lymphocyte syndrome type II. Immunologic function is severely impaired due to the absence of MHC class II molecules on the surface of immune cells. Here, we report a 5-year-old boy with a novel homozygous mutation in RFXANK gene that negatively affects the proper expression of MHC class II molecules by antigen presenting cells. The frame shift mutations in RFXANK gene and negative HLA-DR proteins expression on peripheral blood mononuclear cells were identified and confirmed by whole exome sequencing, Sanger sequencing, and flow cytometry. The patient was referred with long-term severe prolonged diarrhea, fever, coughing, and vomiting. Also, antibiotic resistance, normal T cell, and NK cell counts with low B cell count and reduced serum immunoglobulin level were observed. The patient did not give a dramatic response to intravenous immunoglobulin infusion. The significancy of this report is the novelty of mutation and low B cell count which is not commonly expected in such patients. The final diagnosis of BLS type II is based on WES, Sanger sequencing, and flow cytometric evaluation. Moreover, it seems that the only therapeutic choice is hematopoietic stem cell transplantation.
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PMID:A novel mutation in RFXANK gene and low B cell count in a patient with MHC class II deficiency: a case report. 3257 29

Pathogenic biallelic variants in the BLM/RECQL3 gene cause a rare autosomal recessive disorder called Bloom syndrome (BS). This syndrome is characterized by severe growth delay, immunodeficiency, dermatological manifestations and a predisposition to a wide variety of cancers, often multiple and very early in life. Literature shows that the main mode of BLM inactivation is protein translation termination. We expanded the molecular spectrum of BS by reporting the first deep intronic variant causing intron exonisation. We describe a patient with a clinical phenotype of BS and a strong increase in sister chromatid exchanges (SCE), who was found to be compound heterozygous for a novel nonsense variant c.3379C>T, p.(Gln1127Ter) in exon 18 and a deep intronic variant c.3020-258A>G in intron 15 of the BLM gene. The deep intronic variant creates a high-quality de novo donor splice site, which leads to retention of two intron segments. Both pseudo-exons introduce a premature stop codon into the reading frame and abolish BLM protein expression, confirmed by Western Blot analysis. These findings illustrate the role of non-coding variation in Mendelian disorders and herewith highlight an unmet need in routine testing of Mendelian disorders, being the added value of RNA-based approaches to provide a complete molecular diagnosis.
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PMID:Missing heritability in Bloom syndrome: First report of a deep intronic variant leading to pseudo-exon activation in the BLM gene. 3307 70


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