X-Linked Agammaglobulinemia Case with TH Domain Missense Mutation in Bruton Tyrosine Kinase.
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ABSTRACT:
SUBMITTER: Agrebi N
PROVIDER: S-EPMC8068703 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BackgroundX-linked agammaglobulinemia (XLA) is a rare inherited disease characterized by recurrent bacterial infections, a paucity or absence of peripheral lymphoid tissue, an absence of circulating B cells, and marked depression of serum IgG, IgA, and IgM. Germline mutation of the BTK gene has been identified as a cause of XLA. These mutations cause defects in early B cell development.Case presentationIn this study, we report a variant form of XLA with partial B cell function that results from a missense mutation (c.1117C > G) in exon 13 of the BTK gene. A genetic analysis of the family revealed an affected male sibling with a c.1117C > G mutation. He was observed with low level of serum immunoglobulin and CD19+ B cell and received the IVIG replacement therapy regularly in follow up. Four female carriers were found.ConclusionBTK mutation analysis is necessary in the diagnosis of XLA and may be used for subsequent genetic counseling, carrier detection and prenatal diagnosis.
| S-EPMC4286934 | biostudies-literature
Project description:BackgroundX-linked agammaglobulinemia is a primary immunodeficiency disease caused by gene mutations of Bruton's tyrosine kinase (BTK). We found a new mutation point and summarized the correlation analysis and performed a literature review.Case summaryThe proband was a 5-year-old boy. He was admitted to our hospital due to a recurrent cough and a fever that had persisted for a month. He had a history of multiple respiratory infections and sinusitis. There was no immunodeficiency or recurrent infection history among his family members. Agammaglobulinemia was characterized as follows: Immunoglobulin (Ig) A, 90.0 mg/dL (90-450 mg/dL); IgG, 20.0 mg/dL (800-1800 mg/dL); and IgM, 18.0 mg/dL (60-280 mg/dL). Notably, the assessment of IgG subtypes revealed the following very low levels: Subtype 1, 0.26 g/L (3.62-12.28 g/L); subtype 2, 0.10 g/L (0.57-2.9 g/L); subtype 3, 0.009 g/L (0.129-0.789 g/L); and subtype 4, 0.003 g/L (0.013-1.446 g/L). Cellular immunological test results were as follows: CD3, 74.6% (50%-84.0%); CD4, 47.3% (27.0%-51.0%); and CD8, 24.9% (15.0%-44.0%). A de novo hemizygous deletion in BTK was detected: c.902_c.904delAAG/p.E301del. Transcript levels of the mutant BTK were similar to those of the wild-type gene, though overexpression resulted in markedly reduced levels of mutant BTK (9.49% ± 1.58%), relative to the wild-type BTK (75.8% ± 2.98%, P < 0.01).ConclusionThis case of X-linked agammaglobulinemia was attributed to a de novo hemizygous deletion mutation in BTK (c.902_c.904delAAG/p.E301del). The mutation resulted in markedly reduced BTK protein stability in vitro.
| S-EPMC7479573 | biostudies-literature
Project description:X chromosome-linked agammaglobulinemia is a life-threatening disease that involves a failure in normal development of B lymphocytes and is associated with missense mutations in BTK, a gene encoding a cytoplasmic tyrosine kinase (Bruton agammaglobulinemia tyrosine kinase, EC 2.7.1.112), a member of the Tec family of protein-tyrosine kinases. The genomic organization has been determined by using conventional restriction fragment mapping, extended DNA sequencing, and PCR fragment-sizing approaches. The DNA sequences of the 18 coding exons composing BTK and their flanking-region sequences are reported; an additional exon(s) encodes a 5' untranslated segment. Single-base-pair substitutions and 4-nt deletions resulted in amino acid replacement, premature termination, frameshift, and exon deletion in a group of X chromosome-linked agammaglobulinemia patients exhibiting different clinical presentations and courses. The nature of the mutations is interpreted in terms of the genomic organization of the BTK gene and the disease course in individual patients. Several examples are found in which the same mutation occurs in unrelated patients, and one of these mutations occurs at the same codon that is substituted in the murine form of BTK, resulting in X chromosome-linked immunodeficiency disease. Considerable variation in presentation and disease course in X chromosome-linked agammaglobulinemia appears associated with the nature and position of different missense mutations.
| S-EPMC44747 | biostudies-other
Project description:Discovery of Bruton's tyrosine kinase (BTK) mutations as the cause for X-linked agammaglobulinemia was a milestone in understanding the genetic basis of primary immunodeficiencies. Since then, studies have highlighted the critical role of this enzyme in B-cell development and function, and particularly in B-cell receptor signaling. Because its deletion affects mostly B cells, BTK has become an attractive therapeutic target in autoimmune disorders and B-cell malignancies. Ibrutinib (PCI-32765) is the most advanced BTK inhibitor in clinical testing, with ongoing phase III clinical trials in patients with chronic lymphocytic leukemia and mantle-cell lymphoma. In this article, we discuss key discoveries related to BTK and clinically relevant aspects of BTK inhibitors, and we provide an outlook into clinical development and open questions regarding BTK inhibitor therapy.
| S-EPMC5073382 | biostudies-literature
Project description:Bruton tyrosine kinase (BTK) is a nonreceptor tyrosine kinase that plays a central role in the signal transduction of the B-cell antigen receptor and other cell surface receptors, both in normal and malignant B lymphocytes. B-cell antigen receptor signaling is activated in secondary lymphatic organs and drives the proliferation of malignant B cells, including chronic lymphocytic leukemia (CLL) cells. During the last 10 years, BTK inhibitors (BTKis) are increasingly replacing chemotherapy-based regimen, especially in patients with CLL and mantle cell lymphoma (MCL). Bruton tyrosine kinase inhibitors are particularly active in patients with CLL and MCL, but also received approval for Waldenström macroglobulinemia, small lymphocytic lymphoma, marginal zone lymphoma, and chronic graft-versus-host disease. Current clinical practice is continuous long-term administration of BTKi, which can be complicated by adverse effects or the development of drug resistance. Alternatives to long-term use of BTKi are being developed, such as combination therapies, permitting for limited duration therapy. Second-generation BTKis are under development, which differ from ibrutinib, the first-in-class BTKi, in their specificity for BTK, and therefore may differentiate themselves from ibrutinib in terms of adverse effects or efficacy.
| S-EPMC7083517 | biostudies-literature
Project description:Inhibition of Bruton's tyrosine kinase (BTK) has revolutionized the treatment landscape for patients with chronic lymphocytic leukemia (CLL). By targeting this critical kinase in proximal B-cell receptor signaling, BTK inhibitors (BTKis) impair cell proliferation, migration, and activation of NF-?B. Clinically, because indefinite inhibition is a mainstay of therapy, there is an extended period of exposure in which adverse effects can develop. Given the impressive efficacy and activity of BTKis in the treatment of patients with CLL, appropriate management of treatment-emergent adverse events (AEs) is of paramount importance. Here we review the BTKi landscape and present the available toxicity and safety data for each agent. The long-term toxicity profile of ibrutinib, a first-in-class inhibitor, is well characterized and includes a clinically significant incidence of cardiac arrhythmias, bleeding, infection, diarrhea, arthralgias, and hypertension. Acalabrutinib, the initial second-generation BTKi to earn approval from the US Food and Drug Administration, demonstrates improved kinase selectivity for BTK, with commonly observed adverse reactions including infection, headache, and diarrhea. Mediated by both on-target inhibition of BTK and variable off-target inhibition of other kinases including interleukin-2-inducible T-cell kinase (ITK), tyrosine-protein kinase (TEC), and endothelial growth factor receptor (EGFR), the toxicity profile of BTKis is closely linked to their pattern of kinase binding. Other emerging BTKis include second-generation agents with variable degrees of kinase selectivity and third-generation agents that exhibit reversible noncovalent binding to BTK. We also highlight critical considerations for the prevention and monitoring of AEs and offer practical management strategies for treatment-emergent toxicities.
| S-EPMC7727553 | biostudies-literature
Project description:Bruton tyrosine kinase (BTK) is a critical effector molecule for B cell development and plays a major role in lymphoma genesis. Ibrutinib is the first-generation BTK inhibitor. Ibrutinib has off-target effects on EGFR, ITK, and Tec family kinases, which explains the untoward effects of ibrutinib. Resistance to ibrutinib was also reported. The C481S mutation in the BTK kinase domain was reported to be a major mechanism of resistance to ibrutinib. This review summarizes the clinical development of novel BTK inhibitors, ACP-196 (acalabrutinib), ONO/GS-4059, and BGB-3111.
| S-EPMC5010774 | biostudies-literature
Project description:X-linked agammaglobulinemia (XLA) is an extremely rare inherited primary immunodeficiency characterized by recurrent bacterial infections, decrease in number of mature B cells and low serum immunoglobulins. XLA is caused by mutations in the gene encoding Bruton's tyrosine kinase. We report a case of a young Indian boy suspected to have XLA. Immunophenotyping was performed for the affected child using CD20, CD19 and CD3 antibodies. Whole exome sequencing was performed using trio-based approach. The variants were further analyzed using capillary sequencing in the trio as well as maternal grandmother. Initial immunophenotyping in the affected child showed decreased count of CD19+ B cells. To strengthen the clinical findings and confirm the diagnosis of XLA, we performed whole exome sequencing. Our analysis identified a novel frameshift insertion (c.1325dupT) in the BTK gene, which was further validated by Sanger sequencing. Our approach shows the potential in using whole exome sequencing to pinpoint the molecular lesion, enabling timely diagnosis and genetic counseling, and potentially offering prenatal genetic testing for the family.
| S-EPMC5590079 | biostudies-literature
Project description:Bruton tyrosine kinase (BTK) inhibitors have taken a central role in the management of patients with Waldenström macroglobulinemia and are the only agents approved by the Food and Drug Administration (FDA) to treat these patients. Although associated with high rates of durable responses, unmet needs with BTK inhibitor therapy include indefinite duration therapy, high cost, scarcity of complete responses, and lower rates and shorter duration of response in patients with CXCR4 mutations. Herein, we review the data supporting the use of covalent BTK inhibitors, selected management issues, clinical trials with covalent BTK inhibitor combination regimens, and up-and-coming non-covalent BTK inhibitors.
| S-EPMC10107762 | biostudies-literature
Project description:The covalent Bruton tyrosine kinase (BTK) inhibitor ibrutinib is highly efficacious against multiple B-cell malignancies. However, it is not selective for BTK, and multiple mechanisms of resistance, including the C481S-BTK mutation, can compromise its efficacy. We hypothesized that small-molecule-induced BTK degradation may overcome some of the limitations of traditional enzymatic inhibitors. Here, we demonstrate that BTK degradation results in potent suppression of signaling and proliferation in cancer cells and that BTK degraders efficiently degrade C481S-BTK. Moreover, we discovered DD-03-171, an optimized lead compound that exhibits enhanced antiproliferative effects on mantle cell lymphoma (MCL) cells in vitro by degrading BTK, IKFZ1, and IKFZ3 as well as efficacy against patient-derived xenografts in vivo. Thus, "triple degradation" may be an effective therapeutic approach for treating MCL and overcoming ibrutinib resistance, thereby addressing a major unmet need in the treatment of MCL and other B-cell lymphomas.
| S-EPMC6396177 | biostudies-literature