Background: Cherubism is most commonly caused by rare heterozygous gain-of-function (GOF) missense variants in SH3BP2, which appear to signal through phospholipase C gamma 2 (PLCG2) to cause excessive osteoclast activity leading to expansile lesions in facial bones in childhood. GOF variants in PLCG2 lead to autoinflammatory PLCG2-associated antibody deficiency and immune dysregulation (autoinflammatory PLAID, or PLAID-GOF), characterized by variably penetrant autoinflammatory, autoimmune, infectious, and atopic manifestations. Cherubism has not been reported in PLAID to date.
Objective: We determined whether GOF PLCG2 variants may be associated with cherubism.
Methods: Clinical, laboratory, and genomic data from 2 patients with cherubism and other clinical symptoms observed in patients with PLCG2 variants were reviewed. Primary B-cell receptor-induced calcium flux was assessed by flow cytometry.
Results: Two patients with lesions consistent with cherubism but no SH3BP2 variants were found to have rare PLCG2 variants previously shown to be GOF in vitro, leading to increased primary B-cell receptor-induced calcium flux in one patient's B cells. Variable humoral defects, autoinflammatory rash, and other clinical and laboratory findings consistent with PLAID were observed as well.
Conclusion: GOF PLCG2 variants likely represent a novel genetic driver of cherubism and should be assessed in SH3BP2-negative cases. Expansile bony lesions expand the phenotypic landscape of autoinflammatory PLAID, and bone imaging should be considered in PLAID patients.
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http://dx.doi.org/10.1016/j.jaci.2024.08.016 | DOI Listing |
J Allergy Clin Immunol
December 2024
Translational Genetics and Genomics Section, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health (NIH), Bethesda, MD. Electronic address:
Background: Phospholipase Cγ2 (PLCγ2) is an important signaling molecule that receives and transmits signals from various cell surface receptors in most hematopoietic lineages. Variants of PLCG2 cause PLCγ2-associated immune dysregulation (PLAID), a family of conditions that are classified by mutational effect. PLAID with cold urticaria (PLAID-CU) is caused by in-frame deletions of PLCG2 that are dominant negative at physiologic temperatures but become spontaneously active at sub-physiologic temperatures.
View Article and Find Full Text PDFJ Neuroinflammation
November 2024
Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL, USA.
Genome-wide association studies have identified a protective mutation in the phospholipase C gamma 2 (PLCG2) gene which confers protection against Alzheimer's disease (AD)-associated cognitive decline. Therefore, PLCG2, which is primarily expressed in immune cells, has become a target of interest for potential therapeutic intervention. The protective allele, known as P522R, has been shown to be hyper-morphic in microglia, increasing phagocytosis of amyloid-beta (Aβ), and increasing the release of inflammatory cytokines.
View Article and Find Full Text PDFAllergol Select
October 2024
Center for Child and Adolescent Health, Helios Hospital Krefeld, Academic Hospital of RWTH Aachen, Krefeld.
Adv Biol Regul
December 2024
Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London, UK. Electronic address:
The phospholipase C enzyme PLCγ2 is best characterised in the context of immune cell regulation. Furthermore, many mutations discovered in PLCγ2 have been linked to the development of complex immune disorders as well as resistance to ibrutinib treatment in chronic lymphocytic leukaemia. Importantly, it has also been found that a rare variant of PLCγ2 (P522R) has a protective role in Alzheimer's disease (AD).
View Article and Find Full Text PDFComput Biol Chem
December 2024
Department of Bioinformatics and Life Science, Soongsil University, 369 Sangdo-ro, Dongjak-gu, Seoul 06978, Republic of Korea. Electronic address:
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