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Assing K, Jørgensen SE, Sandgaard KS, De Keukeleere K, B-Hansen M, Petersen MS, Hartling UB, Vaal TMKD, Nielsen C, Jakobsen MA, Watt E, Adams S, Hao Q, Fagerberg C, Mogensen TH. A Novel CDC42 Variant with Impaired Thymopoiesis, IL-7R Signaling, PAK1 Binding, and TCR Repertoire Diversity. J Clin Immunol 2023; 43:1927-1940. [PMID: 37581646 PMCID: PMC10661826 DOI: 10.1007/s10875-023-01561-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 07/30/2023] [Indexed: 08/16/2023]
Abstract
Genetic variants in cell division cycle 42 (CDC42) can manifest with dysmorphic features, autoinflammation, hemophagocytic lymphohistiocytosis, and thrombocytopenia, whereas defective thymopoiesis is a rare disease manifestation. We report a novel CDC42 missense variant (c.46A > G, p.Lys16Glu) resulting in infection and HPV-driven carcinogenesis in the mosaic mother and impaired thymopoiesis and profound T cell lymphopenia in the heterozygous daughter identified through newborn screening for SCID. We found that surface expression of IL-7Rα (CD127) was decreased, consistent with reduced IL-7-induced STAT5 phosphorylation and accelerated apoptotic T cell death. Consistent with the vital role of IL-7 in regulating thymopoiesis, both patients displayed reduced T cell receptor CDR3 repertoires. Moreover, the CDC42 variant prevented binding to the downstream effector, p21-activated kinase (PAK)1, suggesting this impaired interaction to underlie reduced IL-7Rα expression and signaling. Here, we provide the first report of severely compromised thymopoiesis and perturbed IL-7Rα signaling caused by a novel CDC42 variant and presenting with diverging clinical and immunological phenotypes in patients.
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Affiliation(s)
- Kristian Assing
- Department of Clinical Immunology, Odense University Hospital (OUH), Odense, Denmark.
| | | | | | | | - Marie B-Hansen
- Danish Center for Neonatal Screening, Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark
| | - Mikkel S Petersen
- Department of Clinical Immunology, Aarhus University Hospital (AUH), Aarhus, Denmark
| | - Ulla B Hartling
- Department of Pediatrics, Odense University Hospital (OUH), Odense, Denmark
| | | | - Christian Nielsen
- Department of Clinical Immunology, Odense University Hospital (OUH), Odense, Denmark
| | - Marianne A Jakobsen
- Department of Clinical Immunology, Odense University Hospital (OUH), Odense, Denmark
| | - Eleanor Watt
- Infection, Immunity and Inflammation Section, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Stuart Adams
- Infection, Immunity and Inflammation Section, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Qin Hao
- Department of Clinical Genetics, Odense University Hospital (OUH), Odense, Denmark
| | - Christina Fagerberg
- Department of Clinical Genetics, Odense University Hospital (OUH), Odense, Denmark
| | - Trine H Mogensen
- Department of Biomedicine, Aarhus University (AU), Aarhus, Denmark.
- Department of Infectious Diseases, Aarhus University Hospital (AUH), Aarhus, Denmark.
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