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Hammarsten O, Lyytikäinen A, Thunström S, Ek T, Fasth A, Ekwall O, Cajander S, Borgström EW, Smith CIE, Johansson P. Clinical measurement of cellular DNA damage hypersensitivity in patients with DNA repair defects. Orphanet J Rare Dis 2022; 17:50. [PMID: 35164800 PMCID: PMC8842932 DOI: 10.1186/s13023-022-02199-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 01/30/2022] [Indexed: 11/18/2022] Open
Abstract
Background DNA repair deficiency disorders are rare inherited diseases arising from pathogenic (disease-causing) variants in genes involved in DNA repair. There are no standardized diagnostic assays for the investigation of pathological significance of unknown variants in DNA repair genes. We hypothesized that our assays for measuring in vitro patient blood cell hypersensitivity to DNA-damaging agents can be used to establish the pathological significance of unknown variants in DNA repair genes. Six patients with variants in the DNA repair genes PRKDC (two siblings), DCLRE1C (two siblings), NBN, and MSH6 were included. Here, we used the cell division assay (CDA) and the γ-H2AX assay, which were both developed and clinically validated by us, to measure patient cell hypersensitivity in response to ionizing radiation, mitomycin C, cytarabine and doxorubicin. Results Radiation hypersensitivity was detected in the two patients with variants in the PRKDC gene (p < 0.0001 for both at 3.5 Gy), and the two patients with DCLRE1C variants (p < 0.0001 at 3.5 Gy for sibling 1 and p < 0.0001 at 1 Gy for sibling 2). The cells from the patients with the PRKDC variant were also deficient in removing γ-H2AX (p < 0.001). The cells from the patient with variants in the NBN gene were hypersensitive to mitomycin C (p = 0.0008) and deficient in both induction and removal of γ-H2AX in response to radiation. Conclusions The combination of the CDA and the γ-H2AX assay is useful in investigating the significance of unknown variants in some DNA repair genes. Supplementary Information The online version contains supplementary material available at 10.1186/s13023-022-02199-8.
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Recio MJ, Dominguez-Pinilla N, Perrig MS, Rodriguez Vigil-Iturrate C, Salmón-Rodriguez N, Martinez Faci C, Castro-Panete MJ, Blas-Espada J, López-Nevado M, Ruiz-Garcia R, Chaparro-García R, Allende LM, Gonzalez-Granado LI. Extreme Phenotypes With Identical Mutations: Two Patients With Same Non-sense NHEJ1 Homozygous Mutation. Front Immunol 2019; 9:2959. [PMID: 30666249 PMCID: PMC6330288 DOI: 10.3389/fimmu.2018.02959] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 11/30/2018] [Indexed: 12/22/2022] Open
Abstract
Cernunnos/XLF deficiency is a rare primary immunodeficiency classified within the DNA repair defects. Patients present with severe growth retardation, microcephaly, lymphopenia and increased cellular sensitivity to ionizing radiation. Here, we describe two unrelated cases with the same non-sense mutation in the NHEJ1 gene showing significant differences in clinical presentation and immunological profile but a similar DNA repair defect.
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Affiliation(s)
- Maria J Recio
- Department of Immunology, Ophthalmology and ENT, School of Medicine, Complutense University, 12 de Octubre Health Research Institute (imas12), Madrid, Spain.,Hospital 12 de Octubre Health Research Institute (imas12), Madrid, Spain
| | - Nerea Dominguez-Pinilla
- Hospital 12 de Octubre Health Research Institute (imas12), Madrid, Spain.,Pediatric Hematology and Oncology Unit, University Hospital Virgen de la Salud, Toledo, Spain
| | - Melina Soledad Perrig
- Department of Immunology, Ophthalmology and ENT, School of Medicine, Complutense University, 12 de Octubre Health Research Institute (imas12), Madrid, Spain.,Hospital 12 de Octubre Health Research Institute (imas12), Madrid, Spain
| | | | - Nerea Salmón-Rodriguez
- Hospital 12 de Octubre Health Research Institute (imas12), Madrid, Spain.,Immunodeficiencies Unit, Pediatrics, University Hospital 12 octubre, Madrid, Spain.,Complutense University School of Medicine, Madrid, Spain
| | - Cristina Martinez Faci
- Pediatric Hematology and Oncology Unit, University Hospital Miguel Servet, Zaragoza, Spain
| | | | - Javier Blas-Espada
- Hospital 12 de Octubre Health Research Institute (imas12), Madrid, Spain.,Department of Immunology, University Hospital 12 Octubre, Madrid, Spain
| | - Marta López-Nevado
- Hospital 12 de Octubre Health Research Institute (imas12), Madrid, Spain.,Department of Immunology, University Hospital 12 Octubre, Madrid, Spain
| | - Raquel Ruiz-Garcia
- Hospital 12 de Octubre Health Research Institute (imas12), Madrid, Spain.,Department of Immunology, University Hospital 12 Octubre, Madrid, Spain
| | - Rebeca Chaparro-García
- Department of Immunology, Ophthalmology and ENT, School of Medicine, Complutense University, 12 de Octubre Health Research Institute (imas12), Madrid, Spain
| | - Luis M Allende
- Hospital 12 de Octubre Health Research Institute (imas12), Madrid, Spain.,Department of Immunology, University Hospital 12 Octubre, Madrid, Spain
| | - Luis Ignacio Gonzalez-Granado
- Hospital 12 de Octubre Health Research Institute (imas12), Madrid, Spain.,Immunodeficiencies Unit, Pediatrics, University Hospital 12 octubre, Madrid, Spain.,Complutense University School of Medicine, Madrid, Spain
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