JACI_GUO resubmitted.pdf (951.33 kB)
XRCC4 deficiency in human subjects causes a marked neurological phenotype but no overt immunodeficiency
journal contribution
posted on 2023-06-09, 00:03 authored by Chaowan Guo, Yuka Nakazawa, Lisa Woodbine, Andrea Björkman, Mayuko Shimada, Heather Fawcett, Nan Jia, Kaname Ohyama, Tao-Sheng Li, Yuji Nagayama, Norisato Mitsutake, Qiang Pan-Hammarström, Andrew R Gennery, Alan LehmannAlan Lehmann, Penny Jeggo, Tomoo OgiBackground Nonhomologous end-joining (NHEJ) is the major DNA double-strand break (DSB) repair mechanism in human cells. The final rejoining step requires DNA ligase IV (LIG4) together with the partner proteins X-ray repair cross-complementing protein 4 (XRCC4) and XRCC4-like factor. Patients with mutations in genes encoding LIG4, XRCC4-like factor, or the other NHEJ proteins DNA-dependent protein kinase catalytic subunit and Artemis are DSB repair defective and immunodeficient because of the requirement for NHEJ during V(D)J recombination. Objective We found a patient displaying microcephaly and progressive ataxia but a normal immune response. We sought to determine pathogenic mutations and to describe the molecular pathogenesis of the patient. Methods We performed next-generation exome sequencing. We evaluated the DSB repair activities and V(D)J recombination capacity of the patient's cells, as well as performing a standard blood immunologic characterization. Results We identified causal mutations in the XRCC4 gene. The patient's cells are radiosensitive and display the most severe DSB repair defect we have encountered using patient-derived cell lines. In marked contrast, a V(D)J recombination plasmid assay revealed that the patient's cells did not display the junction abnormalities that are characteristic of other NHEJ-defective cell lines. The mutant protein can interact efficiently with LIG4 and functions normally in in vitro assays and when transiently expressed in vivo. However, the mutation makes the protein unstable, and it undergoes proteasome-mediated degradation. Conclusion Our findings reveal a novel separation of impact phenotype: there is a pronounced DSB repair defect and marked clinical neurological manifestation but no clinical immunodeficiency.
History
Publication status
- Published
File Version
- Accepted version
Journal
Journal of Allergy and Clinical ImmunologyISSN
0091-6749Publisher
ElsevierExternal DOI
Issue
4Volume
136Page range
1007-1017Department affiliated with
- Sussex Centre for Genome Damage Stability Publications
Full text available
- Yes
Peer reviewed?
- Yes
Legacy Posted Date
2016-01-18First Open Access (FOA) Date
2016-01-18First Compliant Deposit (FCD) Date
2016-01-18Usage metrics
Categories
No categories selectedKeywords
Licence
Exports
RefWorks
BibTeX
Ref. manager
Endnote
DataCite
NLM
DC