Dominant negative OTULIN Related Autoinflammatory Syndrome

Biallelic loss of function mutations in the linear chain specific deubiquitinase (DUB) OTULIN (OTU Deubiquitinase With Linear Linkage Specificity) result in OTULIN Related Autoinflammatory Syndrome (ORAS). To date all reported ORAS patients have had homozygous or compound heterozygous loss of function mutations, however we identified a patient with a monoallelic heterozygous mutation p.Cys129Ser. Consistent with the ORAS phenotype, we observed accumulation of linear ubiquitin chains, increased sensitivity to TNF induced cell death and dysregulation of inflammatory signalling in both patient cells and in vitro exogenous expression models. Levels of the mutant OTULIN protein were consistent with wild type OTULIN in patient cells and exogenous expression systems and maintained binding capacity to both LUBAC and linear ubiquitin chains. However, even in a heterozygous context this mutant DUB promoted the global accumulation of linear ubiquitin chains. Furthermore, it allowed accumulation of ubiquitin on the linear ubiquitin chain assembly complex (LUBAC). Altered ubiquitination of LUBAC leads to a dysregulation of NF-κB signalling and promotion of TNF induced cell death. By reporting the first dominant negative mutation driving ORAS this study expands our clinical understanding of Otulin mediated pathology. Summary The dominant negative mutation OTULIN :p.Cys129Ser is sufficient to drive ORAS. Mutant OTULIN outcompetes wildtype for interaction with SHARPIN, this increases M1-ubiquitination of LUBAC and other targets, thereby promoting cell death and consequent inflammatory signalling. ### Competing Interest Statement SLM is a Scientific Advisor for NRG Therapeutics and Odyssey Therapeutics. DK is founder and shareholder of Entact Bio. ### Funding Statement This work was supported by grants from the Australian National Health and Medical Research Council (2003159, 2003756; S.L.M.), fellowships from the Victorian Endowment for Science Knowledge and Innovation (S.L.M.), the HHMI-Wellcome International Research Scholarship (S.L.M.) and the Sylvia and Charles Viertel Foundation (S.L.M.). S.D. acknowledges funding from NHMRC grants (GNT1143412 and GNT2003756). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Ethics committee/IRBs of Sydney Childrens Hospital, National Institutes of Health (NIH) and Walter and Eliza Hall Institute (WEHI), gave ethical approval for this work. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors