1. IL36RN Mutations Affect Protein Expression and Function: A Basis for Genotype-Phenotype Correlation in Pustular Diseases
- Author
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Farida Otsmane, Marine Madrange, Houria Sahel, Asma Smahi, Marie Tauber, Emmanuelle Bourrat, Naima Smahi, Mohamed Makrelouf, Amel Khelil, Khaled Boubridaa, Xue-Yuan Pei, Bakar Bouajar, Hervé Bachelez, Amel Chiali, Manuelle Viguier, Yamina Hamel, Slaheddine Marrakchi, Hamida Turki, Elodie Bal, and Akila Zenati
- Subjects
Adult ,Male ,0301 basic medicine ,Genotype ,Pustular Eruption ,Dermatology ,Gene mutation ,Biology ,Compound heterozygosity ,Risk Assessment ,Biochemistry ,03 medical and health sciences ,Psoriasis ,medicine ,Humans ,Child ,Molecular Biology ,Genetic Association Studies ,Interleukins ,Acrodermatitis ,Wild type ,Cell Biology ,Prognosis ,medicine.disease ,Phenotype ,030104 developmental biology ,Gene Expression Regulation ,Interleukin 36 receptor antagonist ,Child, Preschool ,Mutation ,Immunology ,Disease Progression ,Generalized pustular psoriasis ,Female - Abstract
Homozygous or compound heterozygous IL36RN gene mutations underlie the pathogenesis of psoriasis-related pustular eruptions including generalized pustular psoriasis, palmoplantar pustular psoriasis, acrodermatitis continua of Hallopeau, and acute generalized exanthematous pustular eruption. We identified two unreported IL36RN homozygous mutations (c.41C>A/p.Ser14X and c.420_426del/p.Gly141MetfsX29) in patients with familial generalized pustular psoriasis. We analyzed the impact of a spectrum of IL36RN mutations on IL-36 receptor antagonist protein by using site-directed mutagenesis and expression in HEK293T cells. This enabled us to differentiate null mutations with complete absence of IL-36 receptor antagonist (the two previously unreported mutations, c.80T>C/p.Leu27Pro, c.28C>T/p.Arg10X, c.280G>T/p.Glu94X, c.368C>G/p.Thr123Arg, c.368C>T/p.Thr123Met, and c.227C>T/p.Pro76Leu) from mutations with decreased (c.95A>G/p.His32Arg, c.142C>T/p.Arg48Trp, and c.308C>T/p.Ser113Leu) or unchanged (c.304C>T/p.Arg102Trp and c.104A>G/p.Lys35Arg) protein expression. Functional assays measuring the impact of mutations on the capacity to repress IL-36–dependent activation of the NF-κB pathway showed complete functional impairment for null mutations, whereas partial or no impairment was observed for other mutations considered as hypomorphic. Finally, null mutations were associated with severe clinical phenotypes (generalized pustular psoriasis, acute generalized exanthematous pustular eruption), whereas hypomorphic mutations were identified in both localized (palmoplantar pustular psoriasis, acrodermatitis continua of Hallopeau) and generalized variants. These results provide a preliminary basis for genotype-phenotype correlation in patients with deficiency of the IL-36Ra (DITRA), and suggest the involvement of other factors in the modulation of clinical expression.
- Published
- 2016