Genetic and phenotypic spectrum associated with IFIH1 gain‐of‐function
Gillian Rice, Sehoon Park, Francesco Gavazzi, Laura Adang, Loveline A. Ayuk, Lien Van Eyck, Luís Seabra, Christophe Barrea, Roberta Battini, Alexandre Bélot, Stefan Berg, Thierry Billette de Villemeur, Annette Bley, Lubov Blumkin, Odile Boespflug‐Tanguy, Tracy A. Briggs, Elise Brimble, Russell C. Dale, Niklas Darín, François‐Guillaume Debray, Valentina De Giorgis, Jonas Denecke, Diane Doummar, Gunilla Drake af Hagelsrum, Despina Eleftheriou, Margherita Estienne, Elisa Fazzi, François Feillet, Jessica Galli, Nicholas Hartog, Julie Harvengt, Bénédicte Héron, Delphine Héron, D. Kelly, Dorit Lev, Virginie Levrat, John H. Livingston, Itxaso Martí, Cyril Mignot, Fanny Mochel, Marie‐Christine Nouguès, Ilena Oppermann, Belén Pérez‐Dueñas, Bernt Popp, Mathieu P. Rodero, Diana Rodriguez, Veronica Saletti, C. M. SHARPE, Davide Tonduti, Gayatri Vadlamani, Keith Van Haren, Miguel Tomás Vila, Julie Vogt, Evangeline Wassmer, Arnaud Wiedemann, Callum Wilson, Ayelet Zerem, Christiane Zweier, Sameer M. Zuberi, Simona Orcesi, Adeline Vanderver, Sun Hur, Yanick J. Crow
Abstract
IFIH1 gain-of-function has been reported as a cause of a type I interferonopathy encompassing a spectrum of autoinflammatory phenotypes including Aicardi-Goutières syndrome and Singleton Merten syndrome. Ascertaining patients through a European and North American collaboration, we set out to describe the molecular, clinical and interferon status of a cohort of individuals with pathogenic heterozygous mutations in IFIH1. We identified 74 individuals from 51 families segregating a total of 27 likely pathogenic mutations in IFIH1. Ten adult individuals, 13.5% of all mutation carriers, were clinically asymptomatic (with seven of these aged over 50 years). All mutations were associated with enhanced type I interferon signaling, including six variants (22%) which were predicted as benign according to multiple in silico pathogenicity programs. The identified mutations cluster close to the ATP binding region of the protein. These data confirm variable expression and nonpenetrance as important characteristics of the IFIH1 genotype, a consistent association with enhanced type I interferon signaling, and a common mutational mechanism involving increased RNA binding affinity or decreased efficiency of ATP hydrolysis and filament disassembly rate.