ORAI1 mutations abolishing store-operated Ca2+ entry cause anhidrotic ectodermal dysplasia with immunodeficiency (EDA-ID)

Publication date: Available online 16 November 2017
Source:Journal of Allergy and Clinical Immunology
Author(s): Jayson Lian, Mario Cuk, Sascha Kahlfuss, Lina Kozhaya, Martin Vaeth, Frédéric Rieux-Laucat, Capucine Picard, Melina J. Benson, Antonia Jakovcevic, Karmen Bilic, Iva Martinac, Peter Stathopulos, Imre Kacskovics, Thomas Vraetz, Carsten Speckmann, Stephan Ehl, Thomas Issekutz, Derya Unutmaz, Stefan Feske
BackgroundStore-operated Ca²⁺ entry (SOCE) through Ca²⁺ release-activated Ca²⁺ (CRAC) channels is an essential signaling pathway in many cell types. CRAC channels are formed by ORAI1, ORAI2 and ORAI3 proteins and activated by stromal interaction molecule 1 (STIM1) and STIM2. Mutations in ORAI1 and STIM1 genes that abolish SOCE cause a combined immunodeficiency (CID) syndrome that is accompanied by autoimmunity and non-immunological symptoms.ObjectiveMolecular and immunological analysis of patients with CID, anhidrosis and ectodermal dysplasia of unknown etiology.MethodsDNA sequencing of ORAI1 gene, modeling of mutations on ORAI1 crystal structure, analysis of ORAI1 mRNA and protein expression, measurements of SOCE, immunological analysis of peripheral blood lymphocyte populations by flow cytometry, histological and ultrastructural analysis of patient tissues.ResultsWe identified 3 novel autosomal recessive mutations in ORAI1 in unrelated kindreds with CID, autoimmunity, ectodermal dysplasia with anhidrosis (EDA) and muscular dysplasia. The patients were homozygous for p.V181SfsX8, p.L194P and p.G98R mutations in the ORAI1 gene that suppressed ORAI1 protein expression and SOCE in the patients' lymphocytes and fibroblasts. Besides impaired T cell cytokine production, ORAI1 mutations were associated with strongly reduced numbers of invariant natural killer (iNKT) and regulatory T (Treg) cells, and altered composition of γδ T cell and NK cell subsets.ConclusionORAI1 null mutations are associated with reduced numbers of iNKT and Treg cells that likely contribute to the patients' immunodeficiency and autoimmunity. ORAI1 deficient patients suffer from dental enamel defects and anhidrosis representing a new form of anhidrotic ectodermal dysplasia with immunodeficiency (EDA-ID) that is distinct from previously reported patients with EDA-ID due to mutations in the NF-kB signaling pathway (IKBKG and NFKBIA).

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