ORAI1 mutations abolishing store-operated Ca2+ entry cause anhidrotic ectodermal dysplasia with immunodeficiency.

BACKGROUND: Store-operated Ca2+ entry (SOCE) through Ca2+ release-activated Ca2+ channels is an essential signaling pathway in many cell types. Ca2+ release-activated Ca2+ channels are formed by ORAI1, ORAI2, and ORAI3 proteins and activated by stromal interaction molecule (STIM) 1 and STIM2. Mutations in the ORAI1 and STIM1 genes that abolish SOCE cause a combined immunodeficiency (CID) syndrome that is accompanied by autoimmunity and nonimmunologic symptoms. OBJECTIVE: We performed molecular and immunologic analysis of patients with CID, anhidrosis, and ectodermal dysplasia of unknown etiology. METHODS: We performed DNA sequencing of the ORAI1 gene, modeling of mutations on ORAI1 crystal structure, analysis of ORAI1 mRNA and protein expression, SOCE measurements, immunologic analysis of peripheral blood lymphocyte populations by using flow cytometry, and histologic and ultrastructural analysis of patient tissues. RESULTS: We identified 3 novel autosomal recessive mutations in ORAI1 in unrelated kindreds with CID, autoimmunity, ectodermal dysplasia with anhidrosis, 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. In addition to impaired T-cell cytokine production, ORAI1 mutations were associated with strongly reduced numbers of invariant natural killer T and regulatory T (Treg) cells and altered composition of γδ T-cell and natural killer cell subsets. CONCLUSION: ORAI1 null mutations are associated with reduced numbers of invariant natural killer T and Treg cells that likely contribute to the patients' immunodeficiency and autoimmunity. ORAI1-deficient patients have dental enamel defects and anhidrosis, representing a new form of anhidrotic ectodermal dysplasia with immunodeficiency that is distinct from previously reported patients with anhidrotic ectodermal dysplasia with immunodeficiency caused by mutations in the nuclear factor κB signaling pathway (IKBKG and NFKBIA).

[Congenital hyperinsulinism--novel insights into etiology, diagnosis and treatment]. / Kongenitalni hiperinzulinizam- -novosti o nastanku, dijagnosticiranju i lijecenju bolesti.

Congenital hyperinsulinism (CHI) is a major cause of persistent hypoglycemia in the neonatal and early infancy periods. Althought the disease is relatively rare with incidence of about 1:25 000-50 000 live births, the importance of the disease should not be underestimated. Namely, prompt recognition and management of patients with CHI is essential, if permanent neurological impairment is to be avoided. CHI is caused by mutations in one of the 7 genes involved in the regulation of insulin secretion in pancreatic beta-cells. It is important to introduce specific medical therapy as soon as diagnosis is established. Severe, neonatal forms of CHI are often resistant to medications, thus they require surgical procedure. The preoperative genetic testing and scintigraphy are indicated to distinguish histological subtypes of the disease (focal vs. diffuse CHI). Patients with focal disease are usually cured after pancreatic resection, while diffuse disease has much worse prognosis. This manuscript offers novel insights into CHI and emphasizes the role of early diagnosis as crucial for succesful treatment that was recently enriched with novel options.