ORAI1 and severe combined immunodeficiency: The analysis of Ca2+ influx measurements in a genome-wide screen in patients with a form of hereditary severe combined immune deficiency (SCID) syndrome as well as in Drosophila S2R+ cells identified the fly gene olf186-F (named Orai or CRACM1 CRAC modulator-1) as a modulator of Drosophila CRAC currents, and a human homolog on chromosome 12, Orai1, was found to be mutated in SCID patients, leading to the loss of CRAC channel activity [1,2,3].