ORAI1 and severe combined immunodeficiency: ORAI1, which is also known as calcium release-activated calcium modulator 1 (CRACM1) and transmembrane protein 142A (TMEM142A) was identified in 2006 by Feske et al. (2006) through a genome-wide screen of linkage in SCID patients that identified a missense mutation in ORAI1, which resulted in impaired ICRAC in T cells, as well as a genome-wide RNA interference screen in Drosophila melanogaster which provided support that ORAI1 is the key component of CRAC channels (Figure 1).