Background：The protein encoded by this gene is an important signaling component of many interleukin receptors, including those of interleukin -2, -4, -7 and -21, and is thus referred to as the common gamma chain. Mutations in this gene cause X-linked severe combined immunodeficiency （XSCID）, as well as X-linked combined immunodeficiency （XCID）, a less severe immunodeficiency disorder.
