Interleukin-2 receptor gamma-chain mutations in severe combined immunodeficiency with B-lymphocytes

Severe combined immunodeficiency (SCID) with a normal number of B-lymphocytes usually demonstrates an X-linked inheritance and now is regarded as an interleukin-2-receptor (IL-2R) gamma-chain gene defect. Here, we report the characterization of mutations in the IL-2R gamma-chain gene of six unrelated SCID patients. One large deletion, one short deletion, one nonsense mutation and three single missense mutations were identified. The missense mutations were located near the motifs common to members of the class I cytokine receptor family. Two of the missense mutations were the same as previously reported in spite of the difference of ethnic backgrounds. The remaining four patients had newly identified mutations.

Our results emphasize the broad molecular heterogeneity of X-linked SCID and suggest the presence of mutational "hot spots" within the IL-2R gamma-chain gene.