X-linked severe combined immunodeficiency: from molecular cause to gene therapy within seven years

X-linked severe combined immunodeficiency (XSCID) is the most common form o f SCID, The discovery of the genetic defect in this disease, namely mutatio ns in the gene encoding the common cytokine receptor gamma chain, gamma(c), was reported just over seven years ago. In the subsequent period, a tremen dous amount of knowledge about the biology and function of this protein has been generated. Moreover, gamma(c)-knockout mice have been generated and t heir immune systems successfully reconstituted by gene therapy, Furthermore , initial attempts at using gene therapy to treat patients with XSCID have been successful for more than ten months, making this disease perhaps the m ost promising to date for treatment with such a strategy.