MUTATION ANALYSIS BY A NONRADIOACTIVE SINGLE-STRAND CONFORMATION POLYMORPHISM ASSAY IN 9 FAMILIES WITH X-LINKED SEVERE COMBINED IMMUNODEFICIENCY (SCIDX1)

X-linked severe combined immunodeficiency (SCIDX1) is an inherited dis ease characterized by profound abnormalities of cell-mediated and humo ral immunity. Patients with SCIDX1 have defects in the common cytokine receptor gamma chain gene (IL2RG) that encodes a shared, essential co mponent of the receptors for interleukin-2 (IL-2), II-4, IL-7, IL-9 an d IL-15. We have characterized nine SCIDX1 families by using a DNA-bas ed, non-radioactive screening method and DNA sequencing. Nine differen t mutations were found, scattered from exon 1 to exon 5 of the IL2RG g ene. Two of these mutations have been previously identified in other u nrelated patients. the other seven are novel mutations that differ fro m all of the 95 already reported in the IL2RG mutation data base. In a ddition to describing novel mutations in the IL2RG gene, this study sh ows that the knowledge of the genetic defect and the use of an efficie nt, non-radioactive, and rapid screening approach have important impli cations for prenatal and postnatal diagnosis, carrier female identific ation, and possibly prenatal therapy.