Severe combined immunodeficiency (SCID) represents a rare group of primary immunodeficiency disorders (PIDs), with known or unknown genetic alterations. Here, we report a new interleukin 2 receptor, gamma chain (IL-2RG) mutation in an Iranian SCID newborn. The patient was a 6-day old boy with a family history of PID. The child was screened using a molecular-based analysis for the assessment of T cell receptor excision circles (TRECs) and kappa-deleting recombination excision circles (KRECs). Moreover, a complete immunological evaluation and gene sequencing was performed. Results showed undetectable TREC but a high level of KREC copy numbers. Flow cytometric data indicated low numbers of T and NK cells, but elevated number of B cells. A novel substitution in IL2RG: c.675 C>A, leading to p.225 Ser>Arg was found. Based on the functional analysis, the mutation is predicted to be damaging. The patient was diagnosed as a T B+ NK X-linked SCID.
Keywords: Interleukin-2 Receptor gamma Chain; Severe Combined Immune Deficiency; T-cell receptor excision circles; kappa-deleting recombination excision circles.