IL2RG hypomorphic mutation: identification of a novel pathogenic mutation in exon 8 and a review of the literature

• Main Authors: Che Kang Lim, Hassan Abolhassani, Sofia K. Appelberg, Mikael Sundin, Lennart Hammarström
• Format: Article
• Language: English
• Published: BMC 2019-01-01
• Series: Allergy, Asthma & Clinical Immunology
• Subjects: Interleukin 2 receptor gamma; Atypical severe combined immunodeficiency; Hypomorphic mutations
• Online Access: http://link.springer.com/article/10.1186/s13223-018-0317-y
• ISSN: 1710-1492

Abstract Background Atypical X-linked severe combined immunodeficiency (X-SCID) is a variant of cellular immunodeficiency due to hypomorphic mutations in the interleukin 2 receptor gamma (IL2RG) gene. Due to a leaky clinical phenotype, diagnosis and appropriate treatment are challenging in these patients. Case presentation We report a 16-year-old patient with a Tlow B+ NK+ cellular immunodeficiency due to a novel nonsense mutation in exon 8 (p.R328X) of the IL2RG gene. Functional impairment of the IL2RG was confirmed by IL2-Janus kinase 3-signal transducer and activator of transcription signaling pathway investigation. In addition, the characteristics of the mutations previously described in 39 patients with an atypical phenotype were reviewed and analyzed from the literature. Conclusion This is the first report of an atypical X-SCID phenotype due to an exon 8 mutation in the IL2RG gene. The variability in the phenotypic spectrum of classic X-SCID associated gene highlights the necessity of multi-disciplinary cooperation vigilance for a more accurate diagnostic workup.