Tehran University of Medical Sciences Iranian Journal of Allergy, Asthma and Immunology 1735-1502 19 1 2020 02 01 94 101 Taravat Talebi Department of Genetics and Molecular Medicine, School of Medicine, Zanjan University of Medical Sciences (ZUMS), Zanjan, Iran Alireza Biglari Department of Genetics and Molecular Medicine, School of Medicine, Zanjan University of Medical Sciences (ZUMS), Zanjan, Iran Mohammad Shahroeei Clinical and Diagnostic Immunology, Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium AND Specialised Immunology Laboratory of Dr. Shahrooei, Ahvaz, Iran Majid Changi-Ashtiani School of Mathematics, Institute for Research in Fundamental Sciences (IPM), Tehran, Iran Hossein Dinmohammadi Department of Genetics and Molecular Medicine, School of Medicine, Zanjan University of Medical Sciences (ZUMS), Zanjan, Iran Shadi Sadat Navabi Specialised Immunology Laboratory of Dr. Shahrooei, Ahvaz, Iran Nima Parvaneh Department of Pediatrics, Division of Allergy and Clinical Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran Xavier Bossuyt Clinical and Diagnostic Immunology, Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium AND Department of Laboratory Medicine, University Hospitals Leuven, Leuven, Belgium Tina Shahani Department of Genetics and Molecular Medicine, School of Medicine, Zanjan University of Medical Sciences (ZUMS), Zanjan, Iran Hassan Rokni-Zadeh Department of Medical Biotechnology, School of Medicine, Zanjan University of Medical Sciences (ZUMS), Zanjan, Iran 2019 04 10 2019 08 14 Severe combined immunodeficiency (SCID) comprises a heterogeneous group of genetic disorders caused by early defects in the development and function of T cells. Other lymphocyte lineages (B and/or natural killer cells) are variably affected. With a worldwide frequency of approximately 1:50,000 live births, SCID may result from diverse mutations in over 16 genes. Whole-exome sequencing (WES) provides an opportunity for parallel screening of all those genes. This approach is also useful for genetic diagnosis in parents whose infant expired before genetic testing. Here, we describe a heterozygous novel non-frameshift deletion (c.587_598del p.196_199del) in the adenosine deaminase (ADA) gene identified by WES in healthy parents of an expired child with SCID. The mutation was subsequently confirmed to be homozygous in the deceased baby whose left-over blood sample volume was insufficient for direct WES analysis. In conclusion, we here describe a novel mutation in ADA, a well-known SCID gene. https://ijaai.tums.ac.ir/index.php/ijaai/article/view/2364