Zahra Shahbazi1, Reza Yazdani2, Sepideh Shahkarami3, Shirin Shahbazi4, Mohammad Hamid1, Mahnaz Sadeghi-Shabestari5, Tooba Momen6, Soheila Aleyasin7, Hossein Esmaeilzadeh7, Sepideh Darougar8, Sama Delavari2, Seyed Alireza Mahdaviani9, Hamid Ahanchian10, Fatemeh Behmanesh7, Fatemeh Kiaee11, Zahra Chavoshzade12, Mansoureh Shariat13, Mohammad Keramatipour14, Nima Rezaei2, Hassan Abolhassani2, Nima Parvaneh2, Reza Mahdian15, Asghar Aghamohammadi16. 1. Molecular Medicine Department, Biotechnology Research Center, Pasteur Institute of Iran, Tehran 1316943551, Iran. 2. Research Center for Immunodeficiencies, Pediatrics Center of Excellence, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran. 3. Medical Genetics Network (MeGeNe), Universal Scientific Education and Research Network (USERN), Tehran, Iran. 4. Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran. 5. Immunology research center of Tabriz, TB and lung research center of Tabriz, Tabriz university of medical science, Tabriz, Iran. 6. Department of Allergy and Clinical Immunology, Child Growth and Development Research Center, Research Institute for Primordial Prevention of Non-Communicable Disease, Isfahan University of Medical Sciences, Isfahan, Iran. 7. Allergy Research Center, Shiraz University of Medical Sciences, Shiraz, Iran. 8. Department of Pediatrics, Tehran Medical Sciences Branch, Islamic Azad University, Tehran, Iran. 9. Pediatric Respiratory Diseases Research Center, National Research Institute of Tuberculosis and Lung Diseases (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran. 10. Allergy Research Center, Mashhad University of Medical Sciences, Mashhad, Iran. 11. Department of Immunology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran. 12. Pediatric Infections Research Center, Mofid Children's Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran. 13. Department of Allergy and Clinical Immunology, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran. 14. Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. 15. Molecular Medicine Department, Biotechnology Research Center, Pasteur Institute of Iran, Tehran 1316943551, Iran. Electronic address: mahdian@pasteur.ac.ir. 16. Research Center for Immunodeficiencies, Pediatrics Center of Excellence, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran. Electronic address: aghamohammadi@tums.ac.ir.
Abstract
BACKGROUND: Severe combined immunodeficiency (SCID) is the most severe form of primary immunodeficiency disorders that is characterized by impaired early T lymphocyte differentiation and is variably associated with abnormal development of other lymphocyte lineages. SCID can be caused by mutations in more than 20 different genes. Molecular diagnosis in SCID patients contributes to genetic counseling, prenatal diagnosis, treatment modalities, and overall prognosis. In this cohort, the clinical, laboratory and genetic data related to Iranian SCID patients were comprehensively evaluated and efficiency of stepwise sequencing methods approach based on immunophenotype grouping was investigated METHODS: Clinical and laboratory data from 242 patients with SCID phenotype were evaluated. Molecular genetic analysis methods including Sanger sequencing, targeted gene panel and whole exome sequencing were performed on 62 patients. RESULTS: Mortality rate was 78.9% in the cohort with a median follow-up of four months. The majority of the patients had a phenotype of T-NK-B+ (34.3%) and the most severe clinical manifestation and highest mortality rate were observed in T-NK-B- SCID cases. Genetic mutations were confirmed in 50 patients (80.6%), of which defects in recombination-activating genes (RAG1 and RAG2) were found in 16 patients (32.0%). The lowest level of CD4+ and CD8+ cells were observed in patients with ADA deficiency (p = 0.026) and IL2RG deficiency (p = 0.019), respectively. CONCLUSION: Current findings suggest that candidate gene approach based on patient's immunophenotype might accelerate molecular diagnosis of SCID patients. Candidate gene selection should be done according to the frequency of disease-causing genes in different populations. Targeted gene panel, WES and WGS methods can be used for the cases which are not diagnosed using this method.
BACKGROUND: Severe combined immunodeficiency (SCID) is the most severe form of primary immunodeficiency disorders that is characterized by impaired early T lymphocyte differentiation and is variably associated with abnormal development of other lymphocyte lineages. SCID can be caused by mutations in more than 20 different genes. Molecular diagnosis in SCIDpatients contributes to genetic counseling, prenatal diagnosis, treatment modalities, and overall prognosis. In this cohort, the clinical, laboratory and genetic data related to Iranian SCIDpatients were comprehensively evaluated and efficiency of stepwise sequencing methods approach based on immunophenotype grouping was investigated METHODS: Clinical and laboratory data from 242 patients with SCID phenotype were evaluated. Molecular genetic analysis methods including Sanger sequencing, targeted gene panel and whole exome sequencing were performed on 62 patients. RESULTS:Mortality rate was 78.9% in the cohort with a median follow-up of four months. The majority of the patients had a phenotype of T-NK-B+ (34.3%) and the most severe clinical manifestation and highest mortality rate were observed in T-NK-B- SCID cases. Genetic mutations were confirmed in 50 patients (80.6%), of which defects in recombination-activating genes (RAG1 and RAG2) were found in 16 patients (32.0%). The lowest level of CD4+ and CD8+ cells were observed in patients with ADA deficiency (p = 0.026) and IL2RG deficiency (p = 0.019), respectively. CONCLUSION: Current findings suggest that candidate gene approach based on patient's immunophenotype might accelerate molecular diagnosis of SCIDpatients. Candidate gene selection should be done according to the frequency of disease-causing genes in different populations. Targeted gene panel, WES and WGS methods can be used for the cases which are not diagnosed using this method.
Authors: R El Hawary; S Meshaal; J Pachlopnik Schmid; A Elmarsafy; A A Mauracher; L Opitz; D Abd Elaziz; S Lotfy; A Eldash; J Boutros; N Galal Journal: Clin Exp Immunol Date: 2020-11-02 Impact factor: 5.732