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Severe combined immunodeficiency (SCID) has a diverse genetic aetiology, where a clinical phenotype, caused by single and/or multiple gene variants, can give rise to multiple presentations. The advent of next-generation sequencing (NGS) has recently enabled rapid identification of the molecular aetiology of SCID, which is crucial for prognosis and treatment strategies. We sought to identify the genetic aetiology of various phenotypes of SCIDs and assessed both clinical and immunologic characteristics associated with gene variants. An amplicon-based targeted NGS panel, which contained 18 most common SCID-related genes, was contumely made to screen the patients (n = 38) with typical SCID, atypical SCID or OMENN syndrome. Allelic segregations were confirmed for the detected gene variants within the families. In total, 24 disease-causing variants (17 known and 7 novel) were identified in 23 patients in 9 different SCID genes: RAG1 (n = 5), RAG2 (n = 2), ADA (n = 3), DCLRE1C (n = 2), NHEJ1 (n = 2), CD3E (n = 2), IL2RG (n = 3), JAK3 (n = 4) and IL7R (n = 1). The overall success rate of our custom-made NGS panel was 60% (39.3% for NK+ SCID and 100% for NK- SCID). Incidence of autosomal-recessive inherited genes is more frequently found in our cohort than the previously reported populations probably due to the high consanguineous marriages in Turkey. In conclusion, the custom-made sequencing panel was able to identify and confirm the previously known and novel disease-causing variants with high accuracy. Istanbul Bilgi UniversityIstanbul Bilgi University [NGYY-2018.01.0006]; Bilimsel Arastirma Projeleri Birimi, Istanbul Universitesi [52575, 20499] Istanbul Bilgi University, Grant/Award Number: NGYY-2018.01.0006; Bilimsel Arastirma Projeleri Birimi, Istanbul Universitesi, Grant/Award Number: 52575 and 20499 WOS:000534741000001 32445296 Q4

Primary antibody deficiencies (PAD) are the most common subtype of primary immunodeficiencies, characterized by increased susceptibility to infections and autoimmunity, allergy, or malignancy predisposition. PAD syndromes comprise of immune system genes highlighted the key role of B cell activation, proliferation, migration, somatic hypermutation, or isotype switching have a wide spectrum from agammaglobulinemia to selective Ig deficiency. In this study, we describe the molecular and the clinical aspects of fifty-two PAD patients. The most common symptoms of our cohort were upper and lower respiratory infections, bronchiectasis, diarrhea, and recurrent fever. Almost all patients (98%) had at least one of the symptoms like autoimmunity, lymphoproliferation, allergy, or gastrointestinal disease. A custom-made next-generation sequencing (NGS) panel, which contains 24 genes, was designed to identify well-known disease-causing variants in our cohort. We identified eight variants (15.4%) among 52 PAD patients. The variants mapped to BTK (n = 4), CD40L (n = 1), ICOS (n = 1), IGHM (n = 1), and TCF3 (n = 1) genes. Three novel variants were described in the BTK (p.G414W), ICOS (p.G60*), and IGHM (p.S19*) genes. We performed Sanger sequencing to validate pathogenic variants and check for allelic segregation in the family. Targeted NGS panel sequencing can be beneficial as a suitable diagnostic modality for diagnosing well-known monogenic PAD diseases (only 2-10% of PADs); however, screening only the coding regions of the genome may not be adequately powered to solve the pathogenesis of PAD in all cases. Deciphering the regulatory regions of the genome and better understanding the epigenetic modifications will elucidate the molecular basis of complex PADs. Istanbul University ; Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) ; Istanbul Bilgi University

Introduction: The lymphoid enhancer factor 1 (LEF1) is a DNA-binding transcription factor that functions in the Wnt signaling pathway. Increased LEF1 activity is associated with progression of several types of cancer including leukemia. Here, we investigated LEF1 isoform expression and genomic variations in acute lymphoblastic leukemia (ALL). Methods: LEF1 isoform expression was evaluated by quantitative real-time PCR in 87 newly diagnosed childhood ALL patients and controls. Moreover, Western blot analysis was performed for detection of LEF1 expression and the hotspot region of LEF1 was screened by deep sequencing. Results: The LEF1 mRNA expression of B cell ALL patients was higher than the controls (LEF1-total P = .011, LEF1-long P = .026). Moreover, B-ALL samples showing higher total LEF1 expression had significantly shorter relapse-free survival (P = .008) and overall survival (P = .011). Although full-length LEF1 expression was similar to the controls in T-ALL, 50% (n = 15) of the ALL patients had increased full-length LEF1 protein expression. Imbalance between short- and full-length LEF1 isoforms may lead to cell survival in ALL. Beside the LEF1 activation, LEF1 gene variations were rarely observed in our cohort. Conclusion: The results indicate that the Wnt pathway may have a pathogenic function in a group of ALL patients and high LEF1-total expression might be a marker for shorter relapse-free survival time in B cell ALL. WOS:000639287900001 33844466 Q3

The original published version of this article contained a mistake in one of the affiliations. The correct affiliation of author Manolya Kara (7) should read: Istinye University Faculty of Medicine, VM MedicalPark Pendik Hospital, Pediatric Infectious Diseases Clinic, Istanbul, Turkey The original article has been corrected. © 2021, Springer Science+Business Media, LLC, part of Springer Nature. 10.1007/s12026-021-09248-7 WOS:000708817100001 34668146 Q3

Baris, Safa/0000-0002-4730-9422; kiykim, ayca/0000-0001-5821-3963; FIRTINA, Sinem/0000-0002-3370-8545; Ozen, Ahmet/0000-0002-9065-1901; NG, YUK YIN/0000-0001-9755-6045 Severe combined immunodeficiency (SCID) is the most severe form of primary immunodeficiencies (PIDs) caused by gene variants that lead to a failure of functional T cell development, with or without accompanying defects in the production of B and/or NK cells Istanbul University Research FundIstanbul University [52575, 20499] This project is supported by Istanbul University Research Fund (No: 52575 and 20499) and Istanbul Bilgi University [Y.Y Ng, 2017)]. WOS: 000463216500006 30903456 Q1