biostudies-literatureCirillo ETelethon1908https://www.ebi.ac.uk/biostudies/studies/S-EPMC6700292biostudies-literatureUnknown10Severe combined immunodeficiencies (SCIDs) are a group of inborn errors of the immune system, usually associated with severe or life-threatening infections. Due to the variability of clinical phenotypes, the diagnostic complexity and the heterogeneity of the genetic basis, they are often difficult to recognize, leading to a significant diagnostic delay (DD). Aim of this study is to define presenting signs and natural history of SCID in a large cohort of patients, prior to hematopoietic stem cell or gene therapies. To this purpose, we conducted a 30-year retro-prospective multicenter study within the Italian Primary Immunodeficiency Network. One hundred eleven patients, diagnosed as typical or atypical SCID according to the European Society for Immune Deficiencies criteria, were included. PFrontiers in immunologyClinical, Immunological, and Molecular Features of Typical and Atypical Severe Combined Immunodeficiency: Report of the Italian Primary Immunodeficiency Network.PMC6700292TGT16S01Prencipe RSpecchia FLougaris VMontin DGiardino GDi Matteo GRicci SBarzaghi FPession ALocatelli FAiuti APutti MCRossi PPignata CMartire BEsposito FPlebani AScarselli AGiliani SPierani PQuaremba GTommasini ANaviglio SFinocchi AAttardi ECirillo EMarzollo AConsolini RBadolato RCicalese MPGrasso FAzzari CD'Alba ICancrini CMartino SfalseClinical, Immunological, and Molecular Features of Typical and Atypical Severe Combined Immunodeficiency: Report of the Italian Primary Immunodeficiency Network.Severe combined immunodeficiencies (SCIDs) are a group of inborn errors of the immune system, usually associated with severe or life-threatening infections. Due to the variability of clinical phenotypes, the diagnostic complexity and the heterogeneity of the genetic basis, they are often difficult to recognize, leading to a significant diagnostic delay (DD). Aim of this study is to define presenting signs and natural history of SCID in a large cohort of patients, prior to hematopoietic stem cell or gene therapies. To this purpose, we conducted a 30-year retro-prospective multicenter study within the Italian Primary Immunodeficiency Network. One hundred eleven patients, diagnosed as typical or atypical SCID according to the European Society for Immune Deficiencies criteria, were included. P2019-01-01T00:00:00Z20192025-05-31T22:39:57.172Z2025-05-31T22:39:57.172ZS-EPMC67002923145680510.3389/fimmu.2019.01908