TY - JOUR
T1 - Asymptomatic Infant With Atypical SCID and Novel Hypomorphic RAG Variant Identified by Newborn Screening
T2 - A Diagnostic and Treatment Dilemma
AU - Chitty-Lopez, Maria
AU - Westermann-Clark, Emma
AU - Dawson, Irina
AU - Ujhazi, Boglarka
AU - Csomos, Krisztian
AU - Dobbs, Kerry
AU - Le, Khuong
AU - Yamazaki, Yasuhiro
AU - Sadighi Akha, Amir A.
AU - Chellapandian, Deepak
AU - Oshrine, Ben
AU - Notarangelo, Luigi D.
AU - Sunkersett, Gauri
AU - Leiding, Jennifer W.
AU - Walter, Jolan E.
N1 - Funding Information:
Maryssa Ellison for help as research coordinator, Dr. Joseph Dasso for grammar review, Dr. Attila Kumanovics for help with laboratory interpretation, Carla Duff and Jessica Trotter for coordination of care with the Florida State Newborn Screening Program. Funding. This work was supported by the National Institutes of Health (sub-R01AI100887-05 to JW), Robert A. Good Endowment, University of South Florida (to JW), Jeffrey Modell Foundation (to JW), and by the Division of Intramural Research, National Institute of Allergy and Infectious Diseases (to LN).
Funding Information:
This work was supported by the National Institutes of Health (sub-R01AI100887-05 to JW), Robert A. Good Endowment, University of South Florida (to JW), Jeffrey Modell Foundation (to JW), and by the Division of Intramural Research, National Institute of Allergy and Infectious Diseases (to LN).
Publisher Copyright:
© Copyright © 2020 Chitty-Lopez, Westermann-Clark, Dawson, Ujhazi, Csomos, Dobbs, Le, Yamazaki, Sadighi Akha, Chellapandian, Oshrine, Notarangelo, Sunkersett, Leiding and Walter.
PY - 2020/9/29
Y1 - 2020/9/29
N2 - The T-cell receptor excision circle (TREC) assay detects T-cell lymphopenia (TCL) in newborns and is especially important to identify severe combined immunodeficiency (SCID). A spectrum of SCID variants and non-SCID conditions that present with TCL are being discovered with increasing frequency by newborn screening (NBS). Recombination-activating gene (RAG) deficiency is one the most common causes of classical and atypical SCID and other conditions with immune dysregulation. We present the case of an asymptomatic male with undetectable TRECs on NBS at 1 week of age. The asymptomatic newborn was found to have severe TCL, but normal B cell quantities and lymphocyte proliferation upon mitogen stimulation. Next generation sequencing revealed compound heterozygous hypomorphic RAG variants, one of which was novel. The moderately decreased recombinase activity of the RAG variants (16 and 40%) resulted in abnormal T and B-cell receptor repertoires, decreased fraction of CD3+ TCRVα7.2+ T cells and an immune phenotype consistent with the RAG hypomorphic variants. The patient underwent successful treatment with hematopoietic stem cell transplantation (HSCT) at 5 months of age. This case illustrates how after identification of a novel RAG variant, in vitro studies are important to confirm the pathogenicity of the variant. This confirmation allows the clinician to expedite definitive treatment with HSCT in an asymptomatic phase, mitigating the risk of serious infectious and non-infectious complications.
AB - The T-cell receptor excision circle (TREC) assay detects T-cell lymphopenia (TCL) in newborns and is especially important to identify severe combined immunodeficiency (SCID). A spectrum of SCID variants and non-SCID conditions that present with TCL are being discovered with increasing frequency by newborn screening (NBS). Recombination-activating gene (RAG) deficiency is one the most common causes of classical and atypical SCID and other conditions with immune dysregulation. We present the case of an asymptomatic male with undetectable TRECs on NBS at 1 week of age. The asymptomatic newborn was found to have severe TCL, but normal B cell quantities and lymphocyte proliferation upon mitogen stimulation. Next generation sequencing revealed compound heterozygous hypomorphic RAG variants, one of which was novel. The moderately decreased recombinase activity of the RAG variants (16 and 40%) resulted in abnormal T and B-cell receptor repertoires, decreased fraction of CD3+ TCRVα7.2+ T cells and an immune phenotype consistent with the RAG hypomorphic variants. The patient underwent successful treatment with hematopoietic stem cell transplantation (HSCT) at 5 months of age. This case illustrates how after identification of a novel RAG variant, in vitro studies are important to confirm the pathogenicity of the variant. This confirmation allows the clinician to expedite definitive treatment with HSCT in an asymptomatic phase, mitigating the risk of serious infectious and non-infectious complications.
KW - HSCT
KW - SCID
KW - asymptomatic infant
KW - immunodeficiency
KW - newborn screening
KW - recombinase activating gene (RAG)
UR - http://www.scopus.com/inward/record.url?scp=85092534657&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85092534657&partnerID=8YFLogxK
U2 - 10.3389/fimmu.2020.01954
DO - 10.3389/fimmu.2020.01954
M3 - Article
C2 - 33117328
AN - SCOPUS:85092534657
SN - 1664-3224
VL - 11
JO - Frontiers in immunology
JF - Frontiers in immunology
M1 - 1954
ER -