Heterozygous FOXN1 Variants Cause Low TRECs and Severe T Cell Lymphopenia, Revealing a Crucial Role of FOXN1 in Supporting Early Thymopoiesis

    September 2019 in “ American journal of human genetics ”
    Marita Bosticardo, Yasuhiro Yamazaki, Jennifer E. Cowan, Giuliana Giardino, Cristina Corsino, Giulia Scalia, Rosaria Prencipe, Melanie A. Ruffner, David R.C. Hill, Inga Sakovich, Irma Yemialyanava, Jonathan S. Tam, Nurcicek Padem, Melissa E. Elder, John W. Sleasman, Elena Pérez, Hana Niebur, Christine M. Seroogy, Svetlana O. Sharapova, Jennifer Gebbia, Gary Kleiner, Jane Peake, Jordan K. Abbott, Erwin W. Gelfand, Elena Crestani, Catherine M. Biggs, Manish J. Butte, Nicholas Hartog, Anthony R. Hayward, Karin Chen, Jennifer Heimall, Filiz O. Seeborg, Lisa M. Bartnikas, Megan A. Cooper, Claudio Pignata, Avinash Bhandoola, Luigi D. Notarangelo
    Image of study
    TLDR FOXN1 gene variants cause low T cells and immune issues from birth.
    The study identified that heterozygous loss-of-function variants in the FOXN1 gene caused low levels of T cell receptor excision circles (TRECs) and severe T cell lymphopenia in newborns, often accompanied by nail dystrophy. Longitudinal analysis revealed persistent T cell lymphopenia during infancy and lower CD8+ cell counts in adults with these variants. The researchers hypothesized a gene dosage effect of FOXN1 on thymic epithelial cells (TECs) and thymopoiesis, which was more pronounced early in life. In Foxn1nu/+ mice, there was a significant reduction in early thymic progenitor (ETP) cells and delayed maturation of the medullary TEC compartment, along with reduced expression of FOXN1 target genes. These findings established that FOXN1 haploinsufficiency is a crucial genetic factor for T cell lymphopenia at birth.
    Discuss this study in the Community →

    Cited in this study

    5 / 5 results