A mutation in the promoter region of BTK causes atypical XLA
María Bravo García-Morato,
Lucía del Pino Molina,
Juan Manuel Torres Canizales,
Teresa del Rosal Rabes,
Ana Méndez Echevarría,
Berta González Martínez,
Eduardo López-Granados,
Rebeca Rodríguez Pena
Affiliations
María Bravo García-Morato
Clinical Immunology Department, La Paz University Hospital and Lymphocyte Pathophysiology in Immunodeficiencies Group, La Paz Institute for Health Research (IdiPAZ), Madrid, Spain; Center for Biomedical Network Research on Rare Diseases (CIBERER U767), Madrid, Spain; Corresponding author.
Lucía del Pino Molina
Clinical Immunology Department, La Paz University Hospital and Lymphocyte Pathophysiology in Immunodeficiencies Group, La Paz Institute for Health Research (IdiPAZ), Madrid, Spain; Center for Biomedical Network Research on Rare Diseases (CIBERER U767), Madrid, Spain
Juan Manuel Torres Canizales
Clinical Immunology Department, La Paz University Hospital and Lymphocyte Pathophysiology in Immunodeficiencies Group, La Paz Institute for Health Research (IdiPAZ), Madrid, Spain; Center for Biomedical Network Research on Rare Diseases (CIBERER U767), Madrid, Spain
Teresa del Rosal Rabes
Center for Biomedical Network Research on Rare Diseases (CIBERER U767), Madrid, Spain; Department of Pediatrics, La Paz University Hospital, Madrid, Spain
Ana Méndez Echevarría
Center for Biomedical Network Research on Rare Diseases (CIBERER U767), Madrid, Spain; Department of Pediatrics, La Paz University Hospital, Madrid, Spain
Berta González Martínez
Department of Pediatric Hematology, Oncology, La Paz University Hospital, Madrid, Spain
Eduardo López-Granados
Clinical Immunology Department, La Paz University Hospital and Lymphocyte Pathophysiology in Immunodeficiencies Group, La Paz Institute for Health Research (IdiPAZ), Madrid, Spain; Center for Biomedical Network Research on Rare Diseases (CIBERER U767), Madrid, Spain
Rebeca Rodríguez Pena
Clinical Immunology Department, La Paz University Hospital and Lymphocyte Pathophysiology in Immunodeficiencies Group, La Paz Institute for Health Research (IdiPAZ), Madrid, Spain; Center for Biomedical Network Research on Rare Diseases (CIBERER U767), Madrid, Spain
X-linked Agammaglobulinemia is a primary immunodeficiency caused by mutations in BTK, a tyrosine kinase essential for B lymphocytes differentiation. Patients usually have very low or absent B lymphocytes and are not able to develop humoral specific responses. Here we present a boy, diagnosed with XLA due to a mutation on the promoter region of the gene, whose phenotype is characterised by low percentage of B cells, hypogammaglobulinemia, oscillating neutropenia, antibodies responses to some antigens after vaccination and IgE-mediated allergy. Additional technology as flow cytometry was needed to demonstrate the pathological status of the variant. We focus on the idea that XLA should be suspected in males with B lymphopenia and hypogammaglobulinemia, even if they make humoral specific responses. We also highlight the importance of sequencing BTK's promoter region, as mutations on it can be disease-causing.
