Overview
T-B+ severe combined immunodeficiency (SCID) due to CD45 deficiency is an extremely rare form of SCID caused by mutations in the PTPRC gene, which encodes the CD45 protein (also known as leukocyte common antigen or protein tyrosine phosphatase receptor type C). CD45 is a transmembrane phosphatase expressed on all nucleated hematopoietic cells and plays a critical role in T-cell and B-cell receptor signaling. Loss of functional CD45 leads to a profound defect in T-cell development and function, while B cells may be present in normal or near-normal numbers but are functionally impaired due to the lack of T-cell help and intrinsic B-cell signaling defects. Affected infants typically present in the first months of life with severe, recurrent, and life-threatening infections, including pneumonia, chronic diarrhea, oral candidiasis, and failure to thrive. The immunological phenotype is characterized by absent or profoundly reduced T cells with the presence of B cells (T-B+ SCID), though natural killer (NK) cell numbers may vary. Without treatment, the condition is fatal in early childhood due to overwhelming infections. The immune system is the primary body system affected, but secondary complications can involve the lungs, gastrointestinal tract, skin, and other organs due to opportunistic infections. The definitive treatment for CD45-deficient SCID is hematopoietic stem cell transplantation (HSCT), which can reconstitute the immune system if performed early, ideally before the onset of severe infections. Newborn screening programs that detect SCID through T-cell receptor excision circle (TREC) assays can identify affected infants before clinical symptoms develop, improving transplant outcomes. Gene therapy is not yet established for this specific form of SCID. Supportive care includes infection prophylaxis, immunoglobulin replacement therapy, and protective isolation until definitive treatment is achieved.
Also known as:
Autosomal recessive
Passed on when both parents carry the same gene change; often skips generations
Infantile
Begins in infancy, roughly 1 month to 2 years old
Treatments
No FDA-approved treatments are currently listed for T-B+ severe combined immunodeficiency due to CD45 deficiency.
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Specialists
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Treatment Centers
8 centersBaylor College of Medicine Rare Disease Center ↗
Baylor College of Medicine
📍 Houston, TX
🏥 NORDStanford Medicine Rare Disease Center ↗
Stanford Medicine
📍 Stanford, CA
🔬 UDNNIH Clinical Center Undiagnosed Diseases Program ↗
National Institutes of Health
📍 Bethesda, MD
🔬 UDNUCLA UDN Clinical Site ↗
UCLA Health
📍 Los Angeles, CA
🔬 UDNBaylor College of Medicine UDN Clinical Site ↗
Baylor College of Medicine
📍 Houston, TX
🔬 UDNHarvard/MGH UDN Clinical Site ↗
Massachusetts General Hospital
📍 Boston, MA
🏥 NORDMayo Clinic Center for Individualized Medicine ↗
Mayo Clinic
📍 Rochester, MN
👤 Mayo Clinic Center for Individualized Medicine
🏥 NORDUCLA Rare Disease Day Program ↗
UCLA Health
📍 Los Angeles, CA
Travel Grants
No travel grants are currently matched to T-B+ severe combined immunodeficiency due to CD45 deficiency.
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Common questions about T-B+ severe combined immunodeficiency due to CD45 deficiency
What is T-B+ severe combined immunodeficiency due to CD45 deficiency?
T-B+ severe combined immunodeficiency (SCID) due to CD45 deficiency is an extremely rare form of SCID caused by mutations in the PTPRC gene, which encodes the CD45 protein (also known as leukocyte common antigen or protein tyrosine phosphatase receptor type C). CD45 is a transmembrane phosphatase expressed on all nucleated hematopoietic cells and plays a critical role in T-cell and B-cell receptor signaling. Loss of functional CD45 leads to a profound defect in T-cell development and function, while B cells may be present in normal or near-normal numbers but are functionally impaired due to th
How is T-B+ severe combined immunodeficiency due to CD45 deficiency inherited?
T-B+ severe combined immunodeficiency due to CD45 deficiency follows a autosomal recessive inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does T-B+ severe combined immunodeficiency due to CD45 deficiency typically begin?
Typical onset of T-B+ severe combined immunodeficiency due to CD45 deficiency is infantile. Age of onset can vary across affected individuals.