Overview
T-B- severe combined immunodeficiency (SCID) is a very serious inherited condition that affects the immune system. In this form of SCID, both T cells and B cells — two critical types of white blood cells that fight infections — are missing or extremely low. Without these cells, the body cannot defend itself against bacteria, viruses, or fungi. Babies with this condition typically appear healthy at birth but begin developing severe, life-threatening infections within the first few months of life. Common problems include persistent thrush (oral yeast infections), chronic diarrhea, pneumonia, and skin infections that do not respond to standard treatments. Without treatment, this condition is usually fatal within the first one to two years of life. T-B- SCID can be caused by mutations in several different genes, including RAG1, RAG2, DCLRE1C (Artemis), and others involved in the development of both T and B cells. The most well-known subtypes include RAG deficiency and Artemis deficiency. Early diagnosis through newborn screening programs that detect low T cell levels (using the TREC assay) has dramatically improved outcomes. The primary curative treatment is hematopoietic stem cell transplantation (bone marrow transplant), ideally performed before the baby develops serious infections. Gene therapy is also being explored as a treatment option for certain genetic subtypes. Without a transplant or gene therapy, lifelong protective isolation and immunoglobulin replacement therapy are necessary but are not a cure.
Also known as:
Key symptoms:
Severe and recurring infections starting in early infancyPersistent oral thrush that does not clear with treatmentChronic diarrhea and poor weight gainPneumonia or lung infectionsSkin rashes or infectionsFailure to thrive (not growing or gaining weight as expected)Ear infections that keep coming backInfections caused by organisms that usually do not harm healthy people (opportunistic infections)Severe diaper rashAbsence of tonsils or lymph nodes on physical examLife-threatening reaction to live vaccines (such as BCG or rotavirus)Bloodstream infections (sepsis)Persistent fevers
Autosomal recessive
Passed on when both parents carry the same gene change; often skips generations
Neonatal
Begins at or shortly after birth (first 4 weeks)
Treatments
No FDA-approved treatments are currently listed for T-B- severe combined immunodeficiency.
View clinical trials →Clinical Trials
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Rare Disease Specialist
Rare Disease Specialist
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.
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Questions for your doctor
Bring these to your next appointment
- Q1.What specific gene mutation is causing my child's SCID, and how does that affect treatment options?,Is my child a candidate for bone marrow transplant, and what type of donor would be best?,Are there any gene therapy clinical trials available for my child's specific type of SCID?,What infection prevention steps should we take at home right now?,What are the expected outcomes and potential complications of transplant for my child?,Will my child need lifelong immunoglobulin replacement therapy even after transplant?,Should other family members be tested as carriers, and what does this mean for future pregnancies?
Common questions about T-B- severe combined immunodeficiency
What is T-B- severe combined immunodeficiency?
T-B- severe combined immunodeficiency (SCID) is a very serious inherited condition that affects the immune system. In this form of SCID, both T cells and B cells — two critical types of white blood cells that fight infections — are missing or extremely low. Without these cells, the body cannot defend itself against bacteria, viruses, or fungi. Babies with this condition typically appear healthy at birth but begin developing severe, life-threatening infections within the first few months of life. Common problems include persistent thrush (oral yeast infections), chronic diarrhea, pneumonia, and
How is T-B- severe combined immunodeficiency inherited?
T-B- severe combined immunodeficiency 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 typically begin?
Typical onset of T-B- severe combined immunodeficiency is neonatal. Age of onset can vary across affected individuals.
Which specialists treat T-B- severe combined immunodeficiency?
5 specialists and care centers treating T-B- severe combined immunodeficiency are listed on UniteRare, sourced from ClinicalTrials.gov principal investigators, published research, and the NPPES NPI registry.