Overview
T-B+ severe combined immunodeficiency due to JAK3 deficiency (also called JAK3-SCID or JAK3-deficient SCID) is a rare and serious disorder of the immune system. In this condition, the body cannot make enough working T cells — the white blood cells that fight infections and coordinate the immune response. B cells are present in normal or even high numbers, but they do not work properly because they depend on T cells to function. Natural killer (NK) cells are also absent or very low. This pattern is called 'T-B+ SCID' because T cells are missing (T-) while B cells are present (B+). The disease is caused by changes (mutations) in the JAK3 gene, which provides instructions for making a protein that immune cells need to grow and survive. Without working JAK3 protein, the immune system cannot develop normally, leaving babies almost completely defenseless against infections. Babies with JAK3-SCID typically become very sick in the first months of life with severe, repeated, or unusual infections — including infections that would not normally cause serious illness in healthy children. Without treatment, this condition is life-threatening. The main curative treatment is a bone marrow transplant (also called a hematopoietic stem cell transplant), which can restore a working immune system. Gene therapy is also being studied as a future option.
Also known as:
Key symptoms:
Severe, repeated bacterial infectionsSerious viral infections that healthy children handle easilyFungal infections such as thrush (Candida) that keep coming backPneumonia, especially from a germ called Pneumocystis jiroveciiFailure to gain weight and grow normally (failure to thrive)Chronic diarrheaSkin rashesSwollen lymph nodes or, unusually, very small or absent lymph nodesInfections that do not get better with standard treatmentReactions to live vaccines (such as BCG or rotavirus) that cause serious illnessVery low or absent T cells and NK cells on blood testsB cells present but not working properly
Clinical phenotype terms (25)— hover any for plain English
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 JAK3 deficiency.
View clinical trials →Clinical Trials
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Specialists
View all specialists →No specialists are currently listed for T-B+ severe combined immunodeficiency due to JAK3 deficiency.
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 JAK3 deficiency.
Community
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Caregiver Resources
NORD Caregiver Resources
Support, advocacy, and financial assistance for caregivers of rare disease patients.
Mental Health Support
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Family & Caregiver Grants
Financial assistance programs specifically for caregivers of rare disease patients.
Social Security Disability
Learn how rare disease patients may qualify for SSDI/SSI benefits.
Questions for your doctor
Bring these to your next appointment
- Q1.Is my child a candidate for a bone marrow transplant, and how soon should it happen?,What type of donor is best for my child, and how do we find one?,What infections should I watch for, and when should I go to the emergency room?,Which vaccines are safe for my child and for other people in our household?,Are there any clinical trials for gene therapy that my child might qualify for?,What does immune recovery look like after transplant, and how will we monitor it?,Should other family members be tested to see if they are carriers of the JAK3 mutation?
Common questions about T-B+ severe combined immunodeficiency due to JAK3 deficiency
What is T-B+ severe combined immunodeficiency due to JAK3 deficiency?
T-B+ severe combined immunodeficiency due to JAK3 deficiency (also called JAK3-SCID or JAK3-deficient SCID) is a rare and serious disorder of the immune system. In this condition, the body cannot make enough working T cells — the white blood cells that fight infections and coordinate the immune response. B cells are present in normal or even high numbers, but they do not work properly because they depend on T cells to function. Natural killer (NK) cells are also absent or very low. This pattern is called 'T-B+ SCID' because T cells are missing (T-) while B cells are present (B+). The disease
How is T-B+ severe combined immunodeficiency due to JAK3 deficiency inherited?
T-B+ severe combined immunodeficiency due to JAK3 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 JAK3 deficiency typically begin?
Typical onset of T-B+ severe combined immunodeficiency due to JAK3 deficiency is infantile. Age of onset can vary across affected individuals.