Overview
Severe combined immunodeficiency due to adenosine deaminase deficiency, often called ADA-SCID or ADA deficiency, is a rare and serious inherited disease that severely weakens the immune system. It is caused by a missing or non-working enzyme called adenosine deaminase (ADA). Without this enzyme, toxic substances build up inside immune cells called T cells, B cells, and NK cells, destroying them. This leaves the body almost completely unable to fight infections. Babies born with ADA-SCID typically appear healthy at birth but begin getting very sick within the first few months of life. They suffer from repeated, severe infections caused by bacteria, viruses, and fungi that a healthy immune system would normally handle easily. Without treatment, ADA-SCID is life-threatening in early childhood. The good news is that treatment options have improved greatly. A bone marrow transplant (also called a stem cell transplant) from a matched donor can be curative. Enzyme replacement therapy using a drug called pegademase bovine (Adagen) can help manage the disease. Most excitingly, ADA-SCID was one of the first diseases successfully treated with gene therapy. A gene therapy product called Strimvelis is approved in Europe, and another called Lenmeldy (OTL-101) has received FDA approval in the United States, offering the possibility of a long-term cure.
Also known as:
Key symptoms:
Repeated and severe infections starting in early infancyInfections that do not respond well to standard antibiotics or antifungalsPneumonia, especially from a germ called Pneumocystis jiroveciiChronic diarrheaFailure to gain weight and grow normally (failure to thrive)Skin rashes or infectionsOral thrush (fungal infection in the mouth)Ear infections that keep coming backVery low levels of infection-fighting white blood cells (lymphopenia)Enlarged lymph nodes or absent lymph nodesBone abnormalities visible on X-rayNeurological problems such as developmental delays in some patientsHearing loss in some patients
Clinical phenotype terms (20)— 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 Severe combined immunodeficiency due to adenosine deaminase deficiency.
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Rare Disease Specialist
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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 Severe combined immunodeficiency due to adenosine deaminase deficiency.
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Questions for your doctor
Bring these to your next appointment
- Q1.Which treatment option — gene therapy, bone marrow transplant, or enzyme replacement — is best for my child, and why?,Is my child eligible for gene therapy, and where is it available?,What infections should I be most worried about, and what precautions should I take at home?,Are there any vaccines my child should absolutely not receive?,What does long-term follow-up look like after treatment, and what complications should we watch for?,Should other family members be tested to see if they are carriers?,What support services or patient organizations can help our family?
Common questions about Severe combined immunodeficiency due to adenosine deaminase deficiency
What is Severe combined immunodeficiency due to adenosine deaminase deficiency?
Severe combined immunodeficiency due to adenosine deaminase deficiency, often called ADA-SCID or ADA deficiency, is a rare and serious inherited disease that severely weakens the immune system. It is caused by a missing or non-working enzyme called adenosine deaminase (ADA). Without this enzyme, toxic substances build up inside immune cells called T cells, B cells, and NK cells, destroying them. This leaves the body almost completely unable to fight infections. Babies born with ADA-SCID typically appear healthy at birth but begin getting very sick within the first few months of life. They suf
How is Severe combined immunodeficiency due to adenosine deaminase deficiency inherited?
Severe combined immunodeficiency due to adenosine deaminase deficiency follows a autosomal recessive inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does Severe combined immunodeficiency due to adenosine deaminase deficiency typically begin?
Typical onset of Severe combined immunodeficiency due to adenosine deaminase deficiency is infantile. Age of onset can vary across affected individuals.
Which specialists treat Severe combined immunodeficiency due to adenosine deaminase deficiency?
12 specialists and care centers treating Severe combined immunodeficiency due to adenosine deaminase deficiency are listed on UniteRare, sourced from ClinicalTrials.gov principal investigators, published research, and the NPPES NPI registry.