RecruitingNCT06092346
Immune
Adenosine Deaminase Deficiency
Also known as ADA-SCID, ADA deficiency, adenosine deaminase SCID
Adenosine Deaminase Deficiency is an autosomal recessive disorder of purine metabolism caused by ADA enzyme deficiency, leading to accumulation of deoxyadenosine and its toxic metabolites that selectively destroy T, B, and NK lymphocytes, r
ORPHA:277 ↗Gene ADAPrevalence 1 in 200,000-1,000,000Onset Neonatal to infancy (classic); late-onset forms in adulthoodCombined primary immunodeficiency (metabolic)
1
studies recruiting now
as of 7 Sept 2026
32
studies registered in total
as of 7 Sept 2026
1
countries with a recruiting site
as of 7 Sept 2026
23 Oct 2023
most recent study posted
among recruiting studies
Recruiting trials
Showing the 1 most recently updated recruiting study, as recorded 7 Sept 2026. Live status on each study page.
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About Adenosine Deaminase Deficiency
Adenosine Deaminase Deficiency is an autosomal recessive disorder of purine metabolism caused by ADA enzyme deficiency, leading to accumulation of deoxyadenosine and its toxic metabolites that selectively destroy T, B, and NK lymphocytes, resulting in severe combined immunodeficiency. ADA-SCID was the first disease treated with gene therapy and remains a paradigm for ex vivo lentiviral stem cell gene correction, with licensed therapy (Strimvelis) available in Europe. Enzyme replacement therapy with pegylated ADA (elapegademase) provides a bridging option that partially restores immune function without curative intent.
Common clinical features
Recurrent severe infections beginning in infancyAbsent T, B, and NK cells on lymphocyte phenotypingFailure to thriveSkeletal abnormalities (cupping and flaring of ribs, platyspondyly)Pulmonary alveolar proteinosisNeurological features (spasticity, nystagmus in late-onset)Elevated urinary deoxyadenosine and dATP in erythrocytes
From Orphanet’s phenotype annotations (CC BY 4.0). Not a complete list.
Before you apply
Things trial teams commonly ask about for Adenosine Deaminase Deficiency. Not eligibility rules; those are set by each study.
- Confirm ADA enzyme activity level in erythrocytes or lymphocytes and ADA2 mutation status before applying; distinguish ADA1 deficiency (immune) from ADA2 deficiency (vasculopathy) as trials target them separately
- Gene therapy trial eligibility typically requires absence of a matched sibling donor and no prior allogeneic transplant; transplant history must be disclosed at screening
- Enzyme replacement therapy (ERT) washout period is required for some gene therapy trials; discuss ERT discontinuation risks and timing with your trial coordinator well in advance
Related conditions
Information, not medical advice. Trial listings are shown as recorded on ClinicalTrials.gov; whether any study is right for you is a decision for you and your clinicians, and eligibility is decided by each research team. Disease information from Orphanet (CC BY 4.0).