Congenital Athymia Clinical Trials and Treatments

Congenital athymia results from the absence or severe hypoplasia of the thymus, an organ in the upper chest where T lymphocytes mature and undergo selection. Without a functional thymus, the body cannot produce naive T cells, leaving patients profoundly immunodeficient and unable to mount adaptive immune responses against pathogens. The condition is distinct from severe combined immunodeficiency (SCID) in that the underlying defect is in the thymic microenvironment rather than in the hematopoietic stem cells themselves.

The most common symptoms of Congenital Athymia include Recurrent or persistent severe infections beginning in the first months of life, Chronic or recurrent pneumonia, Chronic diarrhea and gastrointestinal infections, Persistent oral thrush or skin yeast infections, Failure to thrive and difficulty gaining weight, among others. Approximately 17 to 24 new cases per year in the U.S.; estimated fewer than 500 living patients. Symptoms can range from mild to severe and may vary between individuals.

Trial Friend lists all active clinical trials for Congenital Athymia from ClinicalTrials.gov, with eligibility criteria translated into plain English. Patients can filter by trial phase and recruitment status, search by location, and use the Match Me tool to score trials against their profile. RETHYMIC is currently the only FDA-approved treatment specifically for congenital athymia, and it represents a fundamentally different approach from conventional transplant by providing the thymic microenvironment needed for T-cell development. If your child has been identified through newborn SCID screening with absent or very low TRECs, prompt evaluation at a center experienced in thymus transplantation is essential.

Yes. As of September 2026, Trial Friend lists 1 FDA-approved drug used to treat Congenital Athymia: Rethymic (allogeneic processed thymus tissue-agdc), first approved in 2021.

Each has its own page with what the label covers, side effects and how it is given, and the Treatments section of this page adds any further approved drugs found in FDA labeling data.

Congenital Athymia is caused by variants in the CHD7, TBX1, FOXN1, PAX1 and FOXI3 genes. Most infants have 22q11.2 deletion syndrome or CHARGE syndrome (CHD7); FOXN1 and PAX1 are rarer causes.

Most cases arise from a new variant not carried by either parent, so the chance of it recurring in a sibling is low but not zero. Approximately 17 to 24 new cases per year in the U.S.; estimated fewer than 500 living patients. Genetic testing confirms the diagnosis.

Yes. Genetic testing for Congenital Athymia looks at the CHD7, TBX1, FOXN1, PAX1 and FOXI3 genes. Most infants have 22q11.2 deletion syndrome or CHARGE syndrome (CHD7); FOXN1 and PAX1 are rarer causes.

Most cases arise from a new variant not carried by either parent, so the chance of it recurring in a sibling is low but not zero.

A confirmed variant establishes the diagnosis and is often required to enroll in gene-specific trials. The labs currently offering the test are listed in the Genetic Testing section of this page, pulled live from the NIH Genetic Testing Registry. A genetic counselor can help interpret the result and decide which relatives should be tested.

Eligibility for Congenital Athymia clinical trials depends on factors like age, diagnosis, treatment history, and overall health. Each trial sets its own inclusion and exclusion criteria. Trial Friend translates these requirements from medical language into plain English so patients can review them more easily. The Match Me tool can score your profile against active trials to help identify studies that may be a fit.

Participating in a Congenital Athymia clinical trial typically involves scheduled visits, medical tests, and close monitoring by a research team. Depending on the study phase, you may receive an investigational treatment, a placebo, or the current standard of care. Trials may last from a few weeks to several years. Study participation is voluntary, and you can withdraw at any time.