FAQ

Congenital athymia is an ultra-rare, life-threatening immune disorder in which a baby is born without a functioning thymus. Without a thymus, the body cannot develop mature T cells, leaving children unable to fight infections or regulate their immune system.

The thymus is a small organ located behind the breastbone. Although it is only active during childhood, it plays a critical role in teaching T cells how to recognize infections while preventing them from attacking the body’s own tissues.

Congenital athymia affects approximately 1 in 4 million babies, with fewer than 15 babies diagnosed each year in the United States. Fewer than 300 people worldwide are currently living with the condition.

Congenital athymia can occur as part of several genetic conditions, including:

• CHARGE syndrome
• FOXN1 deficiency
• TBX1 abnormalities
• Complete DiGeorge syndrome (22q11.2 deletion syndrome)
• Untreated gestational diabetes

In some children, the exact cause is never identified.

Symptoms often appear within the first weeks or months of life and may include:

• Recurrent or severe infections
• Persistent viral or fungal infections
• Poor growth
• Chronic diarrhea
• Skin rashes
• Failure to thrive
• Absent or extremely low T cells on newborn screening

Many babies are first identified through newborn screening, which detects very low or absent T cells. The diagnosis is confirmed through specialized blood testing, immune system evaluations, genetic testing, and imaging when appropriate.

No. Although both conditions cause severe T-cell deficiency, they are different diseases.

• Congenital athymia: The body cannot produce T cells because there is no functioning thymus.
• SCID: T cells are unable to develop properly due to genetic defects within the immune cells themselves.

The treatments are also different.

Yes. The only treatment that addresses the underlying cause is a cultured thymus tissue transplant (Rethymic®), which allows the body to begin producing functional T cells over time.

Children often require supportive care before and after transplant, including:

• Immunoglobulin (Ig) replacement therapy
• Preventive antibiotics, antivirals, and antifungals
• Protective isolation
• Frequent monitoring by immunologists

Yes. The only treatment that addresses the underlying cause is a cultured thymus tissue transplant (Rethymic®), which allows the body to begin producing functional T cells over time.

Children often require supportive care before and after transplant, including:

• Immunoglobulin (Ig) replacement therapy
• Preventive antibiotics, antivirals, and antifungals
• Protective isolation
• Frequent monitoring by immunologists

Immune reconstitution is gradual. Most children begin developing new T cells over many months, with continued improvement over 1–2 years or longer. Every child’s recovery is unique.

Many children go on to attend school, make friends, play sports, travel, and enjoy childhood. Some continue to need medical follow-up or treatments, but a thymus transplant can provide the opportunity for a dramatically healthier future.

No. Congenital athymia is a genetic or developmental condition and cannot be spread from person to person.

Without treatment, congenital athymia is life-threatening. Early diagnosis allows families to begin infection prevention, receive specialized care, and be evaluated for a thymus transplant before severe complications occur.

 You can make a meaningful difference by:

• Learning about congenital athymia and sharing accurate information.
• Donating plasma to help create lifesaving immunoglobulin therapies.
• Supporting organizations dedicated to advocacy, education, and family assistance.
• Donating to the Luca Rising Foundation to help provide resources, awareness, and hope for families navigating congenital athymia.

• Immune Deficiency Foundation (IDF) – Information about primary immunodeficiencies
• Luca Rising Foundation - Education, advocacy, and family support
• Enzyvant Therapeutics – Information about congenital athymia and Rethymic®