Understanding Congenital Athymia

Congenital athymia is an ultra-rare condition in which a baby is born without a functioning thymus. Without the thymus, the body cannot develop healthy T cells needed to fight infections, resulting in profound immune deficiency.

The thymus is a small organ in the upper chest that acts as a school house to educate and develop infection-fighting T cells, especially during infancy and childhood. These naive T-cells are the cornerstone for infection fighting.

Congenital athymia is most often caused by genetic changes that disrupt the thymus’s development before birth. Common associated causes include: 22q11.2 deletion syndrome, CHARGE syndrome, FOXN1 and PAX1, and untreated gestational diabetes. 

Congenital athymia is often first suspected after newborn screening shows very low T-cell receptor excision circles (TRECs). Doctors. Blood tests, including flow cytometry, to measure T cells and confirm that naïve T cells are extremely low or absent. Genetic testing can then aid in the diagnosis. 

Congenital athymia occurs when the thymus is absent or nonfunctioning. SCID is caused by genetic defects within the immune system that prevent T cells, and sometimes B and NK cells from functioning. Both cause severe immune deficiency, but their underlying causes and treatments differ.

https://primaryimmune.org/understanding-primary-immunodeficiency/types-of-pi/congenital-athymia

https://rarediseases.org/rare-diseases/congenital-athymia/?utm_source=chatgpt.com