Which immune disease is associated with congenital thymic hypoplasia and can be diagnosed through T-cell subset enumeration by flow cytometry?

The correct answer, DiGeorge syndrome, is a genetic condition that results from a deletion of a small segment of chromosome 22 and is characterized by congenital thymic hypoplasia. This leads to an underdeveloped thymus, which is essential for T-cell development and maturation. As a consequence, individuals with DiGeorge syndrome often have a deficiency in T-cells, resulting in increased susceptibility to infections.

To diagnose this condition, T-cell subset enumeration by flow cytometry is utilized. This technique allows for the measurement of different T-cell populations in the blood, which can reveal a significant deficiency in T-lymphocytes, confirming the diagnosis of DiGeorge syndrome.

In contrast, Severe Combined Immunodeficiency (SCID) also presents with T-cell deficiencies, but it is primarily characterized by the absence of both T- and B-cells, rather than just T-cell hypoplasia. Wiskott-Aldrich syndrome involves a triad of symptoms (eczema, thrombocytopenia, and immunodeficiency) but is not specifically linked to thymic hypoplasia. HIV/AIDS affects T-cells but is an acquired immunodeficiency rather than a congenital condition. Thus, the specific association of congenital thymic hypoplasia with