There is no thymus = DiGeorge

Think back to Step 1 embryology (thymus forms from third and fourth pharyngeal pouches)

• Infant presenting with grunting and breathing difficulty found to be hypocalcemic with absent thymic shadow and infection with an organism commonly seen in patients with HIV and other forms of cellular (T cell) deficiency, most consistent with DiGeorge syndrome
• Mnemonic for symptoms for CATCH-22: Cardiac abnormalities (often Tetralogy of Fallot), Abnormal facies, Thymic aplasia, Cleft palate/lip, Hypocalcemia (secondary to parathyroid a/dysgenesis)