A neonate is note to have an abnormally shaped face with a very small jaw. On examination he has systolic murmur. Several hours after bih, the baby develops convulsions and tetany. Serum chemistries show Sodium 40mEq/L Potassium 4mEq/L Chloride 100mEq/L Bicarbonate 24mEq/ L Magnesium 2mEq/L Calcium 5mEq/dL Glucose 100mg/ dL This child's disorder is associated with aplasia or hypoplasia of which of the following organs?

Dysmophic features with low calcium and murmur point towards DiGeorge syndrome. Features can be summarized using the mnemonic CATCH-22 to describe DiGeorge syndrome, with the 22 to remind one the chromosomal abnormality is found on the 22 chromosome, as below Cardiac Abnormality (especially tetralogy of fallot) Abnormal facies Thymic aplasia Cleft palate Hypocalcemia/Hypoparathyroidism. Reference: GHAI Essential pediatrics, 8th edition