A 5-month-old male infant is brought to your clinic for a follow-up appointment. Mother reports that the boy has had several viral and fungal infections since his birth and she has noticed that he often is stiff and rigid. On examination you notice the boy has a small jaw, cleft palate, hypertelorism, slanting palpebral fissures, and short philtrum. When you tap on his facial nerve, you notice twitching of the facial muscles. Laboratory testing demonstrates hypocalcemia, decreased levels of parathyroid hormone, and absence of serum T cells. Chest x ray is significant for the absence of thymic shadow. Fluorescence in situ hybridization (FISH) study reveals a microdeletion of chromosome 22 at the 22q11.2 locus. Of the following, which is most likely observed in babies with this disorder?
