A neonate develops spastic contractions on the second post-partum day Laboratory studies show hypocalcemia. MRI studies demonstrate aplasia of the thymus and parathyroid glands. What is the appropriate diagnosis?

DiGeorge syndrome. DiGeorge syndrome is a chromosomal defect that results in developmental anomalies of the branchial (pharyngeal) pouches and organs that develop from these embryonic structures (thymus, parathyroids, and aortic arch). These children present with tetany caused by hypoparathyroidism and deficiency of cellular immunity. They also have characteristic facial features ("angry look"). In the absence of a thymus, T-cell maturation is interrupted at the pre-T stage. DiGeorge syndrome has been corrected by transplanting thymic tissue. None of the other choices are associated with thymic aplasia.Diagnosis: DiGeorge syndrome