This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunity disorders, Subject name: Pathology
A neonate develops spastic contractions on the second postpaum day. Laboratory studies show hypocalcemia. MRI studies demonstrate aplasia of the thymus and parathyroid glands. What is the appropriate diagnosis? 
Select and explain. 
A. Adenosine deaminase deficiency, B. Common variable immunodeficiency, C. DiGeorge syndrome, D. Transient hypogammaglobulinemia of infancy
C: DiGeorge syndrome
Answer: C: DiGeorge syndrome 
Explanation: DiGeorge syndrome Chromosomal defect (22q11 deletion) that results in developmental anomalies of the branchial (pharyngeal) pouches and organs that develop from these embryonic structures (thymus, parathyroids, and aoic 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. Diagnosis: DiGeorge syndrome