Which syndrome features congenital heart disease, immunodeficiency, and hypoparathyroidism associated with a chromosome 22 deletion?

• A. DiGeorge syndrome
• B. Cri du chat syndrome
• C. Marfan syndrome
• D. Angelman syndrome

Answer: (A)

This combination points to a deletion on chromosome 22q11.2 that disrupts the development of the pharyngeal apparatus, particularly the third and fourth pharyngeal pouches which give rise to the thymus and parathyroid glands. When these structures are underdeveloped, you get immunodeficiency from thymic aplasia and hypoparathyroidism from absent or undersized parathyroids, along with common conotruncal heart defects such as truncus arteriosus or tetralogy of Fallot. This constellation is the hallmark of DiGeorge syndrome, also known as 22q11 deletion syndrome or velocardiofacial syndrome. The other options are associated with different genetic changes and clinical pictures—for example, Cri du chat involves a deletion on chromosome 5 with a characteristic crying cat-like cry, Marfan syndrome is due to FBN1 mutations affecting connective tissue, and Angelman syndrome results from a maternal UBE3A gene issue on chromosome 15.