DiGeorge syndrome results from failure of neural crest cell migration into the third and fourth pharyngeal pouches. Which structure is NOT derived from neural crest-populating pharyngeal arch derivatives?

• A Thymus
• B Inferior parathyroid glands
• C Conotruncal septum of the heart
• D Adrenal cortex ✓

Explanation

In DiGeorge syndrome (22q11.2 deletion), neural crest cell migration into the 3rd pharyngeal pouch derivatives (thymus, inferior parathyroids) and into the cardiac outflow tract (conotruncal septum) is defective, causing thymic hypoplasia, hypoparathyroidism, and conotruncal heart defects. The adrenal cortex derives from mesodermal cells of the intermediate mesoderm near the urogenital ridge — it is not a neural crest derivative. The adrenal medulla, however, is derived from neural crest (sympathoadrenal lineage).

Reference: BD Chaurasia's Human Anatomy, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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