A 4-year-old child presents with intellectual disability, characteristic 'elfin facies' (broad forehead, stellate pattern in iris, short nose with broad tip), supravalvular aortic stenosis, and a friendly personality with preserved musical abilities. Fluorescence in situ hybridization (FISH) shows a microdeletion at chromosome 7q11.23. Which gene within this region is primarily responsible for the cardiovascular and connective tissue abnormalities?

• A ELN (elastin) ✓
• B LIMK1
• C GTF2I
• D CLIP2

Explanation

Williams syndrome results from a 7q11.23 microdeletion. The ELN (elastin) gene is responsible for the characteristic cardiovascular lesions (supravalvular aortic stenosis, peripheral pulmonary stenosis) and connective tissue abnormalities. Elastin is a major component of elastic fibers in vessel walls. Loss of one copy of ELN reduces elastin production, causing stenotic arterial lesions. LIMK1 and GTF2I are within the deleted region but contribute more to neurocognitive features.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.