A 2-year-old child has a unilateral facial capillary malformation, limb hypertrophy, and recurrent bleeding from vascular lesions. Which gene mutation is most likely responsible?

• A RASA1
• B VEGFR3
• C TSC2
• D PIK3CA ✓

Explanation

This describes a PIK3CA-related overgrowth spectrum disorder such as Klippel-Trenaunay syndrome or CLOVES syndrome. Somatic activating mutations in PIK3CA cause capillary malformations with limb hypertrophy. RASA1 mutations cause capillary malformation-arteriovenous malformation. VEGFR3 mutations cause Milroy disease (primary lymphedema). TSC2 mutations cause tuberous sclerosis complex.

Reference: Nelson Textbook of Pediatrics, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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