Phenomenon, Marcus Gunn

Marcus Gunn phenomenon, AKA Marcus Gunn syndrome/Jaw-Winking syndrome/Marcus Gunn Ptosis/Maxillopalpebral Synkinesis, is a rare genetic disorder present at birth, characterized by movement of one upper eyelid in a rapid rising motion (open eyes) each time the jaw moves (contraction of ipsilateral lateral or medical pterygoid muscle).

• No gender preponderance
• Approximately 300 cases have been reported
• About 2%-13% of congenital ptosis
• Majority are unilateral, more often on the left

Associated Syndrome

Marin-Amat syndrome
Phenomenon, Inverse Marcus Gunn

Pearls

• Eyelid opening (CN III)
• Jaw closure (CN V3)