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
Phenomenon, Inverse Marcus Gunn
- Eyelid opening (CN III)
- Jaw closure (CN V3)