A 4-year-old boy's left upper eyelid drooped slightly. When he opened his mouth and pushed his jaw to the right, the eyelid briefly rose higher. And when he tried to look to the left, that eye did not move at all.
Eye specialists described the boy in the peer-reviewed journal Strabismus, calling it "an unusual association" of two congenital conditions in the same eye: Marcus Gunn jaw-winking syndrome and Duane retraction syndrome. Each comes from a nerve connecting to the wrong muscle during early development. Having both in one eye means two separate wiring errors side by side.
