Inherited levator-medial rectus synkinesis.

We examined two sisters with lid retraction on adduction, the classic sign of levator-oculomotor synkinesis. In both women, the left eye was involved. No history of trauma or ocular surgery or complaints of diplopia were elicited, and both had good visual acuity and full ocular motility. Each exhibited 2 mm of left upper lid elevation on adduction and 4 to 6 mm of lid elevation on adduction with depression. In one of the sisters, 1 mm of ptosis was present in straight ahead gaze in the involved eye, which increased to almost 2 mm on abduction, but full levator function was observed. Four other family members in three consecutive generations were similarly affected, suggesting an autosomal-dominant mode of inheritance. To our knowledge, this type of isolated levator-oculomotor synkinesis has not been reported previously on a congenital and inherited basis.