Oculopalpebral synkinesis in congenital ptosis: a case series expanding the spectrum of congenital cranial dysinnervation disorders

Purpose: Oculopalpebral synkinesis is an involuntary change in eyelid position linked to eye movement, distinct from the jaw-triggered eyelid movement of the Marcus Gunn jaw-winking phenomenon (MGJWP). It is increasingly considered part of the spectrum of congenital cranial dysinnervation disorders (CCDDs), yet only isolated case reports have described it.Methods: We examined three patients with congenital ptosis whose eyelid position varied with gaze. Eye movements were documented with clinical photographs.Results: Case 1, an 8-year-old boy, had right congenital ptosis with a classic MGJWP and a monocular elevation deficit. The right ptosis worsened on levoversion, and the left upper eyelid, which had no baseline ptosis, moved intermittently up and down on adduction: a double synkinesis. Case 2, a 25-year-old woman, had severe bilateral ptosis and jerk nystagmus since birth, without MGJWP; ptosis worsened in the adducting eye and improved in the abducting eye. Case 3, a 9-year-old girl, had severe right ptosis, right exotropia of 10°, bilateral torsional nystagmus and mild bilateral limitation of elevation, with alternating blepharoptosis in a reciprocal pattern between the two eyelids. MRI of the brain was normal where reported.Conclusion: The same eyelid phenomenon can arise from different aberrant connections between the horizontal rectus muscles and the levator palpebrae superioris, with or without a trigeminal component. We propose that these cases form a distinct group of CCDDs in which synkinesis occurs without significant limitation of ocular motility. Functional MRI and genetic studies are needed to clarify the cause.