Congenital ptosis is caused by weakness of the levator palpebrae superioris muscle. It is characterized by drooping of the upper eyelid that is often present since birth. The eyelid may lag on downgaze due to tethering of the abnormal LPS muscle. Congenital ptosis can be associated with weakness of the superior rectus muscle or rare conditions like blepharophimosis syndrome. Marcus Gunn jaw-winking syndrome is a form of congenital synkinetic ptosis where stimulation of the trigeminal nerve by jaw movement causes upward jerking of the ptotic eyelid.