Pourfour du Petit syndrome associated with a cervical vertebral anomaly.

Pourfour du Petit syndrome is a rare dysautonomic disorder characterized by mydriasis, eyelid retraction, and hyperhidrosis and is caused by irritative stimulation of the sympathetic cervical chain. The authors describe a 45-year-old woman with iris heterochromia, who presented with episodes of ipsilateral mydriasis and hyperhidrosis and was found to have a cervical vertebral anomaly, probably present since birth, as the cause of Pourfour du Petit syndrome.