The exact cause of Moebius syndrome is not known. Researchers suspect that, like many other rare conditions, it is most likely caused by many different factors. More research is needed.
Rarely, Moebius syndrome has occurred in families (less than 2% of cases), suggesting there may be a genetic component in some cases. Most Moebius syndrome cases develop randomly (sporadically) in people with no family history of the disorder.
Moebius syndrome is extremely rare. While the exact number of cases worldwide is unknown, it is estimated to occur in every two to 20 people per million. Males and females are equally affected.