Successful treatment of hereditary trembling chin with botulinum toxin.

Hereditary trembling chin is an autosomal dominant condition characterized by recurrent bouts of tremor involving the chin. These episodes are precipitated by emotional upset. There has been considerable debate about the gravity of this condition. This may be a benign movement disorder; however, the rhythmic trembling of mentalis at rest or during times of stress in these patients is often misinterpreted as betraying an incipient emotional upset. For this reason, some patients with this condition may find it socially disabling. We have recently successfully treated one such family with regular botulinum toxin injections to the mentalis muscle.