First case of bilateral coronoid hyperplasia in monozygotic twin sisters-a new aetiological perspective?

BACKGROUND: Mandibular coronoid hyperplasia is a rare condition associated with gradual reduction in mouth opening. Its aetiology is unknown but increased temporalis activity, endocrine stimulus, trauma and familial causes have been proposed. CASE REPORT: In this article, we present a case of bilateral coronoid hyperplasia presenting with limited mouth opening in 16-year-old Caucasian twin sisters. DISCUSSION: This report gives a new perspective to the aetiology of coronoid hyperplasia since it describes its occurrence in monozygotic twins and hence provides a strong argument in support of a genetic aetiology.