Background. The authors present an unusual complication of mandibular distraction in a child with the curious condition of multiple pterygium syndrome is presented. Case report. The patient was a Caucasian male with severe pterygia in his neck. As a result of his limited mouth opening and restricted upper airway leading to obstruction, he underwent lengthening of his mandible by distraction, which significantly improved his breathing. During his follow-up, it was observed that an unusually elongated permanent molar was present in an abnormal position. Conclusion. This case highlights the need to carefully plan the sites for osteotomy and the potential for damage to the developing permanent dentition in young children.