Purpose: The purpose of this case report is to describe a RUNX2 nonsense mutation associated with cleidocranial dysplasia (CCD) with unusual dental features. The patient was a 12-year-old Brazilian girl who sought dental care due to over-retention of primary teeth and absence of erupted permanent teeth. Clinical and radiographic examinations revealed multiple impacted permanent teeth, a prominent cingulum of the permanent impacted maxillary incisors and enamel defects (hypoplasia and hypomineralization) in addition to skeletal abnormalities. No supernumerary teeth were present. The diagnostic hypothesis of CCD was raised and the patient was refer- red to the genetic medical service, where the diagnosis was cofirmed. After RUNX2 genetic screening, including polymerase chain reaction and sequencing of both DNA strands, a heterozygous nonsense mutation was identified in exon 2 (c.193 C>T [Q65X]). This article reports unusual dental features in a patient with CCD.