Clinical and genetics features in patients with syndromic hypodontia and hyperdontia

Background: The tooth is a specialized organ of the max- illofacial skeleton, and its development involves a series of lengthy and complex stages. Tooth development is influ- enced by genetic and environmental factors. Tooth num- ber, position, structure, and shape are under the control of a complex system of certain genes whose modifications may result in dental anomalies. Depending on the stage of tooth development where alteration takes place, different dental anomalies could occur in terms of number (ano- dontia, hypodontia, and hyperdontia), structure (amelo- genesis imperfecta [AI], dentinogenesis imperfecta, and dentin dysplasia), and shape (microdontia, macrodontia, and taurodontism). These anomalies may be associated with systemic disorder (syndromic) or isolated (non- syndromic). Dental anomalies may create problems of aesthetics as well as speech, which requires a multidis- ciplinary approach for the treatment of these anomalies. The aim of this study was to assess the clinical genetic findings of a cohort of patients, 3 affected by cleidocranial dysplasia and 7 by hypohidrotic ectodermal dysplasia. Methods: Clinical and genetic analysis have been carried out in a multiethnic cohort of 7 patients affected by hypo- hidrotic ectodermal dysplasia (HED) and 3 by cleidocra- nial dysplasia (CCD). Results: Mutational spectrum of identified mutations in EDA, EDAR, EDARADD, and RUNX2 genes along with the phenotypic eterogeneity of the cohort is reported and widely discussed. Anomalies in tooth shape and number was identified in all participants to this study. No statisti- cal analysis was required. Conclusions: We report on a clinical genetic case series of syndromic hypodontia and hyperdontia in genetic enti- ties known as HED and CCD, from diagnosis to treatment, concluding that in such diseases you may expect a variety of dental anomalies between shape and number.