Solitary Median Maxillary Central Incisor syndrome is a rare condition (prevalence 1:50,000), with the characteristic dental feature of a solitary central incisor in the maxilla, positioned exactly in the midline. This single incisor is symmetrical and can be present in the deciduous as well as in the permanent dentition. The syndrome can occur as a mild form of the broad holoprosencephaly-spectrum, but can also be associated with other characteristics. The etiology is still largely unknown, but the syndrome is probably based especially on genetic causes. Early recognition of the syndrome is of great importance for establishing the diagnosis, for additional investigation, for possible treatment of associated anomalies and for the correct advice concerning the risk of inheritance of severe congenital birth defects, related to holoprosencephaly. Dentists and orthodontists can play an important role in this regard and should therefore be able to recognise the clinical features of this condition and know how to refer a patient for further diagnostic counselling.