Solitary median maxillary central incisor syndrome (SMMCIS) is a rare anomaly that affects 1 in 50,000 live births. Of unknown etiology, SMMCIS is characterized by the presence of a single central incisor located on the maxillary midline and may be associated with developmental defects and systemic alterations. SMMCIS also is associated with short stature, mild forms of deviation in craniofacial morphology, and intellectual disability. The purposes of this paper were to: describe the clinical case of an 8-year-old boy with a permanent central incisor located at the midline in association with holoprosencephaly; and highlight the most important aspects related to diagnosis and treatment of solitary median maxillary central incisor syndrome.