Oral-facial-digital syndrome type I (OFDI) is a congenital X-linked dominant disorder characterized by anomalies of the oral cavity, face and digits sometimes associated to cerebral malformations and polycystic kidney disease. The gene, responsible for this syndrome, is ofd1. Clinically it is seen only in females. Lesions of the mouth include median pseudoclefting of the upper lip, clefts of the palate and tongue, and dental anomalies (missing or supernumerary teeth, enamel hypoplasia, and teeth malpositions). Dysmorphic features affecting the head include hypertelorism, frontal bossing, micrognathia, facial asymmetry and broadened nasal ridge. The digital abnormalities are syndactyly, clinodactyly, brachydactyly and, rarely, pre or post-axial polydactyly. Less frequently ex-pressed phenotypic anomalies include skin milia, alopecia, deafness and trembling. Sometimes the diagnosis of OFDI can be difficult because there is an overlap with other types of oral-facial-digital syndromes. A sporadic case of OFDI, with 7 lower incisors, both in the primary and permanent dentition, is reported. This dental anomaly is very unusual because in literature only supernumerary cuspids are reported. In the light of this case, the authors discuss the oral phenotypic expression of ofd1 gene and its role in human odontogenesis.