Genetic study of maxillary midline diastema

Maxillary midline diastema (MMD) is a common esthetic problem. It is an easily identifiable condition and one that is often recognized by laypeople. Furthermore, social and psychological well-being can be influenced by an individual's perception of his or her facial characteristics. There are a number of treatment modalities available to treat MMD. A wide range of prevalence values for MMDs has been reported ranging from 1.6% to 25.4% in adult populations.

OBJECTIVE: The goal of our study was to evaluate occurrence of MMD in close relatives of individuals affected with this condition.

MATERIAL AND METHODS: Our sample consisted of 424 DDS students at the dental school. There were 251 males and 173 females. Each student completed a questionnaire focused on occurrence of MMD in his/her family, drew a pedigree and answered questions regarding of his/her MMD status (yes or no). If the answer was positive, further details regarding size and treatment of MMD were obtained. All information was entered into FoxPro database and analyzed using EPISTAT and CONFIG software.

RESULTS: All students who reported having or being treated for MMD ≥ 0.1 mm were included as probands in our study. Out of 424 individuals, 70 reported having or being treated for MMD giving prevalence of 16.51 per 100 (95% CI = 13.17-20.47). The vast majority of probands (42%) reported MMD from 0.76 to 1.00 mm. Significantly higher prevalence of MMD (34.71/100; 95% CI = 29.06-40.82) was found in 1st degree relatives (p<0.0001). Risk of recurrence for siblings of a proband with MMD was found as 40.8%.

CONCLUSIONS: Our study suggests that MMD has a strong genetic component when including MMD ≥ 0.1 mm. The risk of recurrence for siblings is suggesting that an autosomal dominant type of inheritance may be responsible for some cases.