A three-dimensional comparison of the modifying effects of familial genetic contribution in Turner syndrome.

Comparison of individuals affected by chromosomal aneuploidies with controls has already confirmed the differential action of X and Y chromosomes during dental ontogeny. Permanent enamel and dentin structures are formed during the development of the dentition and these reflect the combined effects of both genetic and environmental factors during the prenatal and early postnatal period. It can provide key information on the effect of developmental assaults such as chromosomal aneuploidy as it is not subject to subsequent resorption or remodelling like other skeletal structures within the body. Dental features seen in Turner syndrome (TS) include significantly smaller teeth than controls and a narrow, deeply vaulted palate. Familial genetic contribution is known to have a modifying effect on features such as palate width. During the last two decades imaging and analysis techniques have undergone rapid evolution. Each development offers new possibilities for describing and defining structures within the body. This pilot study used a novel 3D system to measure the dentition of 10 individuals with TS and 10 unrelated female controls. The reliability of the method and its effectiveness in quantitatively describing differences between the two groups was verified. A larger study involving TS individuals, their first degree unaffected female relatives and female controls (n=35 each group) is underway which will use the new 3D system to describe the surface morphology, volume and contours of the dentition in order to quantify the effect of TS on dental development and to assess any modifying effects of familial genetic contribution.