The heterogeneity of craniofacial morphology in Prader-Willi patients.

Prader-Willi syndrome is a complex genetic disorder with narrow spectrum of facial phenotypic signs, which make the clinical diagnosis difficult in some cases. There are several reports describing the craniofacial appearance of Prader-Willi patients, but there are only a few cephalometric studies for these patients. In this study were included 18 patients with Prader-Willi syndrome and a control group of 18 subjects of both sexes selected based on specific criteria. The cephalometric radiographs of the patients were taken using the standardized technique with centric teeth in occlusion and lips in relaxed position. Angular, horizontal and linear measurements were analyzed for the study group and for the control group. We established that in Prader-Willi patients, there is a decrease of the majority of parameters but the degree of this reduction varies widely between patients and clinically typical facies not always have smaller measurements which can be found in an unusual facies. Facial dysmorphism in Prader-Willi patients varies a group ranging from miss proportions that do not alter the facial architecture as regard of facial typology, skeletal class and pattern of development to a severe disturbance of those. There is a degree of clinical heterogeneity between subjects with Prader-Willi syndrome on clinical evaluation and cephalometric study confirms the heterogeneity for this patients. Because the identification of smaller dimensions for majority of parameters in children and adults, the possibility of developmental delay or growth retardation delay can be excluded. These findings are important for the orthodontist for optimum timing of orthodontic management of patients with Prader-Willi syndrome.