Craniofacial and dentoalveolar morphology in individuals with Prader–Willi syndrome: a case-control study

BACKGROUND: Prader–Willi syndrome (PWS) is a complex multisystem genetic disorder with distinct genetic and clinical features. Among other clinical symptoms, PWS is characterized by severe infantile hypotonia with feeding problems, childhood onset hyperphagia, obesity, scoliosis, short stature combined with growth hormone deficiency and developmental delay. PWS is associated with facial dysmorphology, orofacial dysfunction, oral abnormalities, low salivary flow and subsequent severe tooth wear. Little is known about the craniofacial growth direction or dental and skeletal relationships in individuals with PWS in different ages. The purpose of this study was to assess the craniofacial and dentoalveolar characteristics and to investigate the craniofacial growth direction separately in children, young adults and adults with PWS, using a cephalometric analysis of lateral cephalograms. RESULTS: Lateral cephalograms of 42 individuals with a confirmed genetic diagnosis of PWS were analysed and divided into three groups according to their age: Children (< 12 years), young adults (12–20 years) and adults (> 20 years). Cephalometric variables were compared between PWS patients and controls by age and sex. Significant deviations and distinct craniofacial patterns were found in children, young adults and adults with PWS compared with the control group. Children showed retrognatic mandible with a skeletal class II relationship, posterior growth direction and longer anterior face height. The young adults had smaller cranial base angle, a skeletal class II pattern and a higher anterior lower face than the control group. Adults with PWS had a prognathic mandible, skeletal class III relationship with anterior growth direction, more retroclined lower incisors and proclined upper incisors than the controls. Similar results were found when comparing the three groups with PWS; the adults had a prognathic mandible, skeletal class III pattern and anterior growth direction. Children had a retropositioned mandibula, skeletal class II relationship and posterior growth direction. CONCLUSION: This study may contribute to a better understanding of the craniofacial growth pattern in children, young adults and adults with PWS and may have a clinical importance when planning dental treatment, such as prosthodontics and/or orthodontics.