Craniofacial features associated with amelogenesis imperfecta

Craniofacial alterations occur with increased frequency in patients with amelogenesis imperfecta (AI). The purpose of this study was to characterize the craniofacial features associated with AI in families from the US. Twenty-seven people with AI and 14 unaffected family members from nine separate kindreds were evaluated. The diagnosis was established by history, clinical, and radiographic examination, and histological and or biochemical analysis of enamel. The kindreds were generally classified as hypoplastic AI (HPAI), hypocalcified AI (HCAI), or hypomaturation AI (HMAI) and then further subclassified based on phenotype and mode of inheritance. Linear and angular cephalometric measures were converted to z-scores using gender/age matched values from the Bolton and Behrent's standards. Statistical analyses included t-tests and ANOVA accepting P < or = 0.05 as significant. The vertical dimension of the lower face was significantly increased (ANSMe; P = 0.001), especially in affected individuals compared with unaffected relatives, in all kindreds with HCAI and HMAI but in only one kindred with autosomal recessive rough AI. Clinically, an anterior open bite (overbite < 0 mm) was observed in 26% of all dentate individuals with AI and none of their unaffected relatives. Skeletal morphology was highly variable depending on the AI type and kindred. While this study shows an association of altered craniofacial morphology with certain AI kindreds, the relationship of the AI genotype to the observed malocclusions remains to be defined.