Phenotypic diversity and revision of the nomenclature for autosomal recessive amelogenesis imperfecta

Purpose. The purpose of this study was to characterize the phenotype in 9 families with autosomal recessive amelogenesis imperfecta (ARAI), and to propose a classification system allowing inclusion and delineation of diverse ARAI phenotypes. Study design. Nine families with ARAI were evaluated clinically and radiographically. Exfoliated and extracted teeth were examined via light and scanning electron microscopy, with the enamel in one case evaluated by amino acid analysis. Results. The 9 families demonstrated diverse ARAI phenotypes including localized hypoplastic, generalized thin hypoplastic, hypocalcified and hypomaturation AI types. Conclusions. Some ARAI phenotypes observed in this study and reported in the literature cannot be classified using currently accepted ARAI nomenclature. Therefore, we propose a revised nomenclature permitting both classification of all ARAI clinical forms and inclusion of anticipated molecular-based nomenclature, such as now exists for some X-linked and autosomal dominant AI subtypes.