Supplementary Material for: Phenotype-Genotype Correlations in Mouse Models of Amelogenesis Imperfecta Caused by Amelx and Enam Mutations

Mutations in human and in mouse orthologous genes Amelx and Enam result in a diverse range of enamel defects. In this study we aimed to investigate the phenotype-genotype correlation between the mutants and the wild-type controls in mouse models of amelogenesis imperfecta using novel measurement approaches. Ten hemi-mandibles and incisors were dissected from each group of AmelxWT, AmelxX/Y64H, AmelxY/Y64H, AmelxY64H/Y64H, and EnamWT, EnamRgsc395 heterozygous and EnamRgsc395 homozygous mice. Their macro-morphology, colour and micro-topography were assessed using bespoke 2D and 3D image analysis systems and customized colour and whiteness algorithms. The novel methods identified significant differences (p ≤ 0.05) between the Amelx groups for mandible and incisor size and enamel colour and between the Enam groups for incisor size and enamel colour. The AmelxWT mice had the largest mandibles and incisors, followed in descending order of size by the AmelxX/Y64H, AmelxY/Y64H and AmelxY64H/Y64H mice. Within the Enam groups the EnamWT incisors were largest and the EnamRgsc395 heterozygous mice were smallest. The effect on tooth morphology was also reflected by the severity of the enamel defects in the colour and whiteness assessment. Amelogenin affected mandible morphology and incisor enamel formation, while enamelin only affected incisors, supporting the multifunctional role of amelogenin. The enamelin mutation was associated with earlier forming enamel defects. The study supported the critical involvement of amelogenin and enamelin in enamel mineralization.