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

Mutations in human and in mouse orthologous genes <i>Amelx</i> and <i>Enam </i>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 <i>Amelx</i><sup>WT</sup>, <i>Amelx</i><sup>X/Y64H</sup>, <i>Amelx</i><sup>Y/Y64H</sup>, <i>Amelx</i><sup>Y64H/Y64H</sup>, and<i> Enam</i><sup>WT</sup>, <i>Enam</i><sup>Rgsc395</sup> heterozygous and <i>Enam</i><sup>Rgsc395</sup> 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 <i>Amelx</i> groups for mandible and incisor size and enamel colour and between the <i>Enam</i> groups for incisor size and enamel colour. The <i>Amelx</i><sup>WT</sup> mice had the largest mandibles and incisors, followed in descending order of size by the <i>Amelx</i><sup>X/Y64H</sup>, <i>Amelx</i><sup>Y/Y64H</sup> and <i>Amelx</i><sup>Y64H/Y64H</sup> mice. Within the <i>Enam</i> groups the <i>Enam</i><sup>WT</sup> incisors were largest and the <i>Enam</i><sup>Rgsc395</sup> 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.