Description: Enamel formation is a strictly regulated process in which various genes and their products are involved. Mutations in any of them can result in defective development. Amelogenesis imperfecta (AI) is an inherited tooth disease affecting the structure, composition, and amount of enamel formed in the process of amelogenesis. Non-syndromic and syndromic forms are known, and several genes responsible for various aspects of enamel physiology have been described. Non-syndromic AI also occurs spontaneously in dogs with known autosomal recessive variants in the ACP4 (Hytönen et al., 2019), ENAM (Gandolfi et al., 2013; Hytönen et al., 2019), and SLC24A4 (Pedersen et al., 2017) genes. Affected dogs have a rough tooth surface with brown spots in places where the enamel is thin or completely absent. Their teeth can be smaller, and pointed, with large gaps between the individual teeth. They are more prone to dental plaque, fractures, gingivitis, pulpitis, or other periodontal diseases.
The SLC24 gene family (solute carrier 24) includes potassium-dependent Na + / Ca 2+ pumps serving as bidirectional membrane transporters. The SLC24A4 gene on chromosome 8 encodes a protein involved in Na + / Ca 2+, K + transport during amelogenesis. SLC24A4 is primarily expressed in ameloblasts during the maturation phase, suggesting that its function is critical for strengthening and promoting enamel mineralization during maturation (Hu et al., 2012). Thus, during tooth development, it ensures the transfer of calcium to the newly formed enamel. The need for calcium transport proteins during amelogenesis was confirmed by the identification of mutations in the SLC24A4 gene that cause enamel malformations. Pedersen et al. published 2017 a new variant of hypomaturated type AI in the Samoyed breed. This is a 21 bp insertion in exon 17 in the terminal transmembrane region of the SLC24A4 gene. Insertion of this size alters the inner membrane portion of the protein and probably inhibits its Na + / Ca 2+, K + pump function. The incidence of AI carriers in the tested Samoyeds is lower than e.g. in the Italian Greyhound, but the disease in Samoyeds is more severe.
Inheritance: autosomal recessive
Mutation: 21 bp insertion in SLC24A4 gene
Sample: EDTA whole blood (1.0 ml) or 2 buccal brushes
The analysis is suitable for the following breeds: Samoyed