4q13.3

Odontogenic tumors

Odontogenic tumours arise from the residues of odontogenic epithelium and/or ectomesenchyme, as a result of disturbances in the development of teeth and associated structures.

AMBN gene is mutated in ameloblastomas and others odontogenic tumors (Toyosawa et al., 2000; Perdigão et al., 2004; Perdigão et al., 2009). Ambn-null mice develop odontogenic tumors of dental epithelium origin (Fukumoto et al., 2004). AMBN expression prevents odontogenic tumor development by suppressing cell proliferation and maintaining differentiation phenotype through Msx2, p21, and p27 (Sonoda et al., 2009). The absence of ameloblastin in epithelial odontogenic tumors has been considered a useful marker for the functional differentiation of secretory ameloblast (Takata et al., 2000).

Amelogenesis imperfecta

Amelogenesis imperfect is a common group of inherited defects such as hypoplastic or hypomineralized enamel. Autosomal dominant, autosomal recessive, and X-linked forms of amelogenesis imperfect are recognized.

Amelogenin and ameloblastin have an impaired secretion in ameloblasts of phenocopies human X-linked amelogenesis imperfect mice, which results in severe enamel bio-mineralization defects, loss of ameloblast phenotype, increased ameloblast apoptosis, and formation of multi-cellular masses (Barron et al., 2010). AMBN mutations in the coding region or splice sites were discarted to be responsible for autosomal dominant amelogenesis imperfecta (Mardh et al., 2001).