Tooth agenesis refers to tooth absence during tooth development, including hypodontia, oligodontia and anodontia. Tooth agenesis, which is grouped into syndromic and non-syndromic（isolated） types according to the existence of concomitant abnormalities, could be trigered by autosomal dorminant, autosomal recessive and X-linkage inheritence under either family or isolated backgroud. Progress involving paired box gene-9, muscle segment homeobox gene-1, axis inhibitor-2, ectodermal dysplasia in associate with non-syndromic tooth agenesis is reviewed here.
