Genetics The reason for tooth<unk>  has not been completely understood, despite the identification of several mutations in MSX1 and PAX9 genes which are related to tooth<unk>  and mutations in AXIN2 gene which cause oligodontia. MSX1 and PAX9 are necessary transcription factors that help to form normal teeth. Studies done in mice, have shown that MSX1 and PAX9 encode transcription factors with different DNA binding sequence patterns, a paired domain and homeodomain, which are co-expressed during tooth development. MSX1 Structure of the MSX1 protein. Based on PyMOL rendering of PDB 1ig7. MSX1 consist of homeobox encoding sequence of 60 amino acid long DNA binding homeodomain. The protein of MSX1 serves as a repressor for gene transcription and interchanges with other homeoproteins. In studies of homozygous mice, it has been found that deletion of the MSX1 gene has resulted in a double cleft palate, deficiency of the alveolar bone, failure of incisor and molar development. PAX9 PAX9 also plays a key role during embryogenesis. In addition, encoded proteins by PAX9 genes have a 128 amino acid long DNA binding paired domain. Studies suggest that all heterozygous mutations of PAX9 associated with lack of development were due to the loss of function in one of the protein copies, which resulted in haploinsufficiency. Furthermore, mutations of other genes have been identified in syndromes and congenital abnormalities in which tooth<unk>  is a regular characteristic. Endogamy There have been studies that entail that a possible reason for<unk>  was due to endogamy. A high incidence of the rare anatomical variant of MLIA was found in the population of Basta, southern Jordan. This was believed to be because of close genetic relationships. In anthropology, this would be considered a breed from closely related people or animals.
Maxillary lateral incisor agenesis
Midline cervical cleft
Maxillary hypoplasia
Hemifacial microsomia
Retrognathism
Shovel-shaped incisors
Regional odontodysplasia
Condylar hypoplasia