Mouse Genome Informatics
hm1
    Pax9tm1Hpt/Pax9tm1Hpt
involves: 129S2/SvPas * C57BL/6
Key:
phenotype observed in females WTSI Wellcome Trust Sanger Institute
phenotype observed in males EuPh Europhenome
N normal phenotype
craniofacial
• in 13% of mice all teeth are present but the lower incisors and third molars are hypoplastic
• in 35% of mice tooth defects differ between the right and left halves of the lower jaw
• at E13.5 the size of the mesenchymal cell condensations underlying the posterior part of the dental lamina is reduced, but the dental papilla of the first molar has formed
• in most cases the lower incisors are absent
• the lower first molars show significant attrition and formation of reparative and reactionary dentin
• the upper and lower third molars are unilaterally or bilaterally absent
• lower third molars and incisors may fail to erupt
• a mixture of reactionary and reparative dentin seen in molars
• in 35% of mice up to 3 teeth are absent (hypodontia) and in 52% of mice 4 or more teeth are absent (oligodontia); however the secondary palate is intact and digit duplication is not seen

endocrine/exocrine glands
N
• thymus morphology is normal and no signs of defective parathyroid or ultimobranchial body function (as shown by normal calcium and phosphate homeostasis) are seen (J:104121)

growth/size/body
• in 13% of mice all teeth are present but the lower incisors and third molars are hypoplastic
• in 35% of mice tooth defects differ between the right and left halves of the lower jaw
• at E13.5 the size of the mesenchymal cell condensations underlying the posterior part of the dental lamina is reduced, but the dental papilla of the first molar has formed
• in most cases the lower incisors are absent
• the lower first molars show significant attrition and formation of reparative and reactionary dentin
• the upper and lower third molars are unilaterally or bilaterally absent
• lower third molars and incisors may fail to erupt
• a mixture of reactionary and reparative dentin seen in molars
• in 35% of mice up to 3 teeth are absent (hypodontia) and in 52% of mice 4 or more teeth are absent (oligodontia); however the secondary palate is intact and digit duplication is not seen

Mouse Models of Human Disease
OMIM IDRef(s)
Tooth Agenesis, Selective, 3; STHAG3 604625 J:104121


Mouse Genome Informatics
ht2
    Pax9tm1Hpt/Pax9tm1Rbal
involves: 129 * C57BL/6 * CD-1
Key:
phenotype observed in females WTSI Wellcome Trust Sanger Institute
phenotype observed in males EuPh Europhenome
N normal phenotype
mortality/aging
• underrepresented at weaning

craniofacial
• at E13.5 the size of the mesenchymal cell condensations underlying the posterior part of the dental lamina is reduced, but the dental papilla of the first molar has formed
• in the upper incisors ameloblasts are present at 2 months of age but absent by 5 months
• in the upper incisors ameloblasts fail to elongate and produce only a thin layer of pre-enamel
• at P0 all third molars are arrested prior to the bud stage and the lower second molars are arrested at the bud stage
• at P0 the lower first molars have reached the bell stage but lack polarization and alignment of the ameloblasts and odontoblasts
• at P0 the upper first and second molars are mostly growth retarded
• all mice lack lower incisors
• the lower first molars show significant attrition and formation of reparative dentin
• the upper third and lower second and third molars are unilaterally or bilaterally absent
• lower third molars and incisors fail to erupt and other teeth in the lower jaw may also fail to erupt
• irregular dentin formation is indicated by the presence of 'contour lines of Owen'
• the upper incisors lack enamel; however enamel formation in the molars is normal
• more severe tooth loss than in Pax9tm1Hpt homozygotes with all mice lacking at least 4 teeth (oligodontia) and some lacking all lower teeth

growth/size/body
• at E13.5 the size of the mesenchymal cell condensations underlying the posterior part of the dental lamina is reduced, but the dental papilla of the first molar has formed
• in the upper incisors ameloblasts are present at 2 months of age but absent by 5 months
• in the upper incisors ameloblasts fail to elongate and produce only a thin layer of pre-enamel
• at P0 all third molars are arrested prior to the bud stage and the lower second molars are arrested at the bud stage
• at P0 the lower first molars have reached the bell stage but lack polarization and alignment of the ameloblasts and odontoblasts
• at P0 the upper first and second molars are mostly growth retarded
• all mice lack lower incisors
• the lower first molars show significant attrition and formation of reparative dentin
• the upper third and lower second and third molars are unilaterally or bilaterally absent
• lower third molars and incisors fail to erupt and other teeth in the lower jaw may also fail to erupt
• irregular dentin formation is indicated by the presence of 'contour lines of Owen'
• the upper incisors lack enamel; however enamel formation in the molars is normal
• more severe tooth loss than in Pax9tm1Hpt homozygotes with all mice lacking at least 4 teeth (oligodontia) and some lacking all lower teeth

endocrine/exocrine glands
N
• thymus morphology is normal and no signs of defective parathyroid or ultimobranchial body function (as shown by normal calcium and phosphate homeostasis) are seen (J:104121)

Mouse Models of Human Disease
OMIM IDRef(s)
Tooth Agenesis, Selective, 3; STHAG3 604625 J:104121