Phenotypes Associated with This Genotype

Genotype
MGI:2176845

• Allelic Composition: Fgf8^tm1.2Mrt/Fgf8^tm1.3Mrt; Tg(Nes-cre)1Atp/0
• Genetic Background: involves: 129P2/OlaHsd * FVB/N

• ♀: phenotype observed in females
• ♂: phenotype observed in males
• N: normal phenotype

mortality/aging

neonatal lethality, complete penetrance ( J:58999 )

• mutants die shortly after birth; lungs do not inflate so death is probably from anoxia

embryo

small first pharyngeal arch ( J:58999 )

• at E9.0 the first branchial arch is smaller than in wild-type

cellular

increased apoptosis ( J:58999 )

• at E8.75-10 extensive cell death is observed; at E9.5 the region with dying cells stretches proximally to the trigeminal swelling and included the maxillary arch-forming region

craniofacial

abnormal craniofacial morphology ( J:58999 )

• mutants have severe craniofacial defects; some mutants show a less severe phenotype with a small increase in dermal bone development and abnormalities are often observed on only one side of the head

absent molars ( J:58999 )

• molars are absent but vestigal lower incisors are present in association with the rostral process

abnormal mandible morphology ( J:58999 )

• there is little expansion of the mandible primordia as embryos mature; growth is not completely arrested as the mandibular primordial extend distally and meet at the midline

abnormal maxilla morphology ( J:58999 )

• there is little expansion of the maxilla primordia as embryos mature

absent incus ( J:58999 )

• incus and ala temporalis fail to form

abnormal craniofacial development ( J:58999 )

• there is an ectodermal covering over the prospective mouth

absent Meckel's cartilage ( J:58999 )

• body of Meckel's cartilage fails to develop

small first pharyngeal arch ( J:58999 )

• at E9.0 the first branchial arch is smaller than in wild-type

decreased tongue size ( J:58999 )

• newborns have small disorganized tongues

nervous system

abnormal trigeminal nerve morphology ( J:58999 )

• the mandibular division of the trigeminal nerve is truncated and misrouted

hearing/vestibular/ear

absent incus ( J:58999 )

• incus and ala temporalis fail to form

digestive/alimentary system

decreased tongue size ( J:58999 )

• newborns have small disorganized tongues

skeleton

absent Meckel's cartilage ( J:58999 )

• body of Meckel's cartilage fails to develop

absent molars ( J:58999 )

• molars are absent but vestigal lower incisors are present in association with the rostral process

abnormal mandible morphology ( J:58999 )

• there is little expansion of the mandible primordia as embryos mature; growth is not completely arrested as the mandibular primordial extend distally and meet at the midline

abnormal maxilla morphology ( J:58999 )

• there is little expansion of the maxilla primordia as embryos mature

absent incus ( J:58999 )

• incus and ala temporalis fail to form

growth/size/body

absent molars ( J:58999 )

• molars are absent but vestigal lower incisors are present in association with the rostral process

decreased tongue size ( J:58999 )

• newborns have small disorganized tongues