Phenotypes Associated with This Genotype

Genotype
MGI:2673171

• Allelic Composition: Hoxb4^tm1Bay/Hoxb4^tm1Bay
• Genetic Background: involves: 129S7/SvEvBrd * C57BL/6J

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

mortality/aging

decreased survivor rate ( J:4612 )

• only 50% of homozygotes survive to adulthood

prenatal lethality, incomplete penetrance ( J:4612 )

• Background Sensitivity: on a mixed genetic background involving 129S7/SvEvBrd and C57BL/6J, only 50% of the expected number of homozygotes are recovered at weaning with no deaths noted after P1-P2, suggesting that 50% of homozygotes die shortly after birth or during development; in contrast, on a co-isogenic background, 100% of homozygotes die within 1 day of birth

growth/size/body

abnormal chest morphology ( J:4612 )

• some homozygotes exhibit a concave chest

decreased body size ( J:4612 )

• surviving adult homozygotes are smaller than normal in size but remain healthy

skeleton

abnormal sternebra morphology ( J:4612 )

• homozygotes show variable defects in the fusion of paired sternal rudiments, resulting in partial or completely duplicated sternebrae

• phenotype ranges from a normal or a mildly affected sternum in surviving adult homozygotes to a completely split sternum in homozygotes that die early

split sternum ( J:4612 )

• a completely split sternum is observed in homozygotes that die early

abnormal cervical axis morphology ( J:4612 )

• some homozygotes display a partial anterior homeotic transformation of the second cervical vertebra or axis (C2) to atlas (C1)

• an ectopic ventral tubercle is observed on C2, along with a broadened neural arch

• in contrast, the dens and vertebral body appear unaffected

cervical vertebral transformation ( J:4612 )

• some homozygotes display a partial anterior homeotic transformation of the second cervical vertebra or axis (C2) to atlas (C1)

• a C3 to C2 transformation is rarely observed at the neural arch level

muscle

diaphragmatic hernia ( J:4612 )

• some homozygotes display hernias in the retrosternal part of the diaphragm involving the liver (most cases) or intestine (3 of 25)