Phenotypes associated with this allele

• Allele Symbol: Crabp2^tm1Ipc
• Allele Name: targeted mutation 1, Pierre Chambon
• Allele ID: MGI:2183745
• Summary: 2 genotypes

Jump to	Allelic Composition	Genetic Background	Genotype ID
hm1	Crabp2^tm1Ipc/Crabp2^tm1Ipc	either: (involves: 129S2/SvPas) or (involves: 129S2/SvPas * C57BL/6)	MGI:3700281
cx2	Crabp1^tm1Ipc/Crabp1^tm1Ipc Crabp2^tm1Ipc/Crabp2^tm1Ipc	involves: 129S2/SvPas * C57BL/6	MGI:3700280

Genotype
MGI:3700281

hm1

• Allelic Composition: Crabp2^tm1Ipc/Crabp2^tm1Ipc
• Genetic Background: either: (involves: 129S2/SvPas) or (involves: 129S2/SvPas * C57BL/6)

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

limbs/digits/tail

polydactyly ( J:23139 )

• at P0-P42, ~45% of homozygotes show a limb outgrowth on the post-axial side of digit 5, either unilaterally or bilaterally, and most often on the forelimbs only

• this digit outgrowth is of variable size and is rarely observed on all four limbs (0.3%)

• the most conspicuous digit outgrowths contain a cartilaginous and/or bony element

• however, homozygotes are grossly normal in terms of growth, fertility and viability, with no major skeletal defects other than the limb malformation noted in some fetuses at E18.5

• retinoic acid (RA) excess treatment in utero fails to increase the frequency of digit outgrowth, indicating normal sensitivity of mutant embryos to RA excess

Genotype
MGI:3700280

cx2

• Allelic Composition: Crabp1^tm1Ipc/Crabp1^tm1Ipc; Crabp2^tm1Ipc/Crabp2^tm1Ipc
• Genetic Background: involves: 129S2/SvPas * C57BL/6

mortality/aging

premature death ( J:23139 )

• ~9% of double homozygotes die before 6 weeks of age

limbs/digits/tail

polydactyly ( J:23139 )

• at P0-P42, 83% of double homozygotes show a forelimb outgrowth on the post-axial side of digit 5, either unilaterally (27%) or bilaterally (52%)

• this pots-axial digit outgrowth is of variable size and is also observed on all four limbs at a low frequency (4%)

• in severe cases, the digit rudiment bones are always floating

• in addition, 13% of double homozygotes display a pre-axial digit outgrowth in their hindlimbs, consisting of two bones not fully separated by a joint

• retinoic acid (RA) excess treatment in utero fails to increase the frequency of digit outgrowth, indicating normal sensitivity of double mutant embryos to RA excess

hearing/vestibular/ear

hearing/vestibular/ear phenotype ( J:89666 )

N • contrary to expectation, E18.5 double homozygotes show normal cochlear morphology with no structural changes at the level of the organ of Corti relative to wild-type mice

N • in addition, double homozygotes show no significant differences in ABR thresholds and latencies or DPOAEs relative to wild-type mice, indicating normal auditory function