Phenotypes associated with this allele

• Allele Symbol: kkt
• Allele Name: kyphoscoliosis kinked tail
• Allele ID: MGI:2670329
• Summary: 3 genotypes

Jump to	Allelic Composition	Genetic Background	Genotype ID
hm1	kkt/kkt	involves: C57BL/6 * CBA	MGI:2675315
ht2	kkt/kkt^+	involves: C57BL/6 * CBA	MGI:4437565
cx3	kkt/kkt^+ Pax1^un/Pax1^+	involves: C57BL/6 * CBA	MGI:4437579

Genotype
MGI:2675315

hm1

• Allelic Composition: kkt/kkt
• Genetic Background: involves: C57BL/6 * CBA

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

limbs/digits/tail

kinked tail ( J:60410 )

• all homozygotes display a kinked tail characterized by severe undulation

skeleton

abnormal scapula morphology ( J:60410 )

absent acromion ( J:60410 )

• the acromion process of the scapula is absent

abnormal axial skeleton morphology ( J:60410 )

abnormal neurocranium morphology ( J:60410 )

• newborn homozygotes display a flatter neurocranium with a snub-nosed appearance

• however, the craniofacial skeleton is overtly normal

sternebra fusion ( J:60410 )

• newborn homozygotes display fusion of the fourth and fifth sternebrae

• multiple sternebrae are occasionally fused together due to ossification of the corresponding intersternebrae

abnormal vertebral column morphology ( J:60410 )

• newborn homozygotes display skeletal anomalies along the vertebral column

• the most severe abnormalities are observed in the lower thoracic and lumbar vertebrae

abnormal costovertebral joint morphology ( J:60410 )

• in most newborn homozygotes, one of the most caudal ribs (R13) is abnormally fused to the pedicle of the vertebra

abnormal thoracic vertebrae morphology ( J:60410 )

• in T2, the ossification center of the vertebral body is abnormally fused to the pedicles, rather than separated from the pedicles by cartilage as in wild-type neonates

• in newborn homozygotes, the lower thoracic vertebrae are malformed and contain bilateral twin ossification centers that are prematurely fused to the pedicles

kyphoscoliosis ( J:60410 )

• at 8 weeks of age, homozygotes exhibit kyphoscoliosis, characterized by severe mediolateral and dorsoventral curvature of the spine in the thoracic and lumber region

abnormal cervical axis morphology ( J:60410 )

• in C2, both tuberculae are absent and the transverse foramina are ventrally opened with an enlarged ossification center

abnormal lumbar vertebrae morphology ( J:60410 )

• all lower lumbar vertebrae are malformed and contain bilateral twin ossification centers that are prematurely fused to the pedicles

• a split or severely notched vertebral body is observed in L4 and L5

• ~40% of newborn homozygotes display an L6 with two backward-pointing transverse processes resembling S1

• ~10% of newborn homozygotes have an L6 with one forward and one backward-pointing transverse process

abnormal sacral vertebrae morphology ( J:60410 )

• the S1 vertebra is only mildly affected with a reduced vertebral body that is barely fused with the pedicles

abnormal vertebral transverse process morphology ( J:60410 )

• ~40% of newborn homozygotes display two backward-pointing transverse processes in L6 that resembles S1

• ~10% of newborn homozygotes display one forward and one backward-pointing transverse process in L6

• the remaining 50% of homozygotes display a normal L6 with two forward-pointing transverse processes

abnormal vertebral body morphology ( J:60410 )

• newborn homozygotes display premature fusion of the vertebral body to the pedicles along the vertebral column

• a split or severely notched vertebral body is observed in L4 and L5

abnormal sternum ossification ( J:60410 )

• mutant intersternebrae are occasionally ossified leading to multiple sternebrae fusions

growth/size/body

decreased body size ( J:60410 )

• homozygotes are smaller than wild-type and heterozygous control littermates

reproductive system

reduced female fertility ( J:60410 )

♀ • female homozygotes display reduced fecundity with rare pregnancies

decreased litter size ( J:60410 )

• female homozygotes produce small litters with 4 or fewer pups/litter

respiratory system

respiratory distress ( J:60410 )

• some homozygotes have trouble breathing

craniofacial

abnormal neurocranium morphology ( J:60410 )

• newborn homozygotes display a flatter neurocranium with a snub-nosed appearance

• however, the craniofacial skeleton is overtly normal

Genotype
MGI:4437565

ht2

• Allelic Composition: kkt/kkt⁺
• Genetic Background: involves: C57BL/6 * CBA

limbs/digits/tail

kinked tail ( J:60410 )

• ~10% of heterozygotes display a mild distal undulation in the tail later in life

Genotype
MGI:4437579

cx3

• Allelic Composition: kkt/kkt⁺; Pax1^un/Pax1⁺
• Genetic Background: involves: C57BL/6 * CBA

skeleton

skeleton phenotype ( J:60410 )

N • newborns exhibit a normal sternum; no fusion of the fourth and fifth sternebrae is observed, unlike in kkt or Pax1^un homozygotes

small acromion ( J:60410 )

• newborns exhibit a severe reduction in the acromion of the scapula

abnormal axial skeleton morphology ( J:60410 )

• newborns display skeletal defects similar to those observed in Pax1^un homozygotes, but milder than in kkt homozygotes, except for the split vertebral body seen in multiple vertebrae between L2 and L5

abnormal thoracic vertebrae morphology ( J:60410 )

• all newborns exhibit bilateral ossification centers in the lower thoracic vertebrae; however, the ossification centers are not fused to the pedicles, unlike in kkt homozygotes

abnormal lumbar vertebrae morphology ( J:60410 )

• all newborns exhibit bilateral ossification centers in the lumbar vertebrae

• ossification centers are only fused to the pedicles in the lower lumbar region

• a split vertebral body is observed in multiple vertebrae between L2 and L5, and this is far more severe than in either kkt or Pax1^un homozygotes

• however, the transverse processes in L6 are all pointing forward, similar to those in wild-type control neonates

abnormal vertebral body morphology ( J:60410 )

• a split vertebral body is observed in L3, L4, and L5