Phenotypes Associated with This Genotype

Genotype
MGI:2675315

• 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