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Phenotypes Associated with This Genotype
Genotype
MGI:3844347
Allelic
Composition
Lbx1tm1Thbr/Lbx1tm1Thbr
Genetic
Background
involves: 129S4/SvJae
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Lbx1tm1Thbr mutation (0 available); any Lbx1 mutation (13 available)
phenotype observed in females
phenotype observed in males
N normal phenotype
mortality/aging
• mice with abnormal heart looping die between E9.5 and E11.5

cardiovascular system
• increased cell proliferation is seen in various regions of the heart at E14.5, E15.5, E17.5 and P0
• about 15% of mice show looping abnormalities including straight heart tubes, incomplete looping, and variable dilations along the heart tube
• enlarged coronary vessels in newborns
• a thickened interventricular septum is seen in newborns
• seen in newborns
• increase in thickness is due to hyperplasia not hypertrophy as myocyte size is similar to controls

muscle
N
• despite being derived from Lbx1+ precursor cells diaphragm and tongue muscle morphology appears normal
• migration of most lacZ expressing precursor cells is disrupted with lacZ+ cells
• ectopically distributed along the rostral caudal axis in the intermediate and lateral plate mesoderm at E10.5
• migration of precursor cells to some ventral limb muscles, tongue and diaphragm appears slightly delayed
• severe limb muscle defects
• hindlimbs contain only a few scattered myocytes
• no myotubes are detected in the dorsal part of the forelimbs, while the ventral flexor muscles are mostly present but a few are absent or reduced in size
• affected forelimb ventral muscles (m. flexor digitorum superficalis et profundi, m. opponens pollicis and m. adductor pollicic) are at the distal end of the limb
• most shoulder muscles are also missing
• remaining forelimb muscles contain fewer myofibers with enlarged myotubes containing centrally located nuclei

limbs/digits/tail
• abnormally bent morphology in newborns
• no myotubes are detected in the dorsal part of the forelimbs
• most ventral flexor muscles are present but a few are absent or reduced in size
• affected forelimb ventral muscles (m. flexor digitorum superficalis et profundi, m. opponens pollicis and m. adductor pollicic) are at the distal end of the limb
• thin compared to heterozygous littermates
• hindlimbs contain only a few scattered myocytes
• severe limb muscle defects
• hindlimbs contain only a few scattered myocytes
• no myotubes are detected in the dorsal part of the forelimbs, while the ventral flexor muscles are mostly present but a few are absent or reduced in size
• affected forelimb ventral muscles (m. flexor digitorum superficalis et profundi, m. opponens pollicis and m. adductor pollicic) are at the distal end of the limb
• most shoulder muscles are also missing
• remaining forelimb muscles contain fewer myofibers with enlarged myotubes containing centrally located nuclei

embryo
• seen in mice with abnormal heart looping

behavior/neurological
• no movement of the forelimbs is seen although spontaneous trunk movements are present
• no movement of the hindlimbs is seen although spontaneous trunk movements are present

cellular
• migration of most lacZ expressing precursor cells is disrupted with lacZ+ cells
• ectopically distributed along the rostral caudal axis in the intermediate and lateral plate mesoderm at E10.5
• migration of precursor cells to some ventral limb muscles, tongue and diaphragm appears slightly delayed


Contributing Projects:
Mouse Genome Database (MGD), Gene Expression Database (GXD), Mouse Models of Human Cancer database (MMHCdb) (formerly Mouse Tumor Biology (MTB)), Gene Ontology (GO)
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last database update
04/16/2024
MGI 6.23
The Jackson Laboratory