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Phenotypes associated with this allele
Allele Symbol
Allele Name
Allele ID 		Cbfbtm2.1Spe
targeted mutation 2.1, Nancy A Speck
MGI:3721277
Summary 2 genotypes
Jump to Allelic Composition Genetic Background Genotype ID
hm1
 		Cbfbtm2.1Spe/Cbfbtm2.1Spe involves: 129S4/SvJae MGI:3721308
ht2
 		Cbfbtm1Spe/Cbfbtm2.1Spe involves: 129S4/SvJae MGI:3721372


Genotype
MGI:3721308
hm1
Allelic
Composition		 Cbfbtm2.1Spe/Cbfbtm2.1Spe
Genetic
Background		 involves: 129S4/SvJae
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Cbfbtm2.1Spe mutation (0 available); any Cbfb mutation (36 available)
♀ phenotype observed in females
♂ phenotype observed in males
N normal phenotype
mortality/aging
neonatal lethality, complete penetrance ( J:124224 )
• die within the first day after birth although born at normal Mendelian ratios

skeleton
abnormal long bone diaphysis morphology ( J:124224 )
• reduced primary ossification and delayed appearance of secondary ossification centers
abnormal skeleton development ( J:124224 )
• delayed ossification of ribs, metacarpal/metatarsal bones, phalanges, pelvis, sternum, vertebrae
• hypoplastic clavicles, scapulae, calvaria, maxillae, mandibles

hematopoietic system
abnormal thymus cell ratio ( J:124224 )
• lower percentage of double positive T cells and absolute numbers reduced 10 fold
• increased levels of CD4 expressing cells
thymus hypoplasia ( J:124224 )
• small size
• reduced cellularity
abnormal T cell differentiation ( J:124224 )
• transition from early T-lineage to DN2 stage severely impaired
• DN2 to DN3 transition severely impaired
decreased double-positive T cell number ( J:124224 )
• lower percentage of double positive T cells and absolute numbers reduced 10 fold
increased CD4-positive, alpha-beta T cell number ( J:124224 )
• increased levels of CD4 expressing T cells but not typical CD4+ cells
abnormal splenic cell ratio ( J:124224 )
• 4-5 fold reduction in CD45+ numbers
• 10-20 fold reduction in monocyte/granulocytes
• CD19+ B cells and Ter119 erythrocyte numbers are reduced but proportionally normal

immune system
abnormal thymus cell ratio ( J:124224 )
• lower percentage of double positive T cells and absolute numbers reduced 10 fold
• increased levels of CD4 expressing cells
thymus hypoplasia ( J:124224 )
• reduced cellularity
• small size
abnormal T cell differentiation ( J:124224 )
• transition from early T-lineage to DN2 stage severely impaired
• DN2 to DN3 transition severely impaired
decreased double-positive T cell number ( J:124224 )
• lower percentage of double positive T cells and absolute numbers reduced 10 fold
increased CD4-positive, alpha-beta T cell number ( J:124224 )
• increased levels of CD4 expressing T cells but not typical CD4+ cells
abnormal splenic cell ratio ( J:124224 )
• 4-5 fold reduction in CD45+ numbers
• 10-20 fold reduction in monocyte/granulocytes
• CD19+ B cells and Ter119 erythrocyte numbers are reduced but proportionally normal

craniofacial

limbs/digits/tail

endocrine/exocrine glands
abnormal thymus cell ratio ( J:124224 )
• lower percentage of double positive T cells and absolute numbers reduced 10 fold
• increased levels of CD4 expressing cells
thymus hypoplasia ( J:124224 )
• small size
• reduced cellularity




Genotype
MGI:3721372
ht2
Allelic
Composition		 Cbfbtm1Spe/Cbfbtm2.1Spe
Genetic
Background		 involves: 129S4/SvJae
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Cbfbtm1Spe mutation (0 available); any Cbfb mutation (36 available)
Cbfbtm2.1Spe mutation (0 available); any Cbfb mutation (36 available)
♀ phenotype observed in females
♂ phenotype observed in males
N normal phenotype
mortality/aging
neonatal lethality, complete penetrance ( J:124224 )
• die within the first day after birth although born at normal Mendelian ratios

skeleton
abnormal long bone diaphysis morphology ( J:124224 )
• reduced primary ossification and delayed appearance of secondary ossification centers
• increased severity
abnormal skeleton development ( J:124224 )
• delayed ossification of ribs, metacarpal/metatarsal bones, phalanges, pelvis, sternum, vertebrae
• hypoplastic clavicles, scapulae, calvaria, maxillae, mandibles
• increased severity

hematopoietic system
abnormal thymus cell ratio ( J:124224 )
• lower percentage of double positive T cells and absolute numbers reduced 100 fold
• increased levels of CD4 expressing cells
thymus hypoplasia ( J:124224 )
• small size
• reduced cellularity
abnormal T cell differentiation ( J:124224 )
• transition from early T-lineage to DN2 stage severely impaired
• DN2 to DN3 transition severely impaired
decreased double-positive T cell number ( J:124224 )
• lower percentage of double positive T cells and absolute numbers reduced 100 fold
extramedullary hematopoiesis ( J:124224 )
• half the number of hematopoietic cells in the fetal liver at E12.5
• reversed at E17.5
abnormal megakaryocyte morphology ( J:124224 )
• colonies in culture are denser with smaller cells
thrombocytopenia ( J:124224 )
• reduced numbers of platelets both in culture and in the circulation
increased CD4-positive, alpha-beta T cell number ( J:124224 )
• increased levels of CD4 expressing T cells but not typical CD4+ cells
abnormal splenic cell ratio ( J:124224 )
• 4-5 fold reduction in CD45+ numbers
• 10-20 fold reduction in monocyte/granulocytes
• CD19+ B cells and Ter119 erythrocyte numbers are reduced but proportionally normal

immune system
abnormal thymus cell ratio ( J:124224 )
• lower percentage of double positive T cells and absolute numbers reduced 100 fold
• increased levels of CD4 expressing cells
thymus hypoplasia ( J:124224 )
• small size
• reduced cellularity
abnormal T cell differentiation ( J:124224 )
• transition from early T-lineage to DN2 stage severely impaired
• DN2 to DN3 transition severely impaired
decreased double-positive T cell number ( J:124224 )
• lower percentage of double positive T cells and absolute numbers reduced 100 fold
increased CD4-positive, alpha-beta T cell number ( J:124224 )
• increased levels of CD4 expressing T cells but not typical CD4+ cells
abnormal splenic cell ratio ( J:124224 )
• 4-5 fold reduction in CD45+ numbers
• 10-20 fold reduction in monocyte/granulocytes
• CD19+ B cells and Ter119 erythrocyte numbers are reduced but proportionally normal

craniofacial

limbs/digits/tail

endocrine/exocrine glands
abnormal thymus cell ratio ( J:124224 )
• lower percentage of double positive T cells and absolute numbers reduced 100 fold
• increased levels of CD4 expressing cells
thymus hypoplasia ( J:124224 )
• small size
• reduced cellularity




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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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Send questions and comments to User Support. 		last database update
04/23/2024
MGI 6.23 		The Jackson Laboratory