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Phenotypes associated with this allele
Allele Symbol
Allele Name
Allele ID 		Nfkbiatm1Bal
targeted mutation 1, David Baltimore
MGI:1858084
Summary 3 genotypes
Jump to Allelic Composition Genetic Background Genotype ID
hm1
 		Nfkbiatm1Bal/Nfkbiatm1Bal involves: 129S4/SvJae * C57BL/6J MGI:3034093
cx2
 		Nfkbiatm1Bal/Nfkbiatm1Bal
Nfkbietm1Syme/Nfkbietm1Syme 		involves: 129P2/OlaHsd * 129S4/SvJae * C57BL/6 * DBA/2 MGI:3053046
cx3
 		Nfkb1tm1Bal/Nfkb1tm1Bal
Nfkbiatm1Bal/Nfkbiatm1Bal 		involves: 129S4/SvJae * C57BL/6J MGI:3034094


Genotype
MGI:3034093
hm1
Allelic
Composition		 Nfkbiatm1Bal/Nfkbiatm1Bal
Genetic
Background		 involves: 129S4/SvJae * C57BL/6J
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Nfkbiatm1Bal mutation (1 available); any Nfkbia mutation (19 available)
♀ phenotype observed in females
♂ phenotype observed in males
N normal phenotype
mortality/aging
postnatal lethality, complete penetrance ( J:30058 )
• death occurred around the 1st week of age

growth/size/body
decreased body size ( J:30058 )
• although of normal size at birth, homozygotes became noticeably smaller than normal by 3-4 days of age
• by 7 days of age homozygotes were severely runted (1/3 normal weight)

hematopoietic system
abnormal granulocyte differentiation ( J:30058 )
• elevated numbers of granulocyte precursors in bone marrow and spleen as animals age
thymus atrophy ( J:30058 )
• atrophy in mice over 6 days of age
increased leukocyte cell number ( J:30058 )
• 3 fold increase in peripheral WBC count - about 95% neutrophils
spleen atrophy ( J:30058 )
• small size by day 2 with a worsening size reduction until death

immune system
abnormal granulocyte differentiation ( J:30058 )
• elevated numbers of granulocyte precursors in bone marrow and spleen as animals age
thymus atrophy ( J:30058 )
• atrophy in mice over 6 days of age
increased leukocyte cell number ( J:30058 )
• 3 fold increase in peripheral WBC count - about 95% neutrophils
spleen atrophy ( J:30058 )
• small size by day 2 with a worsening size reduction until death

integument
abnormal epidermis stratum basale morphology ( J:30058 )
• poorly defined basal layer
flaky skin ( J:30058 )
• significant sloughing

cellular
abnormal granulocyte differentiation ( J:30058 )
• elevated numbers of granulocyte precursors in bone marrow and spleen as animals age

endocrine/exocrine glands
thymus atrophy ( J:30058 )
• atrophy in mice over 6 days of age




Genotype
MGI:3053046
cx2
Allelic
Composition		 Nfkbiatm1Bal/Nfkbiatm1Bal
Nfkbietm1Syme/Nfkbietm1Syme
Genetic
Background		 involves: 129P2/OlaHsd * 129S4/SvJae * C57BL/6 * DBA/2
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Nfkbiatm1Bal mutation (1 available); any Nfkbia mutation (19 available)
Nfkbietm1Syme mutation (0 available); any Nfkbie mutation (22 available)
♀ phenotype observed in females
♂ phenotype observed in males
N normal phenotype
mortality/aging
neonatal lethality, complete penetrance ( J:88142 )
• double homozygotes are born alive but remain cyanotic and die within 10-30 minutes

hematopoietic system
increased B cell apoptosis ( J:88142 )
• increased among B cells
increased T cell apoptosis ( J:88142 )
• increased among T cells in transition from double positive to single positive
abnormal B cell differentiation ( J:88142 )
• decreased numbers of B cell precursors
decreased immature B cell number ( J:88142 )
• very low numbers of immature B cells
abnormal T cell differentiation ( J:88142 )
• development from the double positive stage to the single positive stage is reduced
decreased pre-B cell number ( J:88142 )
• clear reduction of B220+CD43- cells

immune system
increased B cell apoptosis ( J:88142 )
• increased among B cells
increased T cell apoptosis ( J:88142 )
• increased among T cells in transition from double positive to single positive
abnormal B cell differentiation ( J:88142 )
• decreased numbers of B cell precursors
decreased immature B cell number ( J:88142 )
• very low numbers of immature B cells
abnormal T cell differentiation ( J:88142 )
• development from the double positive stage to the single positive stage is reduced
decreased pre-B cell number ( J:88142 )
• clear reduction of B220+CD43- cells

cellular
increased B cell apoptosis ( J:88142 )
• increased among B cells
increased T cell apoptosis ( J:88142 )
• increased among T cells in transition from double positive to single positive




Genotype
MGI:3034094
cx3
Allelic
Composition		 Nfkb1tm1Bal/Nfkb1tm1Bal
Nfkbiatm1Bal/Nfkbiatm1Bal
Genetic
Background		 involves: 129S4/SvJae * C57BL/6J
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Nfkb1tm1Bal mutation (3 available); any Nfkb1 mutation (104 available)
Nfkbiatm1Bal mutation (1 available); any Nfkbia mutation (19 available)
♀ phenotype observed in females
♂ phenotype observed in males
N normal phenotype
mortality/aging
postnatal lethality, complete penetrance ( J:30058 )
• survival prolonged until 2-4 weeks




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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
09/30/2025
MGI 6.24 		The Jackson Laboratory