Phenotypes Associated with This Genotype

Genotype
MGI:2675319

• Allelic Composition: Nbn^tm1Xu/Nbn^tm1Xu
• Genetic Background: Not Specified

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

mortality/aging

increased mortality induced by gamma-irradiation ( J:75272 )

• homozygotes all die by 10 days after gamma-irradiation while controls survive for at least 2 months

growth/size/body

decreased body weight ( J:75272 )

• body weight is 77% of that of controls

postnatal growth retardation ( J:75272 )

immune system

thymus hypoplasia ( J:75272 )

• thymus cellularity is about 30% of that of controls

decreased mature B cell number ( J:75272 )

• reduction in mature B cells in the peripheral lymphoid organs

decreased pre-B cell number ( J:75272 )

• reduction in the numbers of B220+IgM- pre-B cells

decreased T cell number ( J:75272 )

• reduction in mature T cells in the peripheral lymphoid organs

decreased CD4-positive, alpha-beta T cell number ( J:75272 )

• more than 5-fold reduction in the number of CD4+ thymocytes

abnormal cell-mediated immunity ( J:75272 )

• severely defective in the T-dependent antibody response, however IgG levels are normal indicating no defects in class switching in B cells

reproductive system

absent oocytes ( J:75272 )

♀ • ovaries lack any oocytes

absent ovarian follicles ( J:75272 )

♀

ovary degeneration ( J:75272 )

♀ • ovaries are degenerated

female infertility ( J:75272 )

♀ • females are sterile, however males are fertile and have normal spermatogenesis

cellular

absent oocytes ( J:75272 )

♀ • ovaries lack any oocytes

abnormal cell cycle ( J:75272 )

• MEFs are impaired in G1/S transition during cellular proliferation

• ES cells undergo prolonged G2 accumulation and increased radio-resistant DNA synthesis after gamma-irradiation

increased cellular sensitivity to gamma-irradiation ( J:75272 )

• ES cells are hypersensitive to gamma-irradiation

decreased fibroblast proliferation ( J:75272 )

• MEFs proliferate slower than controls with a lower saturation density and undergo premature senescence at high passage

neoplasm

increased T cell derived lymphoma incidence ( J:75272 )

• lymphomas are mostly of CD4+CD8+ immature thymocyte origin and are composed of large sized lymphoblasts

hematopoietic system

thymus hypoplasia ( J:75272 )

• thymus cellularity is about 30% of that of controls

decreased mature B cell number ( J:75272 )

• reduction in mature B cells in the peripheral lymphoid organs

decreased pre-B cell number ( J:75272 )

• reduction in the numbers of B220+IgM- pre-B cells

decreased T cell number ( J:75272 )

• reduction in mature T cells in the peripheral lymphoid organs

decreased CD4-positive, alpha-beta T cell number ( J:75272 )

• more than 5-fold reduction in the number of CD4+ thymocytes

endocrine/exocrine glands

thymus hypoplasia ( J:75272 )

• thymus cellularity is about 30% of that of controls

absent ovarian follicles ( J:75272 )

♀

ovary degeneration ( J:75272 )

♀ • ovaries are degenerated

increased T cell derived lymphoma incidence ( J:75272 )

• lymphomas are mostly of CD4+CD8+ immature thymocyte origin and are composed of large sized lymphoblasts

nervous system

nervous system phenotype ( J:75272 )

N • no abnormalities in the development of the CNS and no microencephaly

homeostasis/metabolism

increased mortality induced by gamma-irradiation ( J:75272 )

• homozygotes all die by 10 days after gamma-irradiation while controls survive for at least 2 months

Mouse Models of Human Disease		DO ID	OMIM ID(s)	Ref(s)
Nijmegen breakage syndrome		DOID:7400	OMIM:251260	J:75272