Phenotypes Associated with This Genotype

Genotype
MGI:3036892

• Allelic Composition: Hbb-b1^tm1Unc/Hbb-b1⁺; Hbb-b2^tm1Unc/Hbb-b2⁺
• Genetic Background: involves: 129P2/OlaHsd * C57BL/6J

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

growth/size/body

decreased body weight ( J:30155 )

• F1 and F2 heterozygotes are significantly smaller

increased spleen weight ( J:30155 )

• the spleen weight to body weight ratio is significantly greater in heterozygotes

hematopoietic system

anemia ( J:30155 , J:88672 )

• at 7 weeks, mutants have a decreased red blood cell count with variation in the shape and inequality in the size (many microcytes and occasional polychromatic macrocytes) of the red blood cells (J:30155)

• hematopoietic stem cells from heterozygotes transfected with a large fragment of the human beta globin gene and injected back into the heterozygote restored red blood cell counts to normal (J:88672)

increased bone marrow cell number ( J:30155 )

• heterozygotes have increased bone marrow cellularity and increased numbers of megakaryocytes and erythroid precursors

decreased hematocrit ( J:30155 )

decreased hemoglobin content ( J:30155 )

• red blood cells are generally hypochromic

increased nucleated erythrocyte cell number ( J:30155 )

• nucleated red blood cells are found

reticulocytosis ( J:30155 )

• reticulocyte counts are increased 21-fold

abnormal spleen morphology ( J:30155 , J:88672 )

• erythroid hyperplasia (J:30155)

• megakaryocytes are present (J:30155)

• iron particles are present in the macrophages in the centers of areas of erythropoiesis (J:30155)

• hematopoietic stem cells from heterozygotes transfected with a large fragment of the human beta globin gene and injected back into the heterozygote restored normal spleen morphology (J:88672)

increased spleen weight ( J:30155 )

• the spleen weight to body weight ratio is significantly greater in heterozygotes

intermingled spleen red and white pulp ( J:30155 )

• there is no clear distinction between the red and white pulp

decreased spleen white pulp amount ( J:30155 )

• the white pulp is almost completely replaced by hematopoietic tissue

homeostasis/metabolism

increased circulating bilirubin level ( J:30155 )

• serum concentrations of total and indirect bilirubin are elevated in mice 6 to 7 weeks old

hemosiderosis ( J:30155 , J:88672 )

• older (5-6 months) heterozygotes have iron accumulation in the proximal convoluted tubules of the kidney, and hepatocytes and Kupffer cells in the liver a sign of hemosiderosis (J:30155)

• hematopoietic stem cells from heterozygotes transfected with a large fragment of the human beta globin gene and injected back into the heterozygote reduced abnormal iron accumulations (J:88672)

immune system

abnormal spleen morphology ( J:30155 , J:88672 )

• erythroid hyperplasia (J:30155)

• megakaryocytes are present (J:30155)

• iron particles are present in the macrophages in the centers of areas of erythropoiesis (J:30155)

• hematopoietic stem cells from heterozygotes transfected with a large fragment of the human beta globin gene and injected back into the heterozygote restored normal spleen morphology (J:88672)

increased spleen weight ( J:30155 )

• the spleen weight to body weight ratio is significantly greater in heterozygotes

intermingled spleen red and white pulp ( J:30155 )

• there is no clear distinction between the red and white pulp

decreased spleen white pulp amount ( J:30155 )

• the white pulp is almost completely replaced by hematopoietic tissue

limbs/digits/tail

abnormal femur morphology ( J:30155 )

• heterozygotes have a longer zone of proliferation and a shorter zone of osteogenesis

skeleton

abnormal femur morphology ( J:30155 )

• heterozygotes have a longer zone of proliferation and a shorter zone of osteogenesis

decreased compact bone thickness ( J:30155 )

integument

pallor ( J:30155 )

• heterozygotes are pale at birth

Mouse Models of Human Disease		DO ID	OMIM ID(s)	Ref(s)
beta thalassemia		DOID:12241	OMIM:613985	J:30155