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Phenotypes associated with this allele
Allele Symbol
Allele Name
Allele ID 		Hba-a1+
wild type
MGI:2430985
Summary 6 genotypes
Jump to Allelic Composition Genetic Background Genotype ID
ht1
 		Hba-a1tm1Led/Hba-a1+ involves: 129S6/SvEvTac MGI:2679486
ht2
 		Hba-a1tm1Led/Hba-a1+ involves: 129S6/SvEvTac * NIH Black Swiss MGI:2679487
ht3
 		Hba-a1tm1Ywk/Hba-a1+ involves: 129X1/SvJ * C57BL/6J MGI:2679510
ht4
 		Hba-a1tm1Shs/Hba-a1+ involves: C57BL/6CrSlc MGI:3762583
cx5
 		Hba-a1tm1Led/Hba-a1+
Hba-xtm1Led/Hba-x+ 		involves: 129S6/SvEvTac * NIH Black Swiss MGI:2679489
cx6
 		Hba-a1tm1Ywk/Hbath-J involves: 129X1/SvJ * C57BL/6J MGI:4453797


Genotype
MGI:2679486
ht1
Allelic
Composition		 Hba-a1tm1Led/Hba-a1+
Genetic
Background		 involves: 129S6/SvEvTac
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Hba-a1tm1Led mutation (1 available); any Hba-a1 mutation (5 available)
♀ phenotype observed in females
♂ phenotype observed in males
N normal phenotype
hematopoietic system
abnormal hemoglobin ( J:41934 )
• reduced hemoglobin concentration




Genotype
MGI:2679487
ht2
Allelic
Composition		 Hba-a1tm1Led/Hba-a1+
Genetic
Background		 involves: 129S6/SvEvTac * NIH Black Swiss
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Hba-a1tm1Led mutation (1 available); any Hba-a1 mutation (5 available)
♀ phenotype observed in females
♂ phenotype observed in males
N normal phenotype
hematopoietic system
abnormal hemoglobin ( J:41934 )
• reduced hemoglobin concentration




Genotype
MGI:2679510
ht3
Allelic
Composition		 Hba-a1tm1Ywk/Hba-a1+
Genetic
Background		 involves: 129X1/SvJ * C57BL/6J
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Hba-a1tm1Ywk mutation (0 available); any Hba-a1 mutation (5 available)
♀ phenotype observed in females
♂ phenotype observed in males
N normal phenotype
hematopoietic system
anemia ( J:35018 )
• heterozygotes are borderline anemic relative to wild-type controls
• however, heterozygotes are not hemolytic, as shown by normal reticulocyte counts
decreased mean corpuscular volume ( J:35018 )
• heterozygotes display a borderline reduction in MCV, similar to that sometimes seen in human silent carriers, indicating a mild alpha-thalassemia phenotype




Genotype
MGI:3762583
ht4
Allelic
Composition		 Hba-a1tm1Shs/Hba-a1+
Genetic
Background		 involves: C57BL/6CrSlc
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Hba-a1tm1Shs mutation (0 available); any Hba-a1 mutation (5 available)
♀ phenotype observed in females
♂ phenotype observed in males
N normal phenotype
hematopoietic system
anemia ( J:81902 )
• mild anemia
abnormal hemoglobin ( J:81902 )
• the oxygen dissociation of red blood cells shows low affinity for oxygen in vitro

homeostasis/metabolism
increased carbon dioxide production ( J:81902 )
• produce more carbon dioxide in room air and hypoxic conditions
increased oxygen consumption ( J:81902 )
• consume more oxygen in room air and hypoxic conditions
• consume more oxygen in skeletal muscles by oxidative phosphorylation
hyperoxia ( J:81902 )
• enhanced tissue oxygenation
increased aerobic running capacity ( J:81902 )
• run 2.5 times as far as wild-type mice spontaneously on a running wheel

muscle
abnormal skeletal muscle fiber type ratio ( J:81902 )
• show no fiber hypertrophy or atrophy
• on histochemical staining for ATPase, show a higher percentage of type IIA fibers and a lower percentage of type IIB fibers in deep regions of the muscle

cellular
abnormal aerobic respiration ( J:81902 )
• succinate dehydrogenase activities in both type IIA and type IIB muscle fibers are greater in deep regions of the tibialis anterior compared to wild-type mice




Genotype
MGI:2679489
cx5
Allelic
Composition		 Hba-a1tm1Led/Hba-a1+
Hba-xtm1Led/Hba-x+
Genetic
Background		 involves: 129S6/SvEvTac * NIH Black Swiss
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Hba-a1tm1Led mutation (1 available); any Hba-a1 mutation (5 available)
Hba-xtm1Led mutation (1 available); any Hba-x mutation (10 available)
♀ phenotype observed in females
♂ phenotype observed in males
N normal phenotype
hematopoietic system
abnormal hemoglobin ( J:41934 )
• reduced hemoglobin concentration




Genotype
MGI:4453797
cx6
Allelic
Composition		 Hba-a1tm1Ywk/Hbath-J
Genetic
Background		 involves: 129X1/SvJ * C57BL/6J
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Hba-a1tm1Ywk mutation (0 available); any Hba-a1 mutation (5 available)
Hbath-J mutation (2 available); any Hba mutation (11 available)
♀ phenotype observed in females
♂ phenotype observed in males
N normal phenotype
mortality/aging
perinatal lethality, complete penetrance ( J:35018 )
• mutants do not survive as newborns

growth/size/body
decreased fetal size ( J:35018 )
• at E19.5, mutant fetuses are smaller than control fetuses

hematopoietic system
hemolytic anemia ( J:35018 )
• at E17.5, mutant fetuses display severe hemolytic anemia
abnormal erythrocyte morphology ( J:35018 )
• at E17.5, mutant erythrocytees display notable anisocytosis, poikilocytosis, polychromasia, and targeting, characteristic of severe thalassemia
• virtually all mutant erythrocytes exhibit hemoglobin H inclusions
abnormal hemoglobin ( J:35018 )
• at E17.5, hemoglobin H (beta4) is the major component constituting 55%-65% of total hemoglobin, as shown by isoelectric focusing electrophoresis
reticulocytosis ( J:35018 )
• at E17.5, mutant fetuses exhibit very high reticulocyte counts

integument
pallor ( J:35018 )
• at E19.5, mutant fetuses are paler than control fetuses




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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Send questions and comments to User Support. 		last database update
01/13/2026
MGI 6.24 		The Jackson Laboratory