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Phenotypes associated with this allele
Allele Symbol
Allele Name
Allele ID
Hoxb8tm1.1Mrc
targeted mutation 1, Mario R Capecchi
MGI:2159735
Summary 2 genotypes
Jump to Allelic Composition Genetic Background Genotype ID
hm1
Hoxb8tm1.1Mrc/Hoxb8tm1.1Mrc involves: 129S1/Sv * 129X1/SvJ MGI:2673421
hm2
Hoxb8tm1.1Mrc/Hoxb8tm1.1Mrc involves: 129S1/Sv * 129X1/SvJ * C57BL/6 * SJL MGI:4818890


Genotype
MGI:2673421
hm1
Allelic
Composition
Hoxb8tm1.1Mrc/Hoxb8tm1.1Mrc
Genetic
Background
involves: 129S1/Sv * 129X1/SvJ
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Hoxb8tm1.1Mrc mutation (0 available); any Hoxb8 mutation (3 available)
phenotype observed in females
phenotype observed in males
N normal phenotype
behavior/neurological
• spend almost twice as much time grooming compared to controls, initiate grooming more frequently, spend excessive time on body licking and biting which leads to hair loss, and excessively groom cagemates, however forelimb clasping, motor control and rearing are normal
• spend on average one hour less time sleeping than controls

skeleton
N
• no defects in the formation of the first rib are detected

nervous system
N
• no defects either in formation or maintenance of the dorsal root ganglia

integument
• varied hair loss showing large bald patches on lateral and ventral body surfaces due to excessive grooming
• self-inflicted skin lesions due to excessive grooming, with thickened epidermis in hairless patches of older mice, however observe no inflammation in the area and no defect in cutaneous sensation

Mouse Models of Human Disease
OMIM ID Ref(s)
Trichotillomania; TTM 613229 J:73745




Genotype
MGI:4818890
hm2
Allelic
Composition
Hoxb8tm1.1Mrc/Hoxb8tm1.1Mrc
Genetic
Background
involves: 129S1/Sv * 129X1/SvJ * C57BL/6 * SJL
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Hoxb8tm1.1Mrc mutation (0 available); any Hoxb8 mutation (3 available)
phenotype observed in females
phenotype observed in males
N normal phenotype
behavior/neurological
• hair removal in mutants is done with teeth rather than paw scratching; time spent engaged in scratching behavior is similar between controls and most mutants
• mutants spend about twice as much time in grooming in a 24 hour period compared to controls
• lidocaine treatment of mutants does not alter overgrooming, indicating that behavior is not result of response to chronic itching
• mutants have significantly greater latency time in response to heat
• nociceptive defect is not rescued by transplantation of wild-type bone marrow into irradiated mutants

nervous system
• a 15% reduction in the total number of microglia is observed in homozygotes compared to controls
• disorganization and reduction in numbers of input sensory fibers and of interneurons in laminae I and II are detected
• in adult animals, significant decrease in neuronal cell body numbers is detected relative to wild-type controls

immune system
• a 15% reduction in the total number of microglia is observed in homozygotes compared to controls

hematopoietic system
• a 15% reduction in the total number of microglia is observed in homozygotes compared to controls

integument
• mutants have significantly greater latency time in response to heat
• nociceptive defect is not rescued by transplantation of wild-type bone marrow into irradiated mutants
• hair removal progresses along ventral surface and extends to lateral surfaces with excessive grooming
• result from excessive grooming on ventral surface of body and extending to lateral surfaces





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last database update
09/27/2016
MGI 6.05
The Jackson Laboratory