Phenotypes Associated with This Genotype

Genotype
MGI:6508400

• Allelic Composition: Spg21^tm1Mchan/Spg21^tm1Mchan
• Genetic Background: Not Specified

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

behavior/neurological

limb grasping ( J:302080 )

• in the hind limb clasp test, 6-month old mice splay their hind limbs inwardly and grasp solid objects and 12-month old mice have about 2 times higher hind limb clasping

impaired coordination ( J:302080 , J:302256 )

• 12-month old mice exhibit a higher number of foot slippages than 6-month old mice on a beam walk test (J:302080)

• the mean latency to fall in the ledge test is shorter in both 6- and 12-month old mice compared to wild-type mice, with 12-month old mice showing greater difficulty walking along the ledge and slipping and falling about 2 times more than wild-type mice (J:302080)

• in the narrow beam-walking test, mice exhibit an increase in the number of slips as early as 2-6 months of age and after 12 months of age, mice show progressive difficulty in traversing the beam, with a delay in completing the task (J:302256)

abnormal locomotor behavior ( J:302256 )

• mice show slight dragging of the hind limbs at several months of age which progressively worsens with age

cellular

abnormal neuron differentiation ( J:302080 )

• cortical neurons grown on poly-D-lysine-coated plates show only marginal changes in morphology during the first 3 days and show reduced rate of formation of ganglial networks at 96 hours, indicating reduced growth of cortical neurons

• cortical neurons fail to respond to EGF-induced growth and maturation

• however, proliferation rate of cortical neurons in response to EGF is similar to wild-type neurons

nervous system

abnormal neuron morphology ( J:302080 , J:302256 )

• cortical neurons grown on poly-D-lysine-coated plates show a reduction in the number of neurons with axonal branches (J:302080)

• cortical neurons form fewer branches per axon (J:302080)

• cerebral cortical neurons grown on glass cover slips show increased axonal branching (J:302256)

• however, the number of primary dendrites is unchanged and axon elongation is normal and mice show no evidence of white matter disease (J:302256)

abnormal neuron differentiation ( J:302080 )

• cortical neurons grown on poly-D-lysine-coated plates show only marginal changes in morphology during the first 3 days and show reduced rate of formation of ganglial networks at 96 hours, indicating reduced growth of cortical neurons

• cortical neurons fail to respond to EGF-induced growth and maturation

• however, proliferation rate of cortical neurons in response to EGF is similar to wild-type neurons

abnormal axon morphology ( J:302080 )

• axonal termini of cortical neurons appear as fringed or feathered with minute processes

• however, axonal length of cortical neurons does not differ from wild-type neurons

Mouse Models of Human Disease		DO ID	OMIM ID(s)	Ref(s)
Mast syndrome		DOID:0060245	OMIM:248900	J:302256