Phenotypes Associated with This Genotype

Genotype
MGI:3614637

• Allelic Composition: Agrn^nmf380/Agrn^nmf380
• Genetic Background: C57BL/6J-Agrn^nmf380/J

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

mortality/aging

premature death ( J:176117 )

• mice die after a few weeks to a few months of age

behavior/neurological

abnormal motor capabilities/coordination/movement ( J:176117 )

• poor hindlimb motor control

limb grasping ( J:87349 )

• when lifted by its tail, a mutant mouse keeps its hind limbs close to its body

tremors ( J:87349 )

• homozygous mutant mice exhibit intense body tremor both during movement and when at rest

impaired limb coordination ( J:87349 )

• the hind limbs of homozygous mice often move together

paraparesis ( J:87349 )

• mutants' hind limbs appear weak, remaining low during locomotion

muscle

abnormal skeletal muscle fiber type ratio ( J:176117 )

• at P20, mice exhibit increased type 1 slow muscle fibers in the gastrocnemius compared with wild-type mice

skeletal muscle atrophy ( J:176117 )

• Background Sensitivity: more severe on a C57BL/6J or DBA background than on other backgrounds

muscle spasm ( J:87349 )

• homozygous mutants experience brief spasms of the front and/or hind limbs

myopathy ( J:87349 )

• cross sections of axial muscle from 3 mutant mice ages 27 - 34 days revealed neurogenic myopathy; atrophied, denervated muscle fibers and small, regenerating fibers exist among normal-appearing muscle fibers

nervous system

nervous system phenotype ( J:176117 )

N • mice exhibit normal axon numbers and size

abnormal neuromuscular synapse morphology ( J:176117 )

• mice exhibit abnormal neuromuscular junctions (NMJs) morphology with smaller, simpler postsynaptic sites than in wild-type mice

• diaphragm NMJs are abnormal at birth, severly affected at P4, and virtually completely degraded by P14 compared to in wild-type mice

• NMJ defects arise by P13 in the triangularis sterni with pre- and postsynaptic degradation at P18

• tibialis anterior NMJs are disaggregated by P14 compared to in wild-type mice

• NMJ postnatal degradation varies in different muscles

• however, mice do not exhibit die-back neuropathy

growth/size/body

decreased body size ( J:87349 , J:176117 )

limbs/digits/tail

camptodactyly ( J:87349 )

• homozygotes' toes, particularly those of the hind paws, may not extend fully

abnormal hindlimb morphology ( J:176117 )

• hindlimb atrophy

Mouse Models of Human Disease		DO ID	OMIM ID(s)	Ref(s)
congenital myasthenic syndrome 8		DOID:0110657	OMIM:615120	J:176117