Phenotypes Associated with This Genotype

Genotype
MGI:5318856

• Allelic Composition: Smn1^tm1Cdid/Smn1^tm1Cdid; Grm7^{Tg(SMN2)89Ahmb}/Grm7⁺
• Genetic Background: involves: 129 * C57BL/6 * FVB

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

mortality/aging

postnatal lethality, complete penetrance ( J:183080 )

• median survival is 7 days

nervous system

abnormal innervation pattern to muscle ( J:183080 )

• significant decrease in the number of fully innervated motor endplates and increase in the number of partially innervated and denervated endplates in the intercostal muscle

• however, innervation of the endplates in the triangularis sterni muscle is similar to controls

abnormal neuromuscular synapse morphology ( J:183080 )

• increase in intercostal muscle homogeneous motor endplates and decrease in the number of endplates containing secondary structure

• however, endplates in the triangularis sterni muscle are similar to controls

• decrease in the number of glutamatergic excitatory synapses at P5 in the L2-L5 region of the spinal cord

abnormal spinal cord morphology ( J:183080 )

• decrease in the number of glutamatergic excitatory synapses at P5 in the L2-L5 region of the spinal cord

• significant loss in average MNs per ventral horn is seen in cervical, thoracic, and lumbar spinal cords

decreased motor neuron number ( J:183080 )

• significant loss in average MNs per ventral horn is seen in cervical, thoracic, and lumbar spinal cords

motor neuron degeneration ( J:183080 )

• signs of neurodegeneration in the intercostal muscle

decreased single cell response threshold ( J:183080 )

• threshold voltage in motor neurons is significantly lower and amplitude of the persistent inward current is significantly larger indicating increased excitability in cultured motor neurons

• high frequency of postsynaptic potentials in cultured motor neurons

cardiovascular system

decreased heart rate ( J:183080 )

• by P3 and declines over time

prolonged PR interval ( J:183080 )

• at P3-P7

prolonged QRS complex duration ( J:183080 )

• at P3-P7

prolonged QT interval ( J:183080 )

• at P3-P7

behavior/neurological

abnormal motor capabilities/coordination/movement ( J:183080 )

• decreased motor function

impaired righting response ( J:183080 )

• never develop the ability to right when placed on the back

paralysis ( J:183080 )

• near complete paralysis by P5

growth/size/body

decreased body weight ( J:183080 )

• at P2 or later

Mouse Models of Human Disease		DO ID	OMIM ID(s)	Ref(s)
Werdnig-Hoffmann disease		DOID:13137	OMIM:253300	J:183080