Phenotypes Associated with This Genotype

Genotype
MGI:3723120

• Allelic Composition: Nrg1^tm1Cbm/Nrg1^tm3Cbm; Isl2^tm1Arbr/Isl2⁺
• Genetic Background: involves: 129P2/OlaHsd * 129S7/SvEvBrd * C57BL/6J

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

mortality/aging

neonatal lethality, incomplete penetrance ( J:69623 )

• ~90% of mice die at birth, with phenotype similar to Nrg1^tm1Cbm homozygous embryos

nervous system

absent Schwann cells ( J:69623 )

• Schwann cells are absent from intramuscular motor axons between E13.5-E16.5

abnormal nervous system development ( J:69623 )

abnormal motor neuron morphology ( J:69623 )

• motor neurons are defasciculated and disorganized

abnormal motor neuron innervation pattern ( J:69623 )

• in developing muscle, motor axons largely retract by birth; by E18.5, motor axons and terminals are absent

abnormal neuromuscular synapse morphology ( J:69623 )

• at diaphragm synapses, band of acetylcholine receptors (AChRs) is wider (17.5% of muscle length) than in wild-type muscle (7% of muscle length)

cellular

absent Schwann cells ( J:69623 )

• Schwann cells are absent from intramuscular motor axons between E13.5-E16.5