The present invention provides a non-human animal (e.g., a mouse) that contains a plurality of genetically modified somatic cells (e.g., a motor neuron) having an exon 8 related loss-of-function modification in all WFS1 alleles. The present invention also provides a non-human animal that contains a plurality of genetically modified somatic cells having an expression cassette containing a reporter gene functionally linked to a WFS1 expression regulatory nucleic acid sequence. In addition, the present invention provides a variety of genetically modified cells and WFS1-related nucleic acids and compositions (including pharmaceutical compositions) containing the same. Also provided are methods for treating or preventing a motor neuron associated disorder (e.g., ALS), methods for identifying a modulator of WFS1 expression, methods for identifying a mimic agent of WFS1, methods for identifying a modulator of WFS1 in a motor neuron and methods for validating an animal model for a motor neuron associated disorder (e.g., ALS).