A method for treating a subject suffering from a motor neuron degenerative disorder is provided herein, the method including: administering to the subject one or more modified adeno-associated virus (AAV) gene delivery vectors packaging a recombinant AAV (rAVV)-based genome, wherein each AAV vector is engineered to include a cDNA insert selected from a ciliary neutrophic factor receptor alpha (CNTFRa) cDNA insert, a cardiotrophin-like cytokine factor 1 (CLC) cDNA insert, and a cytokine receptor-like factor 1 (CLF) cDNA insert. Also provided are pharmaceutical compositions including one or more modified AAV gene delivery vectors, each AAV vector packaging a rAAV genome engineered to include (i) a cDNA insert selected from CNTFRa, CLC, and CLF; and (ii) a promoter; and a pharmaceutically acceptable excipient.