The present invention provides, inter alia, methods and pharmaceutical compositions for treating or ameliorating an effect of proximal spinal muscular atrophy (SMA) and methods for preventing or slowing motor neuron death in a subject having SMA. The methods include administering to a subject in need thereof a modulator of a gene selected from the group consisting of phosphodiesterase 1c (Pde1c), Calbindin 2 (Calb2), Egl nine homolog 3 (Eg13), Metabotropic glutamate receptor 8 (mGluR8), Syn aptotagmin 1 (Syt1), CUGBP, Elav-like family member 4 (Celf4), and combinations thereof in an amount effective to treat or ameliorate an effect of SMA. Also provided are methods for preventing or slowing motor neuron death.