A mutation in Vps54 in mice (“Wobbler” mouse) which causes a destabilization of the GARP complex has been reported to cause defective spermiogenesis and motor neuron disease (Schmitt-John et al., 2005), while a Vps54 null mutation leads to embryonic lethality (Schmitt-John et al., 2005). This evidence concerns the gene VPS54 and motor neuron disorder.