Proximal spinal muscular atrophy (SMA) is a leading genetic cause of Infant death Patients with SMA lose alpha-motor neurons in the ventral horn of the spinal cord which leads to skeletal muscle weakness and atrophy SMA is the result of reduction In Survival Motor Neuron (SMN) expression Transgenic mouse models of SMA have been generated and are extremely useful in understanding the mechanisms of motor neuron degeneration in SMA and in developing new therapeutic candidates for SMA patients Several research groups have reported varying average lifespans of SMN Delta 7 SMA rnice (SMN2(+/+),SMN Delta 7(+/+),mSmn(-/-)), the most commonly used mouse model for preclinical therapeutic candidate testing One environmental factor that varied between research groups was maternal diet In this Study, we compared the effects of two different commercially available rodent chows (PicoLab2O Mouse diet and Harlan-Teklad 22/5 diet) oil the survival and motor phenotype of the SMN Delta 7 mouse model of SMA Specifically, the PicoLab20 diet significantly extends the average lifespan of the SMN Delta 7 SMA mice by approximately 25% and improved the motor phenotype as compared to the Harlan diet. These findings indicate that maternal diet alone can have considerable impact on the SMA phenotype. (C) 2009 Elsevier Inc. All rights reserved.