Spinal muscular atrophy (SMA), a leading genetic cause of death in childhood, is caused by deletion of the SMN1 gene, located at chromosome 5q13. The molecular pathogenesis, which results in motor neuron degeneration within the anterior horn of spinal cord, is a focus of debate among scientists. The unique nature of the duplicative 5q chromosomal region provides considerable yet challenging opportunity for disease correction as well as complication in performing molecular diagnosis and understanding the molecular pathogenesis. This article reviewed recent findings in the molecular pathogenesis of SMA as well as the research advances in the molecular diagnosis and therapeutic approaches.