Spinal muscular atrophy (SMA) is an autosomal recessive neurodegenerative disease characterized by loss of anterior horn cells in the spinal cord and concomitant symmetrical muscle weakness and atrophy . SMA is caused by deletion or mutations of the survival motor neuron (SMN1) gene. SMA patients lack a functional SMN1 gene,but they possess an intact SMN2 gene,which though nearly identical to SMN1,is only partially functional . A large majority of SMN2 transcripts lack exon 7,resulting in production of a truncated,less stable SMN protein . The level of SMN protein correlates with phenotypic severity of SMA. This antibody,raised against the C-ternimal region (275-294aa) encoded by the exon 7.