SMNDC1 gene is a paralog of SMN1 gene, which encodes the survival motor neuron protein, mutations in which are cause of autosomal recessive proximal spinal muscular atrophy. SMNDC1 is a nuclear protein that has been identified as a constituent of the spliceosome complex. SMNDC1 gene is differentially expressed, with abundant levels in skeletal muscle, and may share similar cellular function as the SMN1 gene. SMNDC1 is necessary for spliceosome assembly. Its overexpression causes apoptosis.