NAIP (Neuronal Apoptosis Inhibitor Protein) is a member of the IAPs (Inhibitor of Apoptosis Proteins) that function in cell death pathways to inhibit apoptosis. NAIP was discovered based on its association with a neurodegenerative disorder. Mutations and deletions in the NAIP gene locus is a contributing factor in spinal muscular atrophy. Coexpression of NAIP and hippocalcin protects neurons against calcium-induced cell death. NAIP is strongly expressed in anterior horn and motor cortex neurons of the normal brain. It is also found in human fetal neurons and in adult choroid plexus cells.