NAIP (Neuronal Apoptosis Inhibitory Protein), also known as BIRC1, is a 153-kDa member of the inhibitor of apoptosis (IAP) protein family. NAIP contains three baculovirus IAP repeat (BIR) domains and a unique nucleotide-binding domain. It contains no RING finger motif. NAIP inhibits apoptosis induced by a variety of mechanisms. The spinal muscular atrophies (SMAs) are among the most common autosomal recessive disorders associated with an absence of the NAIP gene.