This gene encodes a protein that reduces cell growth by stimulating apoptosis. Alternative splicing and the use of alternative promoters result in multiple transcript variants encoding the same protein. This gene is imprinted in brain where different transcript variants are expressed from each parental allele. Transcript variants initiating from the upstream promoter are expressed preferentially from the maternal allele, while transcript variants initiating downstream of the interspersed NNAT gene (GeneID:4826) are expressed from the paternal allele. Transcripts at this locus may also undergo A to I editing, resulting in amino acid changes at three positions in the N-terminus of the protein. [provided by RefSeq, Nov 2015]