This gene is a member of a gene family which encodes proteins with a basic helix-loop-helix domain. Other members of this gene family encode proteins which function as transcription factors, either enhancing or inhibiting transcription depending on the activity of other DNA binding proteins. The coding region of this gene is located entirely within the terminal exon. The encoded protein may be involved in the survival of neurons. Multiple alternatively spliced variants, encoding the same protein, have been identified. May play a role in the control of cellular aging and survival. Highly expressed in brain. Not expressed in lung or liver. Down-regulated in brain from patients suffering from Alzheimer disease.