This domain family is found in eukaryotes, and is approximately 80 amino acids in length. The family is found C-terminal to Pfam:PF00010. There is a single completely conserved residue W that may be functionally important. Neuronal basic helix-loop-helix (bHLH) transcription factors such as neuroD and neurogenin have been shown to play important roles in neuronal development.

1: A class of neuroD-related basic helix-loop-helix transcription factors expressed in developing central nervous system in zebrafish. Liao J, He J, Yan T, Korzh V, Gong Z; DNA Cell Biol. 1999;18:333-344. PMID:10235116