This gene encodes transcription factor 4, a basic helix-loop-helix transcription factor. The encoded protein recognizes an Ephrussi-box ('E-box') binding site ('CANNTG') - a motif first identified in immunoglobulin enhancers. This gene is broadly expressed, and may play an important role in nervous system development. Defects in this gene are a cause of Pitt-Hopkins syndrome. In addition, an intronic CTG repeat normally numbering 10-37 repeat units can expand to >50 repeat units and cause Fuchs endothelial corneal dystrophy. Multiple alternatively spliced transcript variants that encode different proteins have been described.,TCF4,E2-2,FECD3,ITF-2,ITF2,PTHS,SEF-2,SEF2,SEF2-1,SEF2-1A,SEF2-1B,SEF2-1D,TCF-4,bHLHb19,TCF4,Epigenetics & Nuclear Signaling,Transcription Factors,Stem Cells,TCF4