Transcription factors are proteins that bind DNA adjacent to genes and control the production of mRNA transcripts. Scleraxis (basic helix-loop-helix transcription factor scleraxis) is a 201 amino acid protein that dimerizes with another bHLH protein to initiate transcription. Scleraxis is known to play a role in formation of mesoderm and somite-derived chondrogenic lineages. Scleraxis localizes to the nucleus and contains 1 bHLH domain. bHLH transcription factors, in general, function in cellular differentiation, proliferation, and oncogene regulation. The gene encoding Scleraxis maps to human chromosome 8, which consists of nearly 146 million base pairs, houses more than 800 genes and is associated with a variety of diseases and malignancies. Schizophrenia, bipolar disorder, Trisomy 8, Pfeiffer syndrome, congenital hypothyroidism, Waardenburg syndrome and some leukemias and lymphomas are thought to occur as a result of defects in specific genes that map to chromosome 8.