MSX1: ProductsMSX1 (Msh homeobox homology 1) is a member of the muscle segment homoebox gene family. MSX1 is involved in limb-pattern formation, craniofacial development, odontogenesis, and tumor growth inhibition. MSX1 functions as a transcriptional repressor. MSX1 has been shown to interact with the linker histone, H1B, and repress transcription of the MyoD promoter. Chromosomal abnormalities involving MSX1 have been associated with the Wolf-Hirschhorn syndrome characterized by heart defects and mental retardation.