Mutations in several of the transcription factor genes discussed above—NKX2-5, IRX4, HEY2, and COUP-TFII—have been implicated in causing certain types of congenital heart disease (CHD), which can include defects in the size, shape, or structure of the cardiac chambers [91,92,93,94,95,96,97]. This evidence concerns the gene IRX4 and congenital heart disease.