HAND1 is a member of the basic helix-loop-helix family of transcription factors. HAND1 is one of two HAND proteins， two closely related family members that are irregularly expressed in the emerging ventricular chambers and have a key part in cardiac morphogenesis. Operating in a complementary manner， they work in the development of the right ventricle and aortic arch arteries， implicating them as mediators of congenital heart disease. Furthermore， HAND1 is obligatory for early trophoblast differentiation.
