Gata4 but also its paralogs Gata5 and Gata6 are required for normal heart formation in mammals (reviewed by Nemer, 2008) and human congenital cardiomyopathies are linked to mutations in the GATA4 gene, including valve and septal defects (Garg et al., 2003, Rajagopal et al., 2007). Here, GATA4 is linked to histiocytoid cardiomyopathy.