HAND2 and Tetralogy of Fallot: In humans, HAND2 was strongly expressed in the heart, and patients with genomic deletions or duplications that involved chromosome 4q33, the locus of HAND2, were susceptible to CHD, including VSD, tetralogy of Fallot (TOF), pulmonary atresia, and coarctation of the aorta (Russell et al. 1998).