NPPB and Abnormal heart morphology: The atria and ventricles express nppa and nppb during development (Zeller et al., 1987; Chien et al., 1991; Cameron et al., 1996), Nppa marks differentiating myocardium and is a sensitive marker for congenital heart malformations (Christoffels et al., 2000; Bruneau, 2011).