In clinical settings, a reduction in phosphorylation of myosin light chain 2 (MLC2) has been demonstrated in adult patients with heart failure (Sanbe et al., 1999; Davis et al., 2001; Moss and Fitzsimons, 2006; Stelzer et al., 2006; Scruggs and Solaro, 2011; Sheikh et al., 2012, 2014). The gene discussed is MYL2; the disease is heart failure.