ALDH7A1 and Huntington disease: Irregardless of the source of cGMP tone, pharmacotherapies such as PDE inhibitors designed to target and normalize the function of these signaling pathways are of high clinical significance for treating motor and cognitive symptoms in patients with HD (Wild and Tabrizi, 2014; Mrzljak and Munoz-Sanjuan, 2015; Puigdellivol et al., 2016).