To test whether HDAC6 constitutes a necessary factor for pulmonary hypertension (PH) development, wild-type (Hdac6Y/+) and Hdac6 knockout mice (Hdac6Y/−) were exposed to either normoxia or hypoxia (10% O2) for 3 weeks. The gene discussed is HDAC6; the disease is pulmonary arterial hypertension.