PDE5A (Phosphodiesterase 5A): PDE5A is a gene that encodes an enzyme specifically targeting cyclic GMP (cGMP), a key second messenger in various biological processes. PDE5A plays a crucial role in regulating vascular smooth muscle, and its inhibitors are commonly used to treat erectile dysfunction and pulmonary hypertension. Research on PDE5A is important for cardiovascular and urogenital health.