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 an important role in regulating vascular smooth muscle, and its inhibitors are commonly used to treat erectile dysfunction and pulmonary hypertension. Research on PDE5A is significant for cardiovascular and urogenital health.