MYH11 (Myosin Heavy Chain 11): MYH11 is a gene that encodes a smooth muscle myosin heavy chain, a critical component of the contractile apparatus in smooth muscle cells. This protein is essential for smooth muscle contraction and relaxation, supporting important functions such as vascular regulation, gastrointestinal motility, and respiratory function. MYH11 helps maintain the structure and function of smooth muscle tissues throughout the body. Variations or mutations in this gene can lead to vascular conditions, including thoracic aortic aneurysms and dissections.