Three of the genes in the SRF regulon are represented on clinical gene panels for thoracic aortic aneurysms with dissection ((22) MYLK, MYH11, and ACTA2), suggesting that attrition of the SRF regulon with increasing age may set the stage for aneurysm initiation or progression. The gene discussed is ACTA2; the disease is thoracic aortic aneurysm.