To prevent or treat vascular injuries in patients with HHcy, including the MTHFR C677T population, the cystathionine-β-synthase (CBS)-deficient population, hypertensive patients with HHcy, and abdominal aortic aneurysm patients with HHcy, Hcy-induced AT1 receptor activation should be taken into consideration. This evidence concerns the gene AGTR1 and abdominal aortic aneurysm.