R-loop's are found with H3K9me2 mark at FXN in Friedreich's ataxia cells. H3K9me2 is present at a subset of cardiovascular disease-associated gene promoters in vascular smooth muscle cells to block binding of NFκB and AP-1 (activator protein-1) transcription factors. Reduced levels of H3K9me2 have been observed in vascular smooth muscle cells from human atherosclerotic lesions compared to healthy aortic tissue in patients. Vascular smooth muscle cells from diabetic patients display reduced levels of H3K9me2 compared to non-diabetic controls; it has therefore been suggested that dysregulation of H3K9me2 might underlie the vascular complications associated with diabetes. Loss of H3K9me2 in vascular smooth muscle cells exacerbates upregulation of a subset of cardiovascular disease-associated genes in vascular disease models. Histone modifications, including H3K9me2, can be detected using a variety of methods: