We measured methylation status of individual CpG loci in the 5′ regulatory region of FADS2, FADS1 (which encodes D5d) and elongase (ELOVL)-5 and ELOVL2 (which encode elongase 5 and elongase 2, respectively) in DNA extracted from peripheral blood mononuclear cells (PBMCs) isolated from patients with chronic renal disease. Here, FADS2 is linked to chronic kidney disease.