INS and type 1 diabetes mellitus: Another study [27] primarily tested downstream CpG sites (located at + 255, + 273, + 303, + 329, + 364, + 370, + 396 and + 399) within the coding region of the insulin gene and confirmed increased levels of unmethylated cfDNA in patients with T1D as well as subjects with increased risk of T1D [28].