Two published studies examined the potentiality of peripheral blood global DNA methylation as a biomarker of AUDs. Bonsch et al.50 analyzed the relationship among global DNA methylation (determined by restriction digestion using methylation-sensitive endonucleases), plasma homocysteine, and AUDs in a case-control sample (90 AUD cases and 89 healthy controls). They observed a significant increase (by 10%) of global DNA methylation in AUD subjects who had elevated levels of homocysteine. Kim et al.51 evaluated methylation levels of repetitive element Alu in peripheral blood DNAs of 135 AUD patients and 150 healthy control subjects. They reported significantly higher methylation levels of Alu in AUD patients compared to healthy controls.
