Archived Guthrie blood spots as a novel source for quantitative DNA methylation analysis.

Sodium bisulfite treatment followed by PCR and DNA sequencing is widely considered the gold standard for the analysis of DNA methylation patterns. However, this technique generally requires substantial quantities of genomic DNA as starting material and is often associated with degradation of DNA. Here, we assess the feasibility of performing bisulfite sequencing on DNA isolated from 3-mm diameter punches of dried blood Guthrie spots. We demonstrate that it is possible to perform bisulfite sequencing from both freshly prepared and archived dried blood spots, using a combination of high purity DNA extraction and efficient bisulfite conversion. With the number of new technologies available for DNA methylation studies, we have extended this analysis and have successfully used a high-throughput mass spectrometry method for DNA methylation analysis on these samples. This provides a new source of material for epigenetic analysis of birth samples and provides an invaluable reference point to track temporal change in epigenetic profiles possibly linked with health and disease.