DNA methylation was measured using the PyroMark MD system (Qiagen) as described previously.12 (link) Oligonucleotide primers for the nearby miR-137 CpG island published previously16 (link) were purchased from Thermo Fisher Scientific. Primer sequences for the distal CpG island of miR-137 in the P1 and P2 regions are given in Supplementary Table 2. Methylation was quantified using the software provided (Qiagen).