Search for an epigenetic biomarker in ADHD diagnosis, based on the DAT1 gene 5’-UTR methylation. A new possible approach

Attention Deficit/Hyperactivity Disorder (ADHD) is the most common neuro-developmental alteration in childhood. To date, its diagnosis is exclusively clinical, however recent studies focused on searching for objective biomarkers. We recently reported a selective alteration of DNA methylation in the 5′-UTR of dopamine transporter (DAT1) gene, in a 1CGG2CGG3CGG and a 5CG6CG motif, for ADHD patients (compared to controls). Presently, we looked for DNA methylation of the corresponding CpG sites but complementary on the opposite strand (“COS”). Exploiting a novel cross-correlation approach, we found a core M5 - M5 COS and M2 - M2 COS relationship with relatively free M1 and M6 COS extremes. Our data might be relevant, to find a new biomarker to diagnose ADHD in affected subjects.