SNAP25 and attention deficit-hyperactivity disorder: Moreover, variants within the miR-183-96-182 cluster locus or in the miR-641 binding sites at SNAP25 gene have been associated with ADHD and impulsivity, respectively.15, 16 In addition, a recent study reported altered circulating levels of miRNAs in ADHD subjects and suggested that miR-107 levels below a certain threshold were highly predictive and specific for ADHD.17