Structural analysis of glycans associated with ADHD. A, Glycan peak DG7 isolated by HPLC from the control glycan pool. This peak consists of two structures: A2FG2 and M7, which both elute at 26 min. B, Analysis of DG7 from control glycan pool following digestion with α(1–3,4) fucosidase that converts A2FG2 to A2G2. The new peak eluted at 23.75 min, contrary to M7 structure, which remained on the original of DG7 peak. C, Analysis of DG7 from ADHD glycan pool following digestion with α(1–3,4) fucosidase. Comparison of panels B and C clearly reveals that in ADHD there is an increase of the relative ratio of A2FG2 compared with M7.