In the current study, through individual assessment of channel-wise oxy-Hb signal changes using fNIRS, we successfully identified ROIs in the right IFG and MFG optimal for differentiating ADHD children from typically developing children; adaptation of well-formed formulae to the two CHs to form optimized ROIs achieved a 90% sensitivity for diagnostic predictions in individual subjects. The gene discussed is GSTM1; the disease is attention deficit-hyperactivity disorder.