Analysis of correlation using mean values of normalized mRNA levels revealed that the ADHD probands having the rs363504 ‘TT (t = 0.25, P = 0.53) and rs363538 ‘AA’ (t = 1.78, P = 0.08) genotypes had lower GRIK1 expression (Data not presented due to limitation in the number of samples after stratified analysis). The gene discussed is GRIK1; the disease is attention deficit-hyperactivity disorder.