ADHD: Attention-Deficit/Hyperactivity Disorder; CNV: Copy Number Variation; WES: Whole-Exome Sequencing; SNP: Single Nucleotide Polymorphism; MTHFR: Methylenetetrahydrofolate Reductase; PGE2: Prostaglandin E2; IFN-γ: Interferon-gamma; ROS: Reactive Oxygen Species; NM: Not Mentioned; M: Male; F: Female Ref.: Reference. Here, MTHFR is linked to attention deficit-hyperactivity disorder.