In addition, GRIN2A rs2229193 G/G homozygotes was found to be at a higher risk of attention disorders in ADHD patients, and more omission errors associated with G allele (Kim et al., 2020), but other studies have identified the A allele as the risk factor (Barnby et al., 2005; Tarabeux et al., 2011). Here, GRIN2A is linked to attention deficit-hyperactivity disorder.