Abstract：Objective: To investigate the effect of 48 bp 2-repeat allele (2R) in exon 3 of dopamine D4 receptor (DRD4) gene on visual function network in children with attention deficit hyperactivity disorder (ADHD) and its association with clinical symptoms. Methods: According to the DRD4 genotypes, 62 cases of noncarriers of 2R genotype and 41 cases of carriers of 2R genotype were divided into two groups. The visual level of continuous attention and response control were assessed by integrated visual and audio continuous performance test, and the severity of symptoms assessed by SNAP-IV. Three brain networks related to visual function were isolated by data-driven whole brain analysis, an independent component analysis, with further group analysis and inter-group comparison made thereafter. Results: The right temporal-occipital lobe of the lateral visual network of 2R carriers was prone to enhanced functional connectivity, while the right anterior central gyrus showed decreased connectivity and right anterior cingulate gyrus prone to decreased connectivity; the right superior occipital gyrus of the medial visual network of 2R carriers was prone to enhanced connectivity, while the left superior cerebellar gyrus prone to decreased connectivity. In the right temporal-occipital lobe, SNAP inattention scores were positively correlated with the intensity of functional connectivity in 2R carriers (r=0.339, P=0.037) and negatively correlated with the intensity of functional connectivity in 2R non-carriers (r=-0.308, P=0.016).Conclusion: DRD4 2R gene may promote the development of ADHD inattention symptom by mediating the pattern of visual network changes.
