Table 3: Frequency of variable number of tandem repeats (VNTR) in exon 3 of the DRD4 gene in Iranian children.

Number of repeatsADHD groupControl group value
NumberPercentageNumberPercentage

2R32.396.9>0.05
3R43.11612.3>0.05
4R9976.27053.80.004
5R96.9129.2>0.05
6R86.2118.5>0.05
7R75.4129.2>0.05