DRD4 Gene Polymorphisms as a Risk Factor for Children with Attention Deficit Hyperactivity Disorder in Iranian Population

Table 2

Demographics of the study sample.

Index	ADHD ()	Control ()	value
Age (year)	6.883 ± 2.27	6.98 ± 2.50	0.3
Gender (boy/girl)	108/22	84/46	<0.001
Percentage of ADHD boys	83	61	0.04
Children of first-degree family marriage (%)	56	4	<0.001