PPARGC1A and attention deficit-hyperactivity disorder: There was a significant difference in the methylation ratio of the PPARGC1A promoter region among ADHD subtypes (p = 0.030; inattentive subtype 0.17 ± 0.09, hyperactive–impulsive subtype 0.12 ± 0.03, combined subtype 0.23 ± 0.12, not-otherwise specified subtype 0.20 ± 0.12).