Attention deficit-hyperactivity disorder (ADHD) is the most common childhood-onset behavioral disorder, affecting approximately 5 to 10% of children and adolescents (Wolraich et al., 1996). In this condition, persistent inattention and/or hyperactive-impulsive behavior results in impaired social and/or academic functioning. Boys are affected about 8 times more frequently than girls (Zametkin et al., 1990).
Genetic Heterogeneity of Attention Deficit-Hyperactivity Disorder
Susceptibility to ADHD7 (613003) is conferred by variation in the TPH2 gene (607478) on chromosome 12q21. ADHD8 (619957) is caused by mutation in the CDH2 gene (114020) on chromosome 18q12.
Several loci for susceptibility to ADHD have been mapped, including ADHD1 (608903) on chromosome 16p13, ADHD2 (608904) on chromosome 17p11, ADHD3 (608905) on chromosome 6q12, ADHD4 (608906) on chromosome 5p13, ADHD5 (612311) on 2q21.1, and ADHD6 (612312) on 13q12.11. Also see MOLECULAR GENETICS. [from
OMIM]