Historically, most candidate genes for AD/HD were selected based on their involvement in neurotransmission. In this analysis, we elected to perform a candidate gene study, but chose an alternative approach for defining AD/HD candidate genes, focusing on genes located at cytogenetic breakpoints that have been associated with AD/HD-like phenotypes. Our candidate gene selection was based on a report of a family that cosegregates a pericentric inversion with an early onset developmental condition, characterized by impulsive behavior and intellectual deficit (De Silva et al., 2003; Efron et al., 2003). A total of eight children, four with and four without the inversion, were clinically evaluated. Children with the inversion exhibited more signs of conduct problems, hyperactive-impulsive tendencies, and learning problems according to the Conners’ Parent Rating Scale (CPRS) (Efron et al., 2003). In addition, the mean intelligence quotient (IQ) was significantly lower (P=0.03) among individuals with the inversion compared with individuals without the inversion (Efron et al., 2003). At the time the De Silva et al. (2003) and Efron et al. (2003) manuscripts were published, the inversion breakpoints were described as being
