BROOKES,
K., Xu,
X., Chen, W., Zhou, K., Neale, B., Lowe, N., Anney, R., Franke, B.,
Gill, M., Ebstein, R. P., Buitelaar, J., Sham, P., Cambell, D., Knight,
J., Andreou, P., Altink, M., Arnold, R., Boer, F., Buschgens, C., Butler,
L., Christiansen,
H., Feldman,
L., Fleischman, K., Fliers, E., Howe-Forbes, R., Goldfarb, A., Heise,
A., Gabriels, I, Korn-Lubetzki, I., Johansson,
L.,
Marco, R., Medad, S., Minderaa, R. B.,
Mulas, F., Müller, U. C., Mulligan, A., Rabin, K., Rommelse, N.,
Sethna, V., Sorohan, J., Uebel, H., Psychogiou, L., Weeks, A., Barrett,
R., Craig, I., Banaschewski, T., Sonuga-Barke, E. J. S., Eisenberg,
J., Kuntsi, J., Manor, I., McGuffin, P., Miranda, A.,
Oades, R. D.,
Plomin, R., Roeyers, H., Rothenberger, A., Sergeant, J. A., Steinhausen,
H-C., Taylor, E. A., Thompson, M., Faraone, S. V., & Asherson, P. Introduction: ADHD is a common neurodevelopmental disorder. It starts in early childhood & can persist into adulthood in many cases. Family & twin studies have demonstrated the importance of genetic factors & candidate gene association studies have identified several loci that exert small but significant effects on ADHD. Four genome linkage scans-have pointed to moderately large effects of loci on 5p, 6q, 7p, 11q, 12q & 17p chromosomal regions. To provide further clarification of reported associations & identify novel-associated genes, we examined 915 SNPs spanning 52 candidate genes involved in the regulation of neurotransmitter pathways, particularly DA, NA & 5HT pathways, in addition to circadian rhythm (& clock) genes. Methods:
-- Analysis used
within family tests of association in a sample of 674 families
with 776 DSM-IV combined type cases ascertained for the
International Multi-centre Genetics project (IMAGE) -- 93.5% were male,
mean age was 11.2y, (5-17y) for cases & siblings (n=808). Association
tests were the transmission disequilibrium test implemented by UNPHASED
& WHAP programmes ((www.hgmp.mrc.ac.uk/Registered/Options/unphased.html).
SNP genotyping (1536 SNPs in original-array) used the Illumina high-throughput
"Bead Array" technology. Yet, we must conclude that -- Further studies will be needed to confirm or refute the observed associations & their generalizability to other samples. |