9783939069379_leseprobe

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Internationales Symposium (S-001-1 bis S-001-4) S-001-1 Internationales Symposium Integrating Neuroscience and Child Psychiatry Vorsitz:

B. Herpertz-Dahlmann, RWTH Aachen, Kinder- und Jugendpsychiatrie und - psychotherapie K. Konrad, Lehr- und Forschungsgebiet Klinische Neuropsychologie RWTH Aachen, Kinderund Jugendpsychiatrie und - psychotherapie

0001 Recent molecular genetic findings in ADHD Johannes Hebebrand, Rheinische Kliniken Essen, Universität Duisburg/Essen, Kinder- und Jugendpsychiatrie und - psychotherapie Friedel, S., Hinney, A., Dempfle, A., Saar, K., Sauer, S. Pre iously, we had reported a genome wide scan for attention-deficit/hyperacti ity disorder (ADHD) in 02 affected sibs of German ancestry; the highest multipoint LOD score of 4.75 was obtained on chromosome 5p (parametric HLOD analysis under a dominant model) harbouring the dopamine transporter gene (DAT ). We genotyped 0 single nucleotide polymorphisms (SNPs) in this candidate gene and its 5´region in 29 families (including the 02 initial families) with 52 affected offspring. We found that: a) SNP rs46 79 was significantly associated with ADHD upon correction for multiple testing (p= 0.0046); b) the global p- alue for association of haplotypes was significant for block two upon correction for all (n= ) tested blocks (p=0.0048); c) within block two we detected a nominal p = 0.0000 4 for one specific marker combination. This CGC haplotype showed relati e risks of .95 and 2.4 for heterozygous and homozygous carriers, respecti ely; d) finally, our linkage data and the genotype-IBD sharing test (GIST) indicated that genetic ariation at the DAT locus explains.

0002 Neuroimaging in ADHD Sarah Durston, University of Utrecht, Child & Adolescent Psychiatry, Niederlande Attention Deficit Hyperacti ity Disorder (ADHD) is a pre alent neuropsychiatric disorder with onset in childhood. Perhaps the best established cogniti e deficit associated with this disorder is problems with cogniti e control, or the ability to flexibly adapt beha ior. This is exemplified by stop- and go no/go-tasks, where performance is often impaired for affected indi iduals. These deficits are associated with atypical patterns of brain acti ation, including decreased acti ity in inferior prefrontal areas that are critical to this ability. This presentation will discuss studies focusing on the neurobiology of ADHD using functional and anatomical MRI approaches. In our pre ious work, we ha e shown that unaffected siblings of subjects with ADHD also display decreases in prefrontal acti ation and cortical gray matter olume. These findings suggest that anatomical and functional MR measures may be suitable as an intermediate phenotype for studies in estigating gene effects in ADHD. We ha e recently used this approach to in estigate the effects of two genes that are implicated in ADHD. Two genes were selected from meta-analyses, and as they ha e regionally specific expression patterns in the brain. The genes were the gene for the dopamine 4-receptor (DRD4) and the gene for the dopamine transporter (DAT ). The DRD4 gene is preferentially expressed in the prefrontal cortex, whereas DAT is preferentially expressed in the striatum. Their influence on MR measures of brain structure and acti ation was in estigated. We showed that the DAT gene preferentially influences caudate olume, whereas the DRD4 gene preferentially influences prefrontal gray matter olume. Furthermore, the DAT gene affected acti ation in the striatum. This demonstrates that some of the genes implicated in ADHD do indeed affect brain struc-

Abstracts_V04.indd 3

27.02.2007 10:30:24 Uhr


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