Showing papers by "Thordur Sigmundsson published in 2007"
TL;DR: The inverse correlation of the variant with iron stores is consistent with the suspected involvement of iron depletion in the pathogenesis of the disease and is associated with susceptibility to periodic limb movements in sleep.
Abstract: Background The restless legs syndrome (RLS) is a common neurologic disorder characterized by an irresistible urge to move the legs. It is a major cause of sleep disruption. Periodic limb movements in sleep are detectable in most patients with RLS and represent an objective physiological metric. Methods To search for sequence variants contributing to RLS, we performed a genomewide association study and two replication studies. To minimize phenotypic heterogeneity, we focused on patients with RLS who had objectively documented periodic limb movements in sleep. We measured serum ferritin levels, since iron depletion has been associated with the pathogenesis of RLS. Results In an Icelandic discovery sample of patients with RLS and periodic limb movements in sleep, we observed a genomewide significant association with a common variant in an intron of BTBD9 on chromosome 6p21.2 (odds ratio, 1.8; P=2×10–9). This association was replicated in a second Icelandic sample (odds ratio, 1.8; P=4×10–4) and a U.S. sample...
560 citations
TL;DR: It is concluded that genetic predisposition to schizophrenia reduces performance even during a task placing minimal cognitive load on working memory and perceptual processing, suggesting impaired vigilance.
83 citations
TL;DR: The results are in general agreement with the previous report, with the strongest association signal observed in a region upstream of the AHI1 gene.
Abstract: Recently, markers in the Abelson Helper Integration Site 1 (AHI1) region were shown to be associated with schizophrenia in a family sample of Israeli-Arabs. Here, we report a study evaluating the relevance of the AHI1 region to schizophrenia in an Icelandic sample. Seven markers shown to confer risk in the previous report were typed in 608 patients diagnosed with broad schizophrenia and 1504 controls. Odds ratios for the overtransmitted alleles in the Israeli-Arab families ranged from 1.15 to 1.29 in the Icelandic sample. After Bonferroni correction for the seven markers tested, two markers were significantly associated with schizophrenia. Thus, our results are in general agreement with the previous report, with the strongest association signal observed in a region upstream of the AHI1 gene.
49 citations
TL;DR: The findings confirm the existence of robust oculomotor deficits in schizophrenia in a large sample and can be used as valid endophenotypes in future studies of potential schizophrenia risk genotypes in the genetically homogenous Icelandic population.
1 citations