Browsing by Author "Dourado, A."
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- Genome-wide scan in Portuguese Island families identifies 5q31-5q35 as a susceptibility locus for schizophrenia and psychosisPublication . Sklar, P.; Pato, Michele T.; Kirby, A. N.; Petryshen, T. L.; Medeiros, Helena; Carvalho, Célia; Macedo, António; Dourado, A.; Coelho, I.; Valente, J.; Soares, M. J.; Ferreira, Carlos Paz; Lei, M.; Verner, A.; Hudson, T. J.; Morley, C. P.; Kennedy, J. L.; Azevedo, Maria H.; Lander, E.; Daly, M. J.; Pato, Carlos N.Schizophrenia is a common psychiatric disorder with a complex genetic etiology. To understand the genetic basis of this syndrome in Portuguese Island populations, we performed a genome-wide scan of 29 families with schizophrenia, which identified a single region on 5q31-5q35 with strong linkage (NPL=3.09, P=0.0012 at D5S820). Empirical simulations set a genome-wide threshold of NPL=3.10 for significant linkage. Additional support for this locus in schizophrenia comes from higher-density mapping and mapping of 11 additional families. The combined set of 40 families had a peak NPL=3.28 (P=0.00066) at markers D5S2112-D5S820. These data and previous linkage findings from other investigators provide strong and consistent evidence for this genomic region as a susceptibility locus for schizophrenia. Exploratory analyses of a novel phenotype, psychosis, in families with schizophrenia and bipolar disorder detected evidence for linkage to the same markers as found in schizophrenia (peak NPL=3.03, P=0.0012 at D5S820), suggesting that this locus may be responsible for the psychotic symptoms observed in both diseases.
- Genome-wide scan in Portuguese Island families implicates multiple loci in bipolar disorder : fine mapping adds support on chromosomes 6 and 11Publication . Pato, Carlos N.; Pato, Michele T.; Kirby, A. N.; Petryshen, T. L.; Medeiros, Helena; Carvalho, Célia; Macedo, António; Dourado, A.; Coelho, I.; Valente, J.; Soares, M. J.; Ferreira, Carlos Paz; Lei, M.; Verner, A.; Hudson, T. J.; Morley, C. P.; Kennedy, J. L; Azevedo, Maria H.; Daly, M. J.; Sklar, P.As part of an extensive study in the Portuguese Island population of families with multiple patients suffering from bipolar disorder and schizophrenia, we performed an initial genome-wide scan of 16 extended families with bipolar disorder that identified three regions on chromosomes 2, 11, and 19 with genome-wide suggestive linkage and several other regions, including chromosome 6q, also approached suggestive levels of significance. Dick et al. [2003: Am J Hum Genet 73:107-114] recently reported in a study of 250 families with bipolar disorder a maxLOD score of 3.61 near marker D6S1021 on chromosome 6q. This study replicates this finding having detected a peak NPL = 2.02 (P = 0.025) with the same marker D6S1021(104.7 Mb). Higher-density mapping provided additional support for loci on chromosome 6 including marker D6S1021 with an NPL = 2.59 (P = 0.0068) and peaking at marker D6S1639 (125 Mb) with an NPL = 3.06 (P = 0.0019). A similar pattern was detected with higher-density mapping of chromosome 11 with an NPL = 3.15 (P = 0.0014) at marker D11S1883 (63.1 Mb). Simulations at the density of our fine mapping data indicate that less than 1 scan out of 10 would find two such scores genome-wide in the same scan by chance. Our findings provide additional support for a susceptibility locus for bipolar disorder on 6q, as well as, suggesting the importance of denser scans.
- Genomewide Linkage Analysis of Bipolar Disorder by Use of a High Density Single-Nucleotide–Polymorphism (SNP) Genotyping Assay : A Comparison with Microsatellite Marker Assays and Finding of Significant linkage to Chromosome 6q22Publication . Middleton, Frank A.; Pato, Michele T.; Gentile, Karen; Morley, C. P.; Zhao, X.; Eisener, A. F.; Brown, A.; Petryshen, T. L.; Kirby, A. N.; Medeiros, Helena; Carvalho, Célia; Macedo, António; Dourado, A.; Coelho, I.; Valente, J.; Soares, M. J.; Ferreira, Carlos Paz; Lei, M.; Azevedo, Maria H.; Kennedy, J. L.; Daly, M. J.; Sklar, P.; Pato, Carlos N.We performed a linkage analysis on 25 extended multiplex Portuguese families segregating for bipolar disorder, by use of a high-density single-nucleotide-polymorphism (SNP) genotyping assay, the GeneChip Human Mapping 10K Array (HMA10K). Of these families, 12 were used for a direct comparison of the HMA10K with the traditional 10-cM microsatellite marker set and the more dense 4-cM marker set. This comparative analysis indicated the presence of significant linkage peaks in the SNP assay in chromosomal regions characterized by poor coverage and low information content on the microsatellite assays. The HMA10K provided consistently high information and enhanced coverage throughout these regions. Across the entire genome, the HMA10K had an average information content of 0.842 with 0.21-Mb intermarker spacing. In the 12-family set, the HMA10K-based analysis detected two chromosomal regions with genomewide significant linkage on chromosomes 6q22 and 11p11; both regions had failed to meet this strict threshold with the microsatellite assays. The full 25-family collection further strengthened the findings on chromosome 6q22, achieving genomewide significance with a maximum nonparametric linkage (NPL) score of 4.20 and a maximum LOD score of 3.56 at position 125.8 Mb. In addition to this highly significant finding, several other regions of suggestive linkage have also been identified in the 25-family data set, including two regions on chromosome 2 (57 Mb, NPL = 2.98; 145 Mb, NPL = 3.09), as well as regions on chromosomes 4 (91 Mb, NPL = 2.97), 16 (20 Mb, NPL = 2.89), and 20 (60 Mb, NPL = 2.99). We conclude that at least some of the linkage peaks we have identified may have been largely undetected in previous whole-genome scans for bipolar disorder because of insufficient coverage or information content, particularly on chromosomes 6q22 and 11p11.