1,721,131 research outputs found
Genotypic association between dopamine transporter gene polymorphisms and schizophrenia
No full textDopamine transporter (DAT) gene variants do not appear to provide widespread contributions to the etiology of schizophrenia spectrum disorders, according to linkage studies [Persico et al., 1995: Am J Psychiatry 152:134-136]. They may, however, produce modifying effects, more readily detectable in specific subpopulations of schizophrenics through associations analyses. We therefore compared polymorphic DAT gene variable number tandem repeat (VNTR) distributions in 84 controls and 147 patients, divided according to DSM-IIIR schizophrenia type criteria. No evidence of allelic association between DAT alleles and schizophrenia or any specific schizophrenia subtype was found. Interestingly, the DAT genotype distribution among schizophrenic patients did display a statistically significant departure from the genotype distribution found in controls. Such discrepancies may represent stigmata of assortative mating or may suggest a "modifying" contribution of homozygote DAT genotypes to pathogenetic processes underlying schizophrenia
The structure of DSM-III-R schizotypal personality disorder diagnosed by direct interviews. Schizophrenia Bulletin, 23 (1) 83-92, 1997
No full textGenetic variants of dopamine receptor D4 and psychopathology
No full textThere is much evidence to indicate that the dopamine receptor D4 (DRD4) gene is involved in psychiatric disorders. We investigated the correlation between DRD4 gene polymorphism and the psychopathology of major psychoses, independently of diagnoses. Some 461 inpatients affected by major psychoses were assessed by the Operational Criteria checklist for psychotic illness and typed for DRD4 variants. The four symptomatologic factors-mania, depression, delusion, and disorganization-were used as phenotype definitions, DRD4 Exon 3 long allele variants were associated with high delusional scores, with the most significant difference between alleles 2 and 7 (p = 0.004). DRD4 variants may, therefore, constitute a liability factor for development of delusional symptomatology in patients with major psychoses. ZR 0 ZS 0 Z8 1 ZB 2
Increased concentrations of various amino acids in schizophrenic patients. Evidence for heterozygosity effects?
No full textThe hypothesis is examined that heterozygosity for amino acid disorders (AAD) is a genetic component of susceptibility for schizophrenic psychoses. To detect possible heterozygotes, urinary and blood amino acid levels were analyzed in a sample of subjects with a diagnosis of schizophrenia and in their biological parents and compared with those of a sample of healthy volunteers. The results showed increased blood and urinary levels of certain amino acid in those patients who have at least one parent with the same amino acid abnormality. This finding points to the possibility of heterozygosity for AAD in schizophrenic patients
Evolutionarily recent retrotransposons contribute to schizophrenia
Full text linkTransposable elements (TEs) are mobile genetic elements that constitute half of the human genome. Recent studies suggest that polymorphic non-reference TEs (nrTEs) may contribute to cognitive diseases, such as schizophrenia, through a cis-regulatory effect. The aim of this work is to identify sets of nrTEs putatively linked to an increased risk of developing schizophrenia. To do so, we inspected the nrTE content of genomes from the dorsolateral prefrontal cortex of schizophrenic and control individuals and identified 38 nrTEs that possibly contribute to the emergence of this psychiatric disorder, two of them further confirmed with haplotype-based methods. We then performed in silico functional inferences and found that 9 of the 38 nrTEs act as expression/alternative splicing quantitative trait loci (eQTLs/sQTLs) in the brain, suggesting a possible role in shaping the human cognitive genome structure. To our knowledge, this is the first attempt at identifying polymorphic nrTEs that can contribute to the functionality of the brain. Finally, we suggest that a neurodevelopmental genetic mechanism, which involves evolutionarily young nrTEs, can be key to understanding the ethio-pathogenesis of this complex disorder
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Mitochondrial variability in the Mediterranean area: a complex stage for human migrations
No full textContext: The Mediterranean area has always played a significant role in human dispersal due to the large number of migratory events contributing to shape the cultural features and the genetic pool of its populations.
Objective: This paper aims to review and diachronically describe the mitogenome variability in the Mediterranean population and the main demic diffusions that occurred in this area over time.
Methods: Frequency distributions of the leading mitochondrial haplogroups have been geographically and chronologically evaluated. The variability of U5b and K lineages has been focussed to broaden the knowledge of their genetic histories.
Results: The mitochondrial genetic makeup of Palaeolithic hunter-gatherers is poorly defined within the extant Mediterranean populations, since only a few traces of their genetic contribution are still detectable. The Neolithic lineages are more represented, suggesting that the Neolithic revolution had a marked effect on the peopling of the Mediterranean area. The largest effect, however, was provided by historical migrations.
Conclusion: Although the mitogenome variability has been widely used to try and clarify the evolution of the Mediterranean genetic makeup throughout almost 50 000 years, it is necessary to collect whole genome data on both extinct and extant populations from this area to fully reconstruct and interpret the impact of multiple migratory waves and their cultural and genetic consequences on the structure of the Mediterranean populations
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