La polyarthrite rhumatoïde (PR) et la maladie coronaire (MC) sont deux maladies touchant l'adulte comportant une susceptibilité génétique et partageant plusieurs chapitres physiopathologiques. Nous avons recherché des gènes de susceptibilité à la PR en employant une approche gène-candidat dans des loci suggerés par les données d'études de criblage du genome. Nous avons mis au point une étude originale (Genescaf) d'approche des gènes impliqués dans la MC. / Rhumatoid arthritis (RA) and coronary artery disease (CAD) are two adult diseases involving some genetic susceptibility genes and sharing many physiopathogenic chapters. We tried to find some RA susceptibility genes by a candidate-gene approach located in linked loci. We performed an original study (Genescaf) to approach some CAD susceptibility genes.

Bipolar disorder and recurrent major depression are complex psychiatric illnesses with a substantial, yet unknown genetic component. Genetic studies have identified linkage of bipolar disorder and recurrent major depression with markers on chromosome 4p15-p16 in a large Scottish family and three smaller families. To focus the search for genetic factors for susceptibility to illness two approaches were adopted: a chromosome 4p15-p16 candidate gene study and a whole-genome linkage scan. In the first instance, phosphatidylinositol 4-kinase type-II beta (PI4K2B) was selected as a candidate gene. Analysis of haplotypes in the four linked families identified two regions, both of which were shared by three families. PI4K2B lies within one of these regions. PI4K2B is also a worthy functional candidate as it is a member of the phosphatidylinositol pathway, which is targeted by lithium for therapeutic effect in bipolar disorder. Expression studies at the allele-specific mRNA and protein level were performed in lymphoblastoid cell lines from the large Scottish family. There was no evidence for expression differences between affected and non-affected family members. However, a case-control association study showed preliminary evidence for association of schizophrenia but not bipolar disorder, with tagging single nucleotide polymorphisms from the PI4K2B genomic region. Second, the linkage evidence for bipolar disorder and recurrent major depression in the large Scottish family was re-examined. This was important because additional family members had been recruited and advances in technology made it feasible to cover all chromosome regions more densely than had been possible ten years ago. Stringent genotyping and pedigree error checks were performed to ensure an optimised dataset for analysis. Furthermore, the large family was divided in an informative manner for ease of analysis using both parametric and non-parametric methods, supplemented by haplotype analysis. Genome-wide significant evidence for linkage was observed on chromosome 4p15- p16 and genome-wide suggestive evidence was observed on chromosomes 8p21 and 1p36. The analysis clearly supports the evidence for a susceptibility locus of bipolar disorder and recurrent major depression on chromosome 4p15-p16, while identifying other genetic loci that may confer risk to psychiatric illness.

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Objective: To determine whether genotype at the catechol-O-methyltransferase rs4680, dopamine D2 receptor rs1800497, serotonin receptor 1A rs6295 or serotonin transporter 5-HTTLPR single nucleotide polymorphisms is associated with response to citalopram and escitalopram treatment in patients with major depressive disorder and generalized anxiety disorder. Methods: Twenty one patients with depression or anxiety who were treated with citalopram or escitalopram for greater than one year, and who stopped the medication for a period of time during which their symptoms returned, and upon re-commencing the medication their symptoms were again reduced, were classified as responders. Patients were assessed using the Sheehan Disability Scale and the Quick Inventory of Depressive Symptomology- self report. The control group consisted of 146 healthy participants. Genotype was determined at each of the candidate genes studied: catechol-O-methyltransferase, dopamine D2 receptor, serotonin receptor 1A and serotonin transporter. Chi squared tests were used to compare genotypic and allele frequencies between responders and controls. Results: There was no significant difference in genotypic or allele frequencies between responders and controls at each of the genes analyzed. Conclusions: This pilot study suggests that genotype at the catechol-O-methyltransferase, dopamine D2 receptor, serotonin receptor 1A and serotonin transporter genes is not associated with response to citalopram and escitalopram treatment in patients with depression and anxiety. A larger sample size, along with a genome-wide scan are needed to identify genetic variants that predict medication response in future patients. / Thesis (Master, Neuroscience Studies) -- Queen's University, 2010-08-31 12:26:21.402

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Introduction: The purpose of this study was to examine phenotypic expression of craniofacial form, shape, and size as it relates to the genotype of an individual. Shape analyses were completed on 3-D images of each subject's craniofacial structure by landmarking 45 points of interest on the cranial base, facial bones, and upper and lower jaws. A candidate gene analysis was undertaken focusing on specific genes in the Hippo Signaling Pathway to examine genotype-phenotype correlations that play a role in craniofacial development. This study is a continuation of a larger project aimed at the identification of candidate genes associated with human dento-skeletal bite problems led by Dr. Lina Moreno-Uribe. Methods: The sample size for our study included 166 individuals who had never been treated orthodontically at the time of records. Each individual was genotyped and a CBCT of the craniofacial complex was captured. Each CBCT image was landmarked by a single observer using 45 points to mark points on the cranial base and facial bones including the maxilla and mandible. General Procrustes superimposition was used to find correlations with phenotype and genotype. Size analysis was completed with average Euclidean Distances and ANOVA analysis. Results: 2 SNP's from the FOX03 gene had significant associations with size. The AA genotyped individuals appeared larger in overall size than AB genotyped individuals. 3 SNP's had statistically significant associations with facial form. The FOX06 SNPs had significant associations with increased anterior-posterior growth of the maxilla. The AJUBA SNP had significant associations with increased overall craniofacial breadth. Conclusion: Genes in the Hippo signaling pathway have specific roles in the development of facial form and size.

Salt stress is a global problem that limits agricultural production. The early responses to salinity, independent of toxic shoot-ion accumulation, are still largely unknown. Here, optimised salt treatment and high-throughput phenotyping protocols were developed and used to examine the natural variation in the early responses to salt stress of 191 Arabidopsis thaliana accessions. Common and novel traits of plants grown under salt treatment were captured through time using RGB and chlorophyll fluorescence imaging. Phenotypic data was combined with the Arabidopsis 10M SNP markers for genome-wide association studies to identify genetic components underlying the early responses to salt stress. The most promising candidate loci were selected based on association strength, allele frequency and number of traits associating to the same locus. In silico analysis highlighted interesting allelic variations across the identified loci, and by phenotypically characterising the candidate gene mutants under salt stress, the associations were experimentally validated. This work comprises a detailed study of the natural variation in the early responses to salt stress, which can give insights into the mechanisms contributing to salinity tolerance and provide the fundaments for crop improvements under saline conditions across the globe.

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