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Identification de biomarqueurs génétiques de réponse à la venlafaxine dans une cohorte de patients déprimés

Abstract : Introduction: Major Depressive Disorder (MDD) represents an issue of Public Health. Currently, different antidepressant (AD) treatments exist, but 60% of depressed patients do not respond sufficiently to this type of treatment. Pharmacogenetics (PG) represents the study of the variability of response to a treatment associated to genetic variations identified in pharmacokinetic and pharmacodynamic genes. Personalized medicine is using PG to make the best therapeutic choice for a depressed patient. Venlafaxine (VEN), AD frequently used in psychiatry, is metabolized by the enzymes of Cytochromes P450 (CYP) 2D6 and 2C19. VEN increases the turnover of cerebral monoamines, which are catabolized by the cathecol-O-methyltransferase (COMT). The aim of this study is to identify genetic biomarkers of response to VEN that may be used in clinical practice in psychiatry. This work presents two candidate gene studies and a study of panel of genes based on a review of the literature. Methods : Two hundred and six Caucasian patients suffering from a unipolar major depressive episode (DSM-IVTR), requiring a new AD treatment, selected from METADAP cohort, treated by VEN have been studied. The METADAP cohort is a 6-month prospective, multicenter, real-world setting, treatment study in psychiatry. Depression was assessed by the Hamilton scale at the baseline and after 1, 3 and 6 months of AD treatment allowing the evaluation of the percentage of improvement, the response and the remission. Patients were genotyped for the major SNPs (Single Nucleotide Polymorphisms) of CYP2D6 and CYP2C19: loss of function alleles (CYP2D6 *3 rs35742686, *4 rs3892097, *6 rs5030655, the complete gene deletion *5); (CYP2C19 *2 rs4244285, *3 rs4986893, *4 rs28399504, *5 rs56337013); increased function alleles (gene duplication CYP2D6*2xN); (CYP2C19 *17 rs12248560); decreased function alleles (CYP2D6 *10 rs1065852, CYP2D6*41 rs28371725) and COMT Val(108/158)Met, rs4680. The TaqMan allelic discrimination technology was used. Accordingly to the CYP2D6 and CYP2C19 phenotype, the patients were classified in: poor, normal, extensive, intermediate, and ultra-rapid metabolizers and respectively 3 COMT Val(108/158)Met genotypes : Val/Val, Val/Met, Met/Met. Furthermore, 70 patients were sequenced using Next Generation Sequencing (NGS) technologies of MiSeq Illumina for a panel of 70 genes. Results : No association between the evolution of depression of patients treated by VEN and the SNPs of CYP2D6, of CYP2C19 and of COMT was showed in this sample. The NGS data is being analyzed. Le quality of the NGS data has been validated by comparing the results to the TaqMan allelic discrimination of the CYP. Following the review of the literature showing the importance of the OCTs (Organic Cation Transporter) and PMATs (Plasma Membrane Monoamine Transporter) transporters in the transport of monoamines and their role in the AD response, these genes will be integrated in the selection of the panel of genes for the NGS study. Conclusion: This work shows that routine genotyping of the SNPs of CYP2D6, of CYP2C19 and of COMT Val(108/158) Met cannot be recommended in clinical practice in psychiatry for depressed patients treated by VEN. This work will continue with the NGS analyses that will attempt to identify relevant, rare and very rare variants, in particular for genes that have not been studied in a context of MDD such as OCTs and PMATs.
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Submitted on : Tuesday, January 16, 2018 - 5:27:07 PM
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Adela Taranu. Identification de biomarqueurs génétiques de réponse à la venlafaxine dans une cohorte de patients déprimés. Génétique humaine. Université Paris Saclay (COmUE), 2017. Français. ⟨NNT : 2017SACLS356⟩. ⟨tel-01685843⟩

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