Effect of master mixes on the measurement of telomere length by qPCR.

Alterations in telomere length (TL) have been associated with several diseases and a method based on qPCR, the Monochrome Multiplex Real-Time Quantitative PCR (MMQPCR) technique, has been used extensively for the analysis of TL. Some previous studies have been found that certain methodological conditions can affect the measurement of TL. The aim of the study was to evaluate the performance of eight different commercially available SYBR Green and High-Resolution Melting (HRM) mixes on the measurement of TL by the MMQPCR method. Four SYBR Green and four HRM mixes were tested and the measurement of TL was expressed by the T/S ratio. It was found that the type of master mix used in MMQPCR influences the measurement of TL, affecting aspects such as the specificity and consistency of the results. Our results are the first description of the effects of different master mixes on TL analysis by MMQPCR and highlight the importance of the future methodological improvement of this broadly used technique.

APOE gene and neuropsychiatric disorders and endophenotypes: A comprehensive review.

The Apolipoprotein E (APOE) gene is one of the main candidates in neuropsychiatric genetics, with hundreds of studies carried out in order to explore the possible role of polymorphisms in the APOE gene in a large number of neurological diseases, psychiatric disorders, and related endophenotypes. In the current article, we provide a comprehensive review of the structural and functional aspects of the APOE gene and its relationship with brain disorders. Evidence from genome-wide association studies and meta-analyses shows that the APOE gene has been significantly associated with several neurodegenerative disorders. Cellular and animal models show growing evidence of the key role of APOE in mechanisms of brain plasticity and behavior. Future analyses of the APOE gene might find a possible role in other neurological diseases and psychiatric disorders and related endophenotypes. © 2016 Wiley Periodicals, Inc.

Telomere length and childhood trauma in Colombians with depressive symptoms.

OBJECTIVE: Childhood trauma and telomere length (TL) are important risk factors for major depressive disorder. We examined whether there was an association between childhood trauma and TL in a sample of Colombians who were assessed for depressive symptoms. METHODS: We applied the Center for Epidemiologic Studies Depression scale, the Patient Health Questionnaire-9, the Hospital Anxiety and Depression scale and the Childhood Trauma Questionnaire to 92 Colombian subjects (mean age = 21). TL was measured with quantitative PCR. Spearman's correlation coefficient (rs) was used to analyze the relationship between childhood trauma scores and TL. RESULTS: We found a significant correlation between TL and sexual abuse scores (rs = 0.428, p = 0.002) in individuals with higher depressive symptom scores. CONCLUSION: This is the first report of a significant association between TL and sexual abuse in a Latin American sample and provides additional evidence about the role of childhood trauma and TL in neuropsychiatric disorders.

A Functional Polymorphism in the DRD1 Gene, That Modulates Its Regulation by miR-504, Is Associated with Depressive Symptoms.

OBJECTIVE: The aim of this study was to examine a possible association between depressive symptoms and a functional polymorphism (rs686) that modulates the regulation of DRD1 gene by miR-504. METHODS: A total of 239 young Colombian subjects were evaluated with the Patient Health Questionnaire-9 (PHQ-9) scale and genotyped for the rs686 polymorphism. A linear regression model, corrected by age and gender, was used. RESULTS: A significant association between the rs686 polymorphism and PHQ-9 scores was found, under a dominant genetic model (p=0.0094). CONCLUSION: These results provide novel evidence about the growing role of inherited variants in binding sites for brain-expressed miRNAs on depressive symptomatology.

MTHFR gene methylation is associated with perceived stress in healthy young adults.

BACKGROUND: Epigenetic factors have been identified in the past years as interesting candidates for psychiatric disorders and related endophenotypes. It has been found that the methylenetetrahydrofolate reductase (MTHFR) gene is associated with major depressive disorder, and the aim of the current study was to examine the possible association between perceived stress and MTHFR methylation, taking into account depressive symptoms as a covariate. PARTICIPANTS AND METHODS: Seventy-eight healthy Colombian participants (mean age=20.9 years; SD=3.0) were evaluated with the Perceived Stress Scale and with the Patient Health Questionnaire-9 for depressive symptomatology. MTHFR methylation levels were measured with a methylation-sensitive high-resolution melting method. A multiple regression analysis (adjusting for age, sex, and depressive symptoms) was carried out to assess the association between MTHFR methylation and perceived stress scores. RESULTS: We found a significant inverse correlation between MTHFR methylation levels and perceived stress scores (r=-0.502; P=5.9×10(-5)), which remained significant after being adjusted for age, sex, and depressive symptomatology. CONCLUSION: To our knowledge, this is the first study that reports an association between perceived stress and MTHFR methylation levels. This report adds evidence to the emerging role of epigenetic changes in endophenotypes related to affective disorders.

Depressive symptoms are associated with a functional polymorphism in a miR-433 binding site in the FGF20 gene.

Genetic studies of major depressive disorder and its associated endophenotypes are useful for the identification of candidate genes. In recent years, variations in non-coding RNA genes, such as miRNAs, have been explored as novel candidates for psychiatric disorders and related endophenotypes. The aim of the present study was to evaluate the possible association between a functional polymorphism (rs12720208) in the FGF20 gene, which regulates its modulation by miR-433, and depressive symptoms in young adults. A sample of 270 participants from Colombia were evaluated with the Hospital Anxiety and Depression Scale - Depression Subscale (HADS-D) and genotyped for the rs12720208 polymorphism using a TaqMan assay. A lineal regression analysis was used. A statistically significant association of the functional polymorphism in the FGF20 gene (rs12720208) with depressive symptoms was found. It was observed that individuals with the G/A genotype had higher scores for the HADS-D subscale. Our results are the first description in the scientific literature about a significant association between a functional polymorphism in the FGF20 gene, which regulates its modulation by miR-433, and depressive symptoms.

Higher scores in the extraversion personality trait are associated with a functional polymorphism in the PER3 gene in healthy subjects.

A polymorphism in the PER3 (period circadian clock 3) gene has been associated with neuropsychiatric disorders and endophenotypes. We evaluated the possible association of personality domains with the PER3 polymorphism in a sample of healthy subjects: 271 individuals were evaluated with the Big Five Inventory and genotyped for the PER3 Variable Number Tandem Repeat (VNTR) polymorphism. We found a significant association between the PER3 polymorphism and the extraversion personality trait (p = 0.0093). The 5/5 genotype carriers showed higher scores for extraversion. This is the first time that a significant association between the PER3 VNTR polymorphism and extraversion is reported.

Val158Met polymorphism in the COMT gene is associated with hypersomnia and mental health-related quality of life in a Colombian sample.

The identification of genes that are risk factors for major depressive disorder remains a main task for global psychiatric research. The Catechol-O-methyltransferase (COMT) gene has been an important candidate risk factor for several psychiatric disorders. Previous studies have shown that a functional polymorphism (Val158Met) in this gene has an effect on several brain circuits and endophenotypes of psychiatric relevance. The aim of this study was to explore the association of a functional polymorphism in the COMT gene with psychological distress, sleep problems and health-related quality of life. Two hundred seventy young Colombian subjects (mean age: 21.3 years; range: 18-57 years) completed the Patient Health Questionnaire-9, the Perceived Stress Scale, the Oviedo Sleep Questionnaire and the 12-Item Short-Form Health Survey and were genotyped for the Val158Met polymorphism (rs4680) in the COMT gene. A linear regression analysis, adjusting for potential confounding factors, was carried out. Subjects that were Met carriers (Val/Met and Met/Met genotypes) showed higher scores for hypersomnia (p=0.001) and lower scores for mental health-related quality of life (p=0.007), these associations remained significant after correcting for multiple testing. These findings support the hypothesis of a broad effect of the Val158Met polymorphism in the COMT gene on several dimensions of behavior and neuropsychiatric symptoms.

Telomere length and childhood trauma in Colombians with depressive symptoms

Objective: Childhood trauma and telomere length (TL) are important risk factors for major depressive disorder. We examined whether there was an association between childhood trauma and TL in a sample of Colombians who were assessed for depressive symptoms. Methods: We applied the Center for Epidemiologic Studies Depression scale, the Patient Health Questionnaire-9, the Hospital Anxiety and Depression scale and the Childhood Trauma Questionnaire to 92 Colombian subjects (mean age = 21). TL was measured with quantitative PCR. Spearman's correlation coefficient (rs) was used to analyze the relationship between childhood trauma scores and TL. Results: We found a significant correlation between TL and sexual abuse scores (rs = 0.428, p = 0.002) in individuals with higher depressive symptom scores. Conclusion: This is the first report of a significant association between TL and sexual abuse in a Latin American sample and provides additional evidence about the role of childhood trauma and TL in neuropsychiatric disorders.