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RESUMEN Introducción: El Trastorno depresivo mayor (TDM) es una enfermedad multifactorial en la que, por interacción con diversas variables, se incrementa la vulnerabilidad a padecerla. Diversos modelos han explicado las interacciones, como el de diátesis-estrés. Vivir eventos estresantes no siempre lleva a la aparición del TDM, y se ha planteado que la atribución y la valoración de los eventos estresantes podrían ser un mejor predictor de la aparición de los síntomas. Objetivo: Determinar la asociación y el poder predictivo de la frecuencia y la valoración de eventos vitales estresantes en la presencia de sintomatología del TDM. Métodos: Estudio de casos y controles con 120 pacientes psiquiátricos y 120 personas de la población general. Se utilizó una entrevista clínica estructurada y el Cuestionario de Sucesos Vitales de Sandín y Chorot. Los datos se analizaron con pruebas no paramétricas y regresión logística binaria. Resultados: El grupo de casos obtuvo significativamente más altos en afecto negativo, frecuencia de eventos estresantes, nivel de estrés percibido, valoración negativa de la situación y percepción de no control. El modelo de regresión logística binaria indicó que la baja percepción de control frente al evento estresante es el factor más determinante, seguido por la evaluación negativa del evento. Conclusiones: Las atribuciones realizadas sobre los eventos estresantes son determinantes en la presentación del TDM, en especial la valoración del control percibido frente a los sucesos vitales, en concordancia con los modelos etiológicos del TDM de diátesis cognitiva al estrés. ABSTRACT Introduction: Major depressive disorder (MDD) is a multifactorial disease in which, due to the interaction of several variables, the vulnerability of suffering from it increases. Several models, such as the diathesis-stress model, have explained these interactions. However, experiencing stressful events does not always lead to the development of MDD, and the attribution and appraisal of stressful events contributing to further development of depression symptoms has been considered as a possible explanation. Objective: To determinate the association and the predictive power of the frequency and appraisal of stressful life events to predict MDD symptomatology. Methods: Case-control study with 120 psychiatric patients and 120 people from the general population. A structured clinical interview and the life events questionnaire (Sandín and Chorcot) were used to evaluate the sample. The data were analysed with non-parametric tests and binary logistic regression. Results: The psychiatric patients reported significantly higher levels of negative affect, frequency of stressful life events, perceived stress, negative appraisal of the situation and lack of perceived control. The binary logistic regression model indicated that poor perception of control of the stressful event is the most determining factor, followed by negative evaluation of the situation. Conclusions: The attributions that are made regarding a stressful event are variables that predict MDD, specifically the assessment of the perceived control over the situation. These results concur with the aetiological models of MDD, such as the cognitive diathesis-stress model.

Introduction Major depressive disorder (MDD) is a multifactorial disease in which, due to the interaction of several variables, the vulnerability of suffering from it increases. Several models, such as the diathesis–stress model, have explained these interactions. However, experiencing stressful events does not always lead to the development of MDD, and the attribution and appraisal of stressful events contributing to further development of depression symptoms has been considered as a possible explanation. Objective To determinate the association and the predictive power of the frequency and appraisal of stressful life events to predict MDD symptomatology. Methods Case–control study with 120 psychiatric patients and 120 people from the general population. A structured clinical interview and the life events questionnaire (Sandin and Chorcot) were used to evaluate the sample. The data were analysed with non-parametric tests and binary logistic regression. Results The psychiatric patients reported significantly higher levels of negative affect, frequency of stressful life events, perceived stress, negative appraisal of the situation and lack of perceived control. The binary logistic regression model indicated that poor perception of control of the stressful event is the most determining factor, followed by negative evaluation of the situation. Conclusions The attributions that are made regarding a stressful event are variables that predict MDD, specifically the assessment of the perceived control over the situation. These results concur with the aetiological models of MDD, such as the cognitive diathesis–stress model.

Background Gene × environment (G × E) interactions are known to predict susceptibility to disorders such as depression and anxiety. Adverse experiences in childhood and number of stressful life events (SLEs) have been widely studied as environmental risk factors; however, SLE response has not yet been studied. Here we present a first attempt at the analysis of the interaction between the response to personal and academic stressful events during different life stages and the gene polymorphisms 5-HTTLPR, 5-HTTVNTR (STin2), HTR1A C(− 1019)G, and BDNF Val66Met in the prediction of negative affectivity (NA). Methods Standardized questionnaires (ST-DEP and STAI) were used to measure negative affectivity derived from depression and anxiety in a sample of 303 undergraduate students. Response to stressful events during childhood, high school and college years was evaluated together with a self-report personal history form. Multiple logistic regression analysis was used to perform association and G × E analysis. Results Negative affectivity is strongly associated with childhood maltreatment and stress response. Gene associations were observed between 5-HTTVNTR allele 12 and the S_12 haplotype with NA derived from high scores in both depression and anxiety. The BDNF gene variant was not associated with NA derived from depression or anxiety alone, but it was associated with the comorbid presentation. A significant G × E interaction was observed between the BDNF Val66Met and stress response during childhood and college years although the risk for negative affectivity conferred by stress response during childhood was only significant among the Met allele carriers, while stress response during college years was a significant risk factor regardless of the BDNF Val66Met genotype. A significant G × E interaction was also found between the HTR1A C(− 1019)G variant and childhood maltreatment. Limitations The study has two main limitations, sample size is low and retrospective recognition of SLEs is a concern. Conclusion Altogether, our results demonstrate that the BDNF Val66Met variant moderates the effect of stress during both childhood and college years; although this effect seems to be more critical during childhood given that the risk conferred by childhood stress was restricted to the Met allele carriers. We also found that the HTR1A C(− 1019)G variant moderates the effect of childhood maltreatment in our study population.

Oculocutaneus albinism is a pigment-related inherited disorder characterized by hypopigmentation of the skin, hair and eyes, foveal hypoplasia and low vision. To date, 230 mutations in the TYR gene have been reported as responsible for oculocutaneus albinism type 1 worldwide. TYR gene encodes the enzyme tyrosinase involved in the metabolic pathway of melanin synthesis.Mutations were identified in the TYR gene as responsible for oculocutaneous albinism type 1 in five Colombian individuals, and a new ophthalmic system was tested that corrected visual defects and symptoms in a patient with oculocutaneous albinism.Samples were taken from 5 individuals, four of whom belong to a single family, along with a fifth individual not related to the family. Five exons in the TYR gene were sequenced to search for the gene carriers in the family and in the non-related individual. In addition, clinical ophthalmological evaluation and implementation of an new oculo-visual system was undertaken.A G47D and 1379delTT mutation was identified in the family. The unrelated individual carried a compound heterozygote for the G47D and D42N mutations. The oculo-visual corrective system was able to increase visual acuity and to diminish the nystagmus and photophobia.This is the first study in Colombia where albinism mutations are reported. The methods developed will enable future molecular screening studies in Colombian populations.

Autism spectrum disorders (ASDs) are a range of complex neurodevelopmental conditions principally characterized by dysfunctions linked to mental development. Previous studies have shown that there are more than 1000 genes likely involved in ASD, expressed mainly in brain and highly interconnected among them. We applied whole exome sequencing in Colombian—South American trios. Two missense novel SNVs were found in the same child: ALDH1A3 (RefSeq NM_000693: c.1514T>C (p.I505T)) and FOXN1 (RefSeq NM_003593: c.146C>T (p.S49L)). Gene expression studies reveal that Aldh1a3 and Foxn1 are expressed in ~E13.5 mouse embryonic brain, as well as in adult piriform cortex (PC; ~P30). Conserved Retinoic Acid Response Elements (RAREs) upstream of human ALDH1A3 and FOXN1 and in mouse Aldh1a3 and Foxn1 genes were revealed using bioinformatic approximation. Chromatin immunoprecipitation (ChIP) assay using Retinoid Acid Receptor B (Rarb) as the immunoprecipitation target suggests RA regulation of Aldh1a3 and Foxn1 in mice. Our results frame a possible link of RA regulation in brain to ASD etiology, and a feasible non-additive effect of two apparently unrelated variants in ALDH1A3 and FOXN1 recognizing that every result given by next generation sequencing should be cautiously analyzed, as it might be an incidental finding.