Search

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.

The autism spectrum disorder (ASD) is a complex disorder encompassing a broad phenotypic and genotypic variability. The short (S)/long (L) 5-HTTLPR polymorphism has a functional role in the regulation of extracellular serotonin levels and both alleles have been associated to ASD. Most studies including European, American, and Asian populations have suggested an ethnical heterogeneity of this polymorphism; however, the short/long frequencies from Latin American population have been under-studied in recent meta-analysis. Here, we evaluated the 5-HTTLPR polymorphism in Colombian individuals with idiopathic ASD and reported a non-preferential S or L transmission and a non-association with ASD risk or symptom severity. Moreover, to recognize the allelic frequencies of an under-represented population we also recovered genetic studies from Latin American individuals and compared these frequencies with frequencies from other ethnicities. Results from meta-analysis suggest that short/long frequencies in Latin American are similar to those reported in Caucasian population but different to African and Asian regions.

Introduccion. El albinismo oculo-cutaneo es un trastorno hereditario autosomico recesivo relacionado con la pigmentacion. Sus manifestaciones clinicas incluyen hipopigmentacion en piel, cabello y ojos, hipoplasia en la fovea y disminucion de la agudeza visual. A nivel mundial, hasta el momento, se han reportado, aproximadamente, 230 mutaciones en el gen TYR que causan albinismo oculo-cutaneo de tipo 1. Este gen codifica para la tirosinasa, enzima principal de la biosintesis de melanina. Objetivos. Identificar las mutaciones en el gen TYR responsables del albinismo oculo-cutaneo de tipo 1 en cinco individuos colombianos; cuatro de ellos pertenecen a una misma familia y el otro individuo es un caso aislado no relacionado con la familia. Asimismo, se pretende evaluar un sistema oftalmico que permite corregir problemas de refraccion, y disminuir el nistagmo y la fotofobia en uno de los casos. Materiales y metodos. Se hizo la secuenciacion de los cinco exones del gen TYR en los cinco individuos de estudio y se buscaron portadores en la familia. Se llevo a cabo la evaluacion clinica oftalmologica y la implementacion del sistema correctivo en uno de los pacientes. Resultados. Se encontraron las mutaciones G47D y 1379delTT en la familia, y en el caso aislado, las mutaciones G47D y D42N. Con la implementacion del sistema oculo-visual se logro incrementar la agudeza visual y disminuir el nistagmo.Conclusiones. Por ser el primer estudio en albinismo de este caracter en el pais, estos resultados marcan una pauta para estudios posteriores de tamizacion molecular de albinismo en poblacion colombiana. doi: http://dx.doi.org/10.7705/biomedica.v32i2.638

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.

The ancestry of the Colombian population comprises a large number of well differentiated Native communities belonging to diverse linguistic groups. In the late fifteenth century, a process of admixture was initiated with the arrival of the Europeans, and several years later, Africans also became part of the Colombian population. Therefore, the genepool of the current Colombian population results from the admixture of Native Americans, Europeans and Africans. This admixture occurred differently in each region of the country, producing a clearly stratified population. Considering the importance of population substructure in both clinical and forensic genetics, we sought to investigate and compare patterns of genetic ancestry in Colombia by studying samples from Native and non-Native populations living in its 5 continental regions: the Andes, Caribe, Amazonia, Orinoquía, and Pacific regions. For this purpose, 46 AIM-Indels were genotyped in 761 non-related individuals from current populations. Previously published genotype data from 214 Colombian Natives from five communities were used for population comparisons. Significant differences were observed between Native and non-Native populations, among non-Native populations from different regions and among Native populations from different ethnic groups. The Pacific was the region with the highest African ancestry, Amazonia harboured the highest Native ancestry and the Andean and Orinoquían regions showed the highest proportion of European ancestry. The Andean region was further sub-divided into 6 sub-regions: North East, Central West, Central East, West, South West and South East. Among these regions, the South West region showed a significantly lower European admixture than the other regions. Hardy-Weinberg equilibrium and variance values of ancestry among individuals within populations showed a potential stratification of the Pacific population. COL0035429

Objective: The aim of this study was to determine ancestry informative markers, mitochondrial DNA haplogroups, and the association between HLA-DRB1 alleles and multiple sclerosis (MS) in a group of patients from Bogotá, Colombia. Methods: In this case-control study, genomic DNA was isolated and purified from blood samples. HLA-DRB1 allele genotyping was done using PCR. Mitochondrial hypervariable region 1 was amplified and haplogroups were determined using HaploGrep software. Genomic ancestry was estimated by genotyping a panel of ancestry informative markers. To test the association of HLA polymorphisms and MS, we ran separate multivariate logistic regression models. Bonferroni correction was used to account for multiple regression tests. Results: A total of 100 patients with MS (mean age 40.4 ± 12 years; 70% females) and 200 healthy controls (mean age 37.6 ± 11 years; 83.5% females) were included in the analysis. Ancestry proportions and haplogroup frequencies did not differ between patients and controls. HLA-DRB1*15 was present in 31% of cases and 13.5% of controls, whereas HLA-DRB1*14 was present in 5% of cases and 15.5% of controls. In the multivariate model, HLA-DRB1*15 was significantly associated with MS (odds ratio [OR] = 3.05, p < 0.001), whereas HLA-DRB1*14 was confirmed as a protective factor in our population (OR = 0.16, p = 0.001). Conclusions: This study provides evidence indicating that HLA-DRB1*15 allele confers susceptibility to MS and HLA-DRB1*14 allele exerts resistance to MS in a highly admixed population. This latter finding could partially explain the low prevalence of MS in Bogotá, Colombia.

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.

Major depressive disorder (MDD) is a multifactorial disorder known to be influenced by both genetic and environmental factors. MDD presents a heritability of 37%, and a genetic contribution has also been observed in studies of family members of individuals with MDD that imply that the probability of suffering the disorder is approximately three times higher if a first-degree family member is affected. Childhood maltreatment and stressful life events (SLEs) have been established as critical environmental factors that profoundly influence the onset of MDD. The serotonin pathway has been a strong candidate for genetic studies, but it only explains a small proportion of the heritability of the disorder, which implies the involvement of other pathways. The serotonin (5-HT) pathway interacts with the stress response pathway in a manner mediated by the hypothalamic-pituitary-adrenal (HPA) axis. To analyze the interaction between the pathways, we propose the use of a synchronous Boolean network (SBN) approximation. The principal aim of this work was to model the interaction between these pathways, taking into consideration the presence of selective serotonin reuptake inhibitors (SSRIs), in order to observe how the pathways interact and to examine if the system is stable. Additionally, we wanted to study which genes or metabolites have the greatest impact on model stability when knocked out in silico. We observed that the biological model generated predicts steady states (attractors) for each of the different runs performed, thereby proving that the system is stable. These attractors changed in shape, especially when anti-depressive drugs were also included in the simulation. This work also predicted that the genes with the greatest impact on model stability were those involved in the neurotrophin pathway, such as CREB, BDNF (which has been associated with major depressive disorder in a variety of studies) and TRkB, followed by genes and metabolites related to 5-HT synthesis.