Hallazgos citogenéticos y edad materna en pacientes con síndrome down en un hospital de referencia pediátrico en el Perú

Introducción: El síndrome Down es un trastorno congénito originado por una trisomía total o parcial del cromosoma 21 y es considerada la causa genética más común de malformaciones congénitas y discapacidad intelectual. El objetivo de este estudio fue describir las alteraciones citogenéticas de pacientes con Síndrome Down y su relación con la edad materna. Métodos: Estudio transversal, descriptivo-analítico. Se incluyó 436 pacientes con Síndrome Down admitidos en el Instituto Nacional de Salud del Niño durante el período 2017-2019. Se analizaron las variables: alteración citogenética y edad materna. Resultados: Se encontró que el 99,3% (n=433) de pacientes presentaron algún tipo de alteración citogenética y tres pacientes presentaron cariotipo normal. La edad de los pacientes al momento de la toma de muestra estuvo comprendida entre los 0,03 y 17 años, la relación masculino/femenino fue de 1.2:1. La alteración citogenética más frecuente fue la trisomía 21 libre (94,7%), seguida por la translocación Robertsoniana (n=16) y el mosaicismo (n=6). En el caso de la edad materna se encontró una mediana de 37 años (rango: 13-47). Conclusiones: La trisomía 21 libre es la alteración citogenética más común en Síndrome Down; sin embargo, la translocación Robertsoniana y los mosaicismos fueron más frecuentes en edad materna menor de 35 años, sugiriendo que existe otros factores de riesgo diferentes a la edad materna avanzada en este grupo etario.

Introduction: Down syndrome is a congenital disorder caused by a total or partial trisomy of chromosome 21 and is considered the most common genetic cause of congenital malformations and intellectual disability. The objective of this study was to describe the cytogenetic alterations of patients with Down syndrome and their relationship with maternal age. Methods: Cross-sectional, descriptive-analytical study. 436 patients with Down syndrome admitted to the Instituto Nacional de Salud del Niño during the 2017-2019 period were included. The variables analyzed were: cytogenetic diagnosis and maternal age. Results: It was found that 99,3% (n=433) of patients presented some type of cytogenetic alteration and three patients presented a normal karyotype. The age of the patients at the time of sampling was between 0,03 and 17 years, the male/female ratio was 1.2:1. The most frequent cytogenetic alteration was free trisomy 21 (94,7%), followed by Robertsonian translocation (n=16) and mosaicism (n=6). In the case of maternal age, a median of 37 years was found (range: 13-47). Conclusions: Free trisomy 21 is the most common cytogenetic condition in Down syndrome; however, the Robertsonian translocation and mosaicisms were more frequent in patients whose mothers were les than 35 years old, suggesting that there are other risk factors than advanced maternal age in this group.

Mitofusin 2 in Macrophages Links Mitochondrial ROS Production, Cytokine Release, Phagocytosis, Autophagy, and Bactericidal Activity.

Mitofusin 2 (Mfn2) plays a major role in mitochondrial fusion and in the maintenance of mitochondria-endoplasmic reticulum contact sites. Given that macrophages play a major role in inflammation, we studied the contribution of Mfn2 to the activity of these cells. Pro-inflammatory stimuli such as lipopolysaccharide (LPS) induced Mfn2 expression. The use of the Mfn2 and Mfn1 myeloid-conditional knockout (KO) mouse models reveals that Mfn2 but not Mfn1 is required for the adaptation of mitochondrial respiration to stress conditions and for the production of reactive oxygen species (ROS) upon pro-inflammatory activation. Mfn2 deficiency specifically impairs the production of pro-inflammatory cytokines and nitric oxide. In addition, the lack of Mfn2 but not Mfn1 is associated with dysfunctional autophagy, apoptosis, phagocytosis, and antigen processing. Mfn2floxed;CreLysM mice fail to be protected from Listeria, Mycobacterium tuberculosis, or LPS endotoxemia. These results reveal an unexpected contribution of Mfn2 to ROS production and inflammation in macrophages.

Circadian- and UPR-dependent control of CPEB4 mediates a translational response to counteract hepatic steatosis under ER stress.

The cytoplasmic polyadenylation element-binding (CPEB) proteins regulate pre-mRNA processing and translation of CPE-containing mRNAs in early embryonic development and synaptic activity. However, specific functions in adult organisms are poorly understood. Here we show that CPEB4 is required for adaptation to high-fat-diet- and ageing-induced endoplasmic reticulum (ER) stress, and subsequent hepatosteatosis. Stress-activated liver CPEB4 expression is dual-mode regulated. First, Cpeb4 mRNA transcription is controlled by the circadian clock, and then its translation is regulated by the unfolded protein response (UPR) through upstream open reading frames within the 5'UTR. Thus, the CPEB4 protein is synthesized only following ER stress but the induction amplitude is circadian. In turn, CPEB4 activates a second wave of UPR translation required to maintain ER and mitochondrial homeostasis. Our results suggest that combined transcriptional and translational Cpeb4 regulation generates a 'circadian mediator', which coordinates hepatic UPR activity with periods of high ER-protein-folding demand. Accordingly, CPEB4 deficiency results in non-alcoholic fatty liver disease.

Carbohydrate-based experimental therapeutics for cancer, HIV/AIDS and other diseases.

This review, primarily for general readers, briefly presents experimental approaches to therapeutics of cancer, HIV/AIDS and various other diseases based on advances in glycobiology and glycochemistry. Experimental cancer and HIV/AIDS vaccines are being developed in attempts to overcome weak immunological responses to carbohydrate-rich surface antigens using carriers, adjuvants and novel carbohydrate antigen constructs. Current carbohydrate-based vaccines are used for typhus, pneumonia, meningitis; vaccines for anthrax, malaria and leishmaniasis are under development. The link between O-linked beta-N-acetylglucosamine glycosylation and protein phosphorylation in diseases including diabetes and Alzheimer's disease is also explored. Carbohydrate-associated drugs that are in current use or under development, such as heparan sulfate binders, lectins, acarbose, aminoglycosides, tamiflu and heparin, and technologies using carbohydrate and lectin microarrays that offer improved diagnostic and drug development possibilities, are described. Advances in carbohydrate synthesis, analysis and manipulation through the emerging fields of glycochemistry and glycobiology are providing new approaches to disease therapeutics.

Microbead analysis of cell binding to immobilized lectin: an alternative to microarrays in the development of carbohydrate drugs and diagnostic tests.

Microarray technology is currently used in the development of carbohydrate drugs and diagnostic tests. Here we model an inexpensive alternative to microarrays using derivatized microbeads. In this model we examine the binding of mannose-rich yeast to microbeads derivatized with concanavalin A (Con A), a mannose-binding lectin, in the presence of 30 different sugars and 9 different pH conditions. We developed a listing of effective saccharide inhibitors of immobilized Con A based on 3901 replicates. We suggest that this is the most extensive saccharide inhibitor list ever developed for this lectin and it may be useful to use this listing to replace the less extensive lists that have been in the literature for decades. Information is also provided on pH effects on immobilized Con A binding based on 918 trials. Two assays to study binding, one which qualitatively scores more or less binding than control in thousands of replicate samples, and another that quantitatively evaluates binding by counting the number of cells bound to each bead, are also modeled here. We know of no previous studies that provide such extensive information on saccharide inhibition and pH effects on the binding of immobilized Con A. We suggest that this microbead approach, using beads derivatized with lectins or sugars, and the two simple assays presented here, can in some cases substitute for more expensive microarray technology in the development of carbohydrate drugs and diagnostic tests. If, for example, our model Saccharomyces cerevisiae was a pathogen, these studies show that it binds via cell surface mannose residues and drugs to prevent binding could be developed using the inhibitors of binding identified here. The beads could be also used in the development of diagnostic tests that identify the presence of the organism in blood samples, etc. in much the same way as microarray technology is being used today.