RESUMO
Los portadores de anomalías estructurales cromosómicas equilibradas, a pesar de ser fe-notípicamente normales, tienen una competencia reproductiva disminuida de manera significativa conrespecto a la población general. Esto se debe a que, durante la gametogénesis, dependiendo de cómo sesegregue la alteración cromosómica en la meiosis I, se generarán gametos normales, equilibrados o des-equilibrados en mayor proporción que en portadores de cariotipos normales. Esta es la causa principalEstudio del efecto intercromosómico en portadores de anomalías cromosómicasestructurales equilibradas mediante PGT-SRStudy of the interchromosomal effect in carriers of balanced structuralchromosomal rearrangements by PGT-SR de la mayor tasa de abortos y descendencia con alteraciones que presentan los individuos portadores de inversiones ytranslocaciones recíprocas o robertsonianas. Otra posible fuente de gametos y/o embriones aneuploides, es el denominadoefecto intercromosómico (EIC), que consiste en una interferencia producida por una alteración cromosómica estructuralsobre la adecuada disyunción y segregación de otros cromosomas no involucrados en dicha alteración.Material y Métodos:Un total de 40 parejas fueron incluidas en el estudio, de las cuales 31 pertenecieron al grupo de es-tudio: catorce translocaciones robertsonianas, trece translocaciones recíprocas y cuatro de inversiones pericéntricas. Endiecinueve casos la mujer era portadora y en los doce restantes era el hombre el afecto. Nueve parejas con cariotipo normal,portadoras de una mutación responsable de enfermedad monogénica fueron incluidas en el grupo control. (AU)
Introduction: Carriers of balanced structural rearrangements, despite being phenotypically normal, they have a signifi-cantly decreased reproductive competence compared to the general population. The reason is because, during gametoge-nesis, depending on how the chromosomal alteration is segregated in meiosis I, normal, balanced, or unbalanced gameteswill be generated in greater proportion than in carriers of normal karyotypes. This is the main cause of the higher rate ofabortions and offspring with alterations that carriers of inversions, reciprocal translocations or Robertsonian translocationspresent. Another possible source of aneuploid gametes and/or embryos is the so-called interchromosomal effect (ICE),which consists of an interference produced by a structural chromosomal alteration on the proper disjunction and segregationof other chromosomes not involved in the rearrangement.Material and methods:A total of 40 couples were included in the study, of which 31 belonged to the study group: fourteenRobertsonian translocations, thirteen reciprocal translocations and four pericentric inversions. As for the affected parent,in nineteen of the cases the woman was the carrier of the chromosomal alteration and in the remaining twelve it was theman who was affected. Nine couples with a normal karyotype, carriers of a mutation responsible for monogenic disease,were included in the control group. (AU)
Assuntos
Humanos , Fertilização In Vitro , Cromossomos , Células Germinativas , DiagnósticoRESUMO
La distrofia miotónica tipo 1 (DM1) es la forma más común de distrofia muscular en adultos causada por la expansión de una repetición de trinucleótidos CTG en el gen DMPK (Distrofia miotónica proteína quinasa) y su herencia es autosómica dominante. Hasta el momento, la técnica de Diagnóstico Genético Preimplantacional parece ser la aproximación reproductiva más eficaz para aquellas parejas en las que alguno de sus progenitores es afecto de DM1. En este estudio se evaluó la técnica de Diagnóstico Genético Preimplantacional en función del sexo del progenitor afecto y el número de repeticiones CTG y su influencia sobre el resultado reproductivo de la misma. Un total de 13 parejas, del programa de Diagnóstico Genético Preimplantacional de la Unidad de Reproducción Asistida del Hospital Universitari i Politècnic La Fe, fueron incluidas en el estudio. En 8 de éstas la afecta es la mujer, mientras que en las 5 restantes es el hombre el portador de la enfermedad. En todas ellas se llevaron a cabo todos los pasos del programa. Los embriones fueron analizados mediante mTP-PCR y PCR multiplex. El efecto de ambas variables se analizó mediante análisis bivariado (prueba T, Chi-cuadrado, regresión lineal y test Anova) y análisis multivariante utilizando análisis de correlación (Rho de Spearman). Los resultados obtenidos revelaron una transmisión preferencial de los alelos expandidos en DM1, independiente del sexo del progenitor afecto. A pesar de ello, no mostraron ninguna relación estadísticamente significativa entre el sexo del progenitor afecto ni el número de repeticiones CTG y el resultado reproductivo de la técnica. De modo que, atendiendo a nuestros resultados, el Diagnóstico Genético Preimplantacional sería una buena aproximación reproductiva en casos de DM1 con una tasa de gestación de 53,8 % y de nacidos sanos de 38,5 %, independientemente del sexo del progenitor afecto y del número de repeticiones CTG
Myotonic dystrophy type 1 (DM1) is the most common form of muscular dystrophy in adults caused by the expansion of a CTG trinucleotide repeat in the DMPK gene (dystrophia myotonica-protein kinase gene) and its inheritance is autosomal dominant. So far, the technique of Preimplantation Genetic Diagnosis (PGD) seems to be the most effective reproductive approach for those couples in which one of their parents is affected by DM1. In this study, the Preimplantation Genetic Diagnosis technique was evaluated according to the sex of the affected progenitor and the number of CTG repetitions and their influence on the reproductive result of itself. A total of 13 couples from the Preimplantation Genetic Diagnosis program of the Assisted Reproduction Unit of the Hospital Universitario i Politècnic La Fe were included in the study were included in the study. In 8 of them the affected parent is the woman, whereas the 5 remaining is the man who is the disease carrier. In all of them, all the steps of the program were followed. The embryos were analyzed by mTP-PCR and multiplex PCR. The variables effect was analyzed by bivariate analysis (T-test, Chi-square, linear regression and Anova test) and multivariate analysis using correlation analysis (Spearman's rho). The results obtained revealed a preferential transmission of the expanded alleles in DM1, regardless of the sex of the affected parent. In spite of, the results obtained do not show any statistically significant relation between the sex of the progenitor and the number of repetitions and the reproductive result of the technique. Thus, according to our results, Preimplantation Genetic Diagnosis would be a good reproductive approach in cases of DM1 with a gestation rate of 53.8% and healthy births of 38.5%, regardless of the sex of the affected parent and the number of CTG repetitions
Assuntos
Humanos , Masculino , Feminino , Gravidez , Recém-Nascido , Adulto , Distrofia Miotônica/diagnóstico , Distrofia Miotônica/genética , Diagnóstico Pré-Implantação , Estudos Transversais , Estudos Retrospectivos , Reação em Cadeia da Polimerase , Haplótipos/genética , Injeções de Esperma Intracitoplásmicas , CriopreservaçãoRESUMO
The risk of multiple pregnancy to maternal-fetal health can be minimized by reducing the number of embryos transferred. New tools for selecting embryos with the highest implantation potential should be developed. The aim of this study was to evaluate the ability of morphological and morphometric variables to predict implantation by analysing images of embryos. This was a retrospective study of 135 embryo photographs from 112 IVF-ICSI cycles carried out between January and March 2011. The embryos were photographed immediately before transfer using Cronus 3 software. Their images were analysed using the public program ImageJ. Significant effects (P < 0.05), and higher discriminant power to predict implantation were observed for the morphometric embryo variables compared with morphological ones. The features for successfully implanted embryos were as follows: four cells on day 2 of development; all blastomeres with circular shape (roundness factor greater than 0.9), an average zona pellucida thickness of 13 µm and an average of 17695.1 µm² for the embryo area. Embryo size, which is described by its area and the average roundness factor for each cell, provides two objective variables to consider when predicting implantation. This approach should be further investigated for its potential ability to improve embryo scoring.
