El diagnóstico genético preimplantacional y sus nuevas indicaciones en reproducción asistida

Clinical application of embryo aneuploidy testing by next-generation sequencing

Abstract We review here the evolution in the field of embryo aneuploidy testing over the last 20 years, from the analysis of a subset of chromosomes by fluorescence in situ hybridisation to the transition toward a more comprehensive analysis of all 24 chromosomes. This current comprehensive aneuploidy testing most commonly employs next-generation sequencing (NGS). We present our experience in over 130 000 embryo biopsies using this technology. The incidence of aneuploidy was lower in trophectoderm biopsies compared to cleavage-stage biopsies. We also confirmed by NGS that embryo aneuploidy rates increased with increasing maternal age, mostly attributable to an increase in complex aneuploid …

Smoking habits of parents and male: female ratio in spermatozoa and preimplantation embryos

BACKGROUND Previous observations have addressed a decreased male:female ratio associated with smoking. Our aim was to assess whether this effect is observed at the spermatozoa or at the early embryo development. METHODS We retrospectively assessed smoking intake habits of 56 couples included in our preimplantation genetic diagnosis (PGD) program. Three groups were established according to male or female cigarette consumption per day: non-smokers, smokers (1-19 cigarettes per day) and heavy smokers (> or =20 cigarettes per day). Fluorescence in-situ hybridization (FISH) was performed on ejaculated sperm samples to analyse chromosomes X and Y. On day 3, embryos were also analysed. Additionall…

How many single embryo transfers would be needed to perform an euploid embryo transfer according to the age of the patient?

Cigarette Consumption and X-Sperm Enrichment After Swim-Up

Embryo Aneuploidy Screening for Unexplained Recurrent Miscarriage: A Minireview

Problem:  The aim of this study was to investigate the incidence of chromosomal abnormalities in unexplained recurrent miscarriage (RM) patients and assess the role of pre-implantation genetic diagnosis (PGD) in preventing subsequent pregnancy loss and improving pregnancy outcome. Method of Study:  Pre-implantation genetic diagnosis was performed in 241 RM cycles and in 35 cycles in patients undergoing PGD for sex-linked diseases (control group). Chromosomes 13, 16, 18, 21, 22, X and Y were analysed by fluorescence in situ hybridization. Results:  The implantation and pregnancy rates in RM patients were 26.4 and 36.5% versus 20.6 and 29.0% in the control group, respectively. The percentage …

Analysis of chromosomal abnormalities in testicular and epididymal spermatozoa from azoospermic ICSI patients by fluorescence in-situ hybridization

BACKGROUND: An increased incidence of numerical chromosomal abnormalities has been reported in the ejaculated spermatozoa of infertile patients. However, there are few cytogenetic studies of testicular and epididymal spermatozoa, and their results are still controversial. METHODS: Fluorescence in-situ hybridization (FISH) analysis of chromosomes 13, 18, 21, X and Y was performed on seven testicular samples and two epididymal samples from patients with obstructive azoospermia (OA), and on 13 testicular samples from patients with non-obstructive azoospermia (NOA). Five ejaculated sperm samples from normozoospermic fertile donors were evaluated as a control group. RESULTS: Both epididymal sper…

Preimplantation genetic diagnosis by fluorescence in situ hybridization: clinical possibilities and pitfalls.

Preimplantation genetic diagnosis using the fluorescence in situ hybridization technique (FISH) is being used widely to prevent the transmission of sex-linked diseases, to screen for translocations, and for aneuploidy screenng in specific invitro fertilization (IVF) patient groups, along with FISH analysis of spematozoa in intertile men. In this study, we aim to critically analyze our clinical results in patients at risk of transmitting sex-linked diseases (n = 55), in carriers of translocations (n = 43), in women who have recurent miscarriage (two or more miscarriages) (n = 128), recurrent IVF failure (three or more failed IVF attempts) (n = 47), and patients of advanced maternal age (37 y…

FISH screening of aneuploidies in preimplantation embryos to improve IVF outcome

Preimplantation genetic diagnosis (PGD) has transformed the approach to the infertility patient in the IVF setting. Although the principal applications of PGD have been to prevent the transmission of sex-linked diseases, in time and with growing knowledge of the chromosomal abnormalities observed in preimplantation embryos, its applications have widened. Nowadays, apart from its implications in the prevention of transmission of chromosomal and genetic abnormalities, PGD is being used with increased frequency to improve the IVF outcome in patients with advanced maternal age (or =38 years of age), recurrent miscarriage (or =2 miscarriages), recurrent IVF failure (or =3 failed IVF attempts) an…

False positive rate of an arrayCGH platform for single-cell preimplantation genetic screening and subsequent clinical application on day-3

In this work, false positive rate of an arrayCGH platform for its use in day-3 single-blastomere analysis was calculated. For this purpose, 38 embryos diagnosed as abnormal on day-3 by FISH were re-biopsied on day-4. Single-cell day-4 arrayCGH diagnosis was then performed. A successful amplification was obtained in 97.4 % (37/38) of the day-4 cells analysed by arrayCGH. Day-3 FISH and day-4 arrayCGH diagnosis were concordant in 35/37 cases. The two discordant embryos were spread and all the cells from each embryo were re-analysed by FISH on day 5. The same error rate (2.7 %) for day-3 FISH and day-4 arrayCGH was obtained when comparing day-5 FISH re-analysis. After this pre-clinical phase, …

Impact of chromosomal abnormalities on preimplantation embryo development.

Objectives To evaluate the influence of numerical chromosomal abnormalities on preimplantation embryo development. Methods This study includes 6936 embryos from 1245 women undergoing preimplantation genetic diagnosis (PGD). Indications for aneuploidy screening were: recurrent miscarriages, implantation failure, severe male factor, advanced maternal age, and mixed causes. Embryo biopsy was performed on day 3, and embryos were co-cultured until day 5, when embryo transfer was performed. Results In the aneuploidy screening regimen, normal euploid embryos showed significantly higher blastocyst rates (68.2%) compared to chromosomally abnormal (42.8%, p < 0.0001) and mosaic (53.7%, p < 0.0001) em…

New Tools for Embryo Selection: Comprehensive Chromosome Screening by Array Comparative Genomic Hybridization

The objective of this study was to evaluate the usefulness of comprehensive chromosome screening (CCS) using array comparative genomic hybridization (aCGH). The study included 1420 CCS cycles for recurrent miscarriage (n=203); repetitive implantation failure (n=188); severe male factor (n=116); previous trisomic pregnancy (n=33); and advanced maternal age (n=880). CCS was performed in cycles with fresh oocytes and embryos (n=774); mixed cycles with fresh and vitrified oocytes (n=320); mixed cycles with fresh and vitrified day-2 embryos (n=235); and mixed cycles with fresh and vitrified day-3 embryos (n=91). Day-3 embryo biopsy was performed and analyzed by aCGH followed by day-5 embryo tran…

Chromosomal abnormalities and clinical outcome in patients with advanced maternal age (AMA) using comprehensive chromosome screening (CCS)

High incidence of chromosomal abnormalities in large-headed and multiple-tailed spermatozoa

Rodrigo Vivo, Lorena, lorovi@alumni.uv.es ; Prados Dodd, Nicolas, Nicolas.Prados@uv.es ; Gil Salom, Manuel Luis, Manuel.Gil-Salom@uv.es ; Remohi Gimenez, Jose Alejandro, J.Alejandro.Remohi@uv.es

Genetic Analysis of Human Preimplantation Embryos

Preimplantation development comprises the initial stages of mammalian development, before the embryo implants into the mother's uterus. In normal conditions, after fertilization the embryo grows until reaching blastocyst stage. The blastocyst grows as the cells divide and the cavity expands, until it arrives at the uterus, where it "hatches" from the zona pellucida to implant into the uterine wall. Nevertheless, embryo quality and viability can be affected by chromosomal abnormalities, most of which occur during gametogenesis and early embryo development; human embryos produced in vitro are especially vulnerable. Therefore, the selection of chromosomally normal embryos for transfer in assis…

Sperm chromosomal abnormalities and their contribution to human embryo aneuploidy.

In this work we reviewed 18 years of experience using fluorescence in situ hybridization (FISH) for sperm aneuploidy testing. We evaluated parameters associated with increased numerical sperm chromosome abnormalities and determined the male contribution to embryo aneploidies in terms of reproductive outcome by increased sperm aneuploidy. This retrospective study analyzed data from 2008 sperm samples of infertile males undergoing FISH analysis because of clinical history of repetitive implantation failure, recurrent miscarriage, impaired sperm parameters, or mixed causes. Sperm concentration was the only sperm parameter associated with FISH results—we observed a gradual increase of abnormal …

Moderate ovarian stimulation does not increase the incidence of human embryo chromosomal abnormalities in in vitro fertilization cycles.

A high chromosomal abnormalities rate has been observed in human embryos derived from in vitro fertilization (IVF) treatments. The real incidence in natural cycles has been poorly studied, so whether this frequency may be induced by external factors, such as use of gonadotropins for ovarian stimulation, remains unknown.We conducted a prospective cohort study in a University-affiliated private infertility clinic with a comparison between unstimulated and stimulated ovarian cycles in the same women. Preimplantation genetic screening by fluorescence in situ hybridization was performed in all viable d 3 embryos.The primary objective was to compare the incidence of embryo chromosomal abnormaliti…

Type of chromosome abnormality affects embryo morphology dynamics.

Objective To study the differences in the cleavage time between types of embryo chromosomal abnormalities and elaborate algorithm to exclude aneuploid embryos according to the likelihood to be euploid. Design Retrospective cohort study. Setting University affiliated private center. Patient(s) Preimplantational genetic screening patients (n = 112) including cases of advanced maternal age, repeated implantation failure, and recurrent miscarriage. A total of 485 embryos were analyzed. Intervention(s) None. Main Outcome Measure(s) All biopsied embryos were cultured in an incubator with time-lapse technology, cleavage timing from insemination to day 3 and all kinetic parameters that have been de…

Testicular sperm from patients with obstructive and nonobstructive azoospermia: aneuploidy risk and reproductive prognosis using testicular sperm from fertile donors as control samples.

Objective To establish a baseline incidence of chromosomal abnormalities in testicular sperm of fertile men and to determine the best control sample for comparisons with azoospermic males to estimate their reproductive prognosis. Design Prospective study. Setting Infertility clinic. Patient(s) Sixteen obstructive azoospermic (OA) and 19 nonobstructive azoospermic patients (NOA). Control samples were ejaculated sperm from ten fertile donors and testicular sperm from ten other fertile donors. Intervention(s) Fluorescence in situ hybridization (FISH) in sperm. Main Outcome Measure(s) Sperm numerical abnormalities for chromosomes 13, 18, 21, X, and Y; ongoing implantation and pregnancy rates in…

Increasing the probability of selecting chromosomally normal embryos by time-lapse morphokinetics analysis

Objective To study the differences in the cleavage time between chromosomally normal and abnormal embryos and to elaborate an algorithm to increase the probability of noninvasively selecting chromosomally normal embryos. Design Retrospective cohort study. Setting University-affiliated infertility center. Patient(s) Preimplantation genetic screening patients (n = 125; n=77 with ET), including cases of repeated implantation failure or recurrent miscarriage. A total of 504 embryos were analyzed. Intervention(s) Embryo culture within a time-lapse system. Main Outcome Measure(s) Kinetic variables included the time to 2 (t2), 3 (t3), 4 (t4), and 5 (t5) cells as well as the length of the second (c…

Impact of preimplantation genetic diagnosis on IVF outcome in implantation failure patients

Implantation failure (IF) is defined as three or more failed IVF attempts, and preimplantation genetic diagnosis (PGD) is being used in these patients to improve IVF outcome. PGD was performed in 49 implantation failure patients with a mean number of 4.2 +/- 1.6 previous IVF failures, and in nine fertile controls. Fluorescence in-situ hybridization (FISH) on blastomeres from biopsied day 3 embryos was performed for chromosomes 13, 16, 18, 21, 22, X and Y. There was a significantly higher rate of chromosomal abnormalities (67.4%) compared with controls (36.3%). In 57 cycles, a pregnancy rate of 34.0% and an implantation rate of 19.8% was observed in implantation failure patients compared wit…