Correction: Embryos of Robertsonian Translocation Carriers Exhibit a Mitotic Interchromosomal Effect That Enhances Genetic Instability during Early Development.

[This corrects the article DOI: 10.1371/journal.pgen.

Sperm Mitochondrial DNA Copy Number Is Not a Predictor of Intracytoplasmic Sperm Injection (ICSI) Cycle Outcomes.

This study is to determine if sperm mitochondrial DNA copy number (mtDNA CN) is associated with fertilization, blastulation, blastocyst euploidy, and live birth rates in in vitro fertilization (IVF) with ICSI cycles. This is a cohort study conducted on stored sperm samples which were collected prospectively and used to create blastocysts transferred in a couple's first ICSI transfer cycle between 2007 and 2013 at a single large infertility center. Samples from ICSI cycles utilizing surgical or cryopreserved sperm or day 3 embryo biopsy were excluded.

Clinical outcomes after the transfer of blastocysts characterized as mosaic by high resolution Next Generation Sequencing- further insights.

Objective: To determine the pregnancy outcome potential of euploid, mosaic and aneuploid embryos.

Design: Retrospective study.

Setting: Reference genetics laboratories.

The cytogenetic constitution of human blastocysts: insights from comprehensive chromosome screening strategies.

Background: Embryos that are able to form blastocysts have succeeded in activating their genome and differentiating into two cell types-an external layer of trophectoderm cells, which will go on to form extra-embryonic tissues such as the placenta, and the inner cell mass, which will give rise to the embryo proper. Culturing embryos to the blastocyst stage has become an increasingly popular IVF practice over the past decade. Additionally, it has been proposed that the identification and transfer of euploid blastocysts could significantly improve IVF outcomes.

Clinical implications of mitochondrial DNA quantification on pregnancy outcomes: a blinded prospective non-selection study.

Study Question: Can quantification of mitochondrial DNA (mtDNA) in trophectoderm (TE) biopsy samples provide information concerning the viability of a blastocyst, potentially enhancing embryo selection and improving IVF treatment outcomes?

Summary Answer: This study demonstrated that euploid blastocysts of good morphology, but with high mtDNA levels had a greatly reduced implantation potential.

What Is Known Already: Better methods of embryo selection leading to IVF outcome improvement are necessary, as the transfer of chromosomally normal embryos of high morphological grade cannot guarantee the establishment of an ongoing pregnancy. The quantity of mtDNA in embryonic cells has been proposed as a new biomarker of viability-higher levels of mtDNA associated with reduced implantation potential.

Detailed investigation into the cytogenetic constitution and pregnancy outcome of replacing mosaic blastocysts detected with the use of high-resolution next-generation sequencing.

Objective: To determine the pregnancy outcome potential of mosaic embryos, detected by means of preimplantation genetic screening (PGS) with the use of next-generation sequencing (NGS).

Design: Retrospective study.

Setting: Genetics laboratories.

Analysis of implantation and ongoing pregnancy rates following the transfer of mosaic diploid-aneuploid blastocysts.

Preimplantation genetic testing for aneuploidy (PGT-A) is widely used in IVF and aims to improve outcomes by avoiding aneuploid embryo transfers. Chromosomal mosaicism is extremely common in early development and could affect the efficacy of PGT-A by causing incorrect embryo classification. Recent innovations have allowed accurate mosaicism detection in trophectoderm samples taken from blastocysts.

Polymorphisms in the MTHFR gene influence embryo viability and the incidence of aneuploidy.

MTHFR is an important enzyme in the metabolism of folic acid and is crucial for reproductive function. Variation in the sequence of MTHFR has been implicated in subfertility, but definitive data are lacking. In the present study, a detailed analysis of two common MTHFR polymorphisms (c.

Mitochondrial DNA Assessment to Determine Oocyte and Embryo Viability.

Mitochondria are the key regulators of multiple vital cellular processes, including apoptosis, calcium homeostasis, and the generation of ATP via the metabolic pathway known as oxidative phosphorylation. Unlike other cellular organelles, mitochondria contain one or more copies of their own genome (mtDNA). The mtDNA encodes a total of 13 genes with critical functions in cellular metabolism.

Altered levels of mitochondrial DNA are associated with female age, aneuploidy, and provide an independent measure of embryonic implantation potential.

Mitochondria play a vital role in embryo development. They are the principal site of energy production and have various other critical cellular functions. Despite the importance of this organelle, little is known about the extent of variation in mitochondrial DNA (mtDNA) between individual human embryos prior to implantation.

Simultaneous assessment of aneuploidy, polymorphisms, and mitochondrial DNA content in human polar bodies and embryos with the use of a novel microarray platform.

Objective: To develop a microarray platform that allows simultaneous assessment of aneuploidy and quantification of mitochondrial DNA (mtDNA) in human polar bodies and embryos.

Design: Optimization and validation applied to cell lines and clinical samples (polar bodies, blastomeres, and trophectoderm biopsies).

Setting: University research laboratory and a preimplantation genetic diagnosis (PGD) reference laboratory.

Clinical utilisation of a rapid low-pass whole genome sequencing technique for the diagnosis of aneuploidy in human embryos prior to implantation.

Background: The majority of human embryos created using in vitro fertilisation (IVF) techniques are aneuploid. Comprehensive chromosome screening methods, applicable to single cells biopsied from preimplantation embryos, allow reliable identification and transfer of euploid embryos. Recently, randomised trials using such methods have indicated that aneuploidy screening improves IVF success rates.

The transcriptome of follicular cells: biological insights and clinical implications for the treatment of infertility.

Background: Oocyte maturation is under strict regulatory control, not only from intrinsic cellular processes, but also extrinsic influences. While the oocyte is directly connected to the surrounding cumulus cells (CCs) via a network of gap junctions facilitating communication and exchange of molecules, it is also influenced by the greater follicular environment. In order to produce an oocyte capable of successfully transmitting the female genetic material and able to support the earliest stages of preimplantation development, cytoplasmic and nuclear maturation must be achieved.

The origin and impact of embryonic aneuploidy.

Despite the clinical importance of aneuploidy, surprisingly little is known concerning its impact during the earliest stages of human development. This study aimed to shed light on the genesis, progression, and survival of different types of chromosome anomaly from the fertilized oocyte through the final stage of preimplantation development (blastocyst). 2,204 oocytes and embryos were examined using comprehensive cytogenetic methodology.