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Preimplantation Genetic Testing for Aneuploidies: Where We Are and Where We're Going
Published in Darren K. Griffin, Gary L. Harton, Preimplantation Genetic Testing, 2020
Andrea Victor, Cagri Ogur, Alan Thornhill, Darren K. Griffin
Hybrid WGA techniques combine MDA and LA-PCR methodologies, like multiple annealing and looping-based amplification cycles (MALBAC). An initial isothermal amplification of denatured template is performed using specific MALBAC primers, followed by PCR amplification of the DNA-MALBAC primer fragments. Hybrid methods, though more labor intensive than standard MDA, offer reasonable uniformity across the genome [57–60].
Clinical application of NGS-based SNP haplotyping for the preimplantation genetic diagnosis of primary open angle glaucoma
Published in Systems Biology in Reproductive Medicine, 2019
Xingzhe Ji, Zhou Zhang, Juanzi Shi, Bin He
Preimplantation genetic diagnosis (PGD) has been used to select unaffected embryos from patients suffering from known genetic diseases. PGD is a more superior method than prenatal diagnosis because the former can avoid the pain of pregnancy termination if the foetus is affected and is also more ethically acceptable. POAG caused by MYOC mutations is an autosomal dominant disorder. To our knowledge, the most efficient method to detect the gene mutation is Sanger sequencing. However, two inherent defects are observed in Sanger sequencing for whole genome amplification (WGA) products from biopsied cells. Firstly, WGA techniques are unable to cover the whole genome, causing a risk of sequencing failure. Secondly, there is the risk of allele dropout (ADO) caused by amplification bias. Currently, multiple annealing and looping based amplification cycle (MALBAC) is applied to WGA to reduce the bias of amplification and cover the whole genome (Bourcy et al. 2014; Deleye et al. 2015). However, ADO still occurs in some instances. Since 2006, preimplantation genetic haplotyping analysis of polymorphic markers flanking the mutation site via next-generation sequencing (NGS) has been used in PGD to determine ADO and avoid misdiagnosis (Renwick et al. 2006, 2010; Hao et al. 2018).