Pgt-M By Using Snp Markers: 5 Years of Experience

Background and aim: pgt (preimplantation genetic testing) is the methodology which makes it possible to do genetic testing on the biopsies taken from an embryo during ifv (in vitro fertilization), prior to implantation into woman’s womb. it is widely used to reduce the risk of miscarriage, to improve ivf success rates and to prevent inheritance of monogenic disease and unbalanced translocations. pgt-m (preimplantation genetic testing for monogenic disorders) is a test which reduces the risk of a couple passing on a specific inherited single gene disorder to their child, before an actual pregnancy is established. str (short tandem repeat) markers are widely used for selecting embryos during pgt-m. snp (single nucleotide polymorphism) markers can also be used for this purpose; although they are not widely used, they are already started to emerge in this field for a couple of advantages on str markers. the advantages include having much higher number of markers in the genome, easier to work on, easier to analyse etc. methods: in setup part of the process, the dna samples from future mother and father, from healthy, sick or deceased child, or any other appropriate member of the family were obtained in order to select markers which were used to track the mutation. after the completion of setup, biopsies from embryos went through wga (whole genome amplification), pcr (polymerase chain reaction) and genotyping. the genotyping gave information about the status of the embryo for the disease of interest and made it possible to select the unaffected embryos before pregnancy was established. results: this study represents 5 years experience of using snp markers for 300 pgt-m cases, on 160 different genes for 1130 embryos. success rate increased from 57% to 90% when 5th day biopsies were used, instead of 3rd day. this 90% success rate further increased to 96%, when the number of markers were increased in each case. conclusion: this study showed that snp markers-based method is a powerful and trustable method for doing pgt-m. 5th day biopsy, with an increased number of markers is a better choice.