PRE-IMPLANTATION GENETIC DIAGNOSIS

The Current Status of Pre-Implantation Genetic Diagnosis

The Current Status of Pre-Implantation Genetic Diagnosis

Introduction

In clinical and medical genetics, pre-implantation genetic diagnosis also known as embryo screening, it refers to the process performed on embryos, which takes place before implantation, is some cases it takes place before the fertilization, PGD is an alternative way to diagnose prenatal. It is utilized to identify the particular genetic disease, the benefit of this diagnose helps in avoiding the selected termination of pregnancy as it is the method that creates the possibility that baby can get free from the disease, during the consideration process. Moreover PGD is an attachment, which helps in reproductive technology; it needs vitro fertilization for obtaining embryos and oocytes for evaluation (Sabrina 2010).

In explanation of PGD I discussed that it is a genetic diagnosis form, which is performed before implantation, with this implication oocytes of patients needs to be fertilized in vitro, in this diagnosis embryos remained in culture till diagnosis of disease developed. Moreover it is essential to perform biopsy on embryos, which have been in culture; it helps in obtaining material for performing diagnosis. Pre-implantation genetic diagnosis can be conceded by utilizing various techniques, these techniques depends on the studied condition of nature. Normally, methods based on PCR are utilized for FISH and monogenetic disorders, which help in dealing with the chromosomal abnormalities and in cases where protocol based on PCR is unavailable for a disease linked with sex. These technical aspects requires to be adapted for performing them on blastomeric, moreover it need to be tested thoroughly on model based on single cell prior to clinical use. In the end, after the replacement of embryo, surplus of quality good is not affected, and embryos can be preserved, which needs to transferred and melt back in second cycle (Perez 2011).

1. Biopsy procedures

Pre-implantation genetic diagnosis can be executed on cells, from various developmental stages; the process of biopsy can change accordingly. Theoretically, biopsy can be at every stages of pre implantation, whereas only three of them have been suggested, it includes fertilized and unfertilized oocytes, on the other hand biopsy can be performed on cleavage stage embryos, and blastocysts (Newson 2010).

The process of biopsy also involves two steps, it includes the opening of zona pellucida and exclusion of cells, both of these steps involves two various approaches, it includes chemical, mechanical and laser technology for zona pellucida breaching, aspiration or extrusion for removing the polar bodies herniation, blastomeres, related to the cells of trophectoderm (Landy 2012).

2. Polar body biopsy

The first and second oocytes of polar body are extruded at the concluding time of meiotic division; initially polar body is noted after ovulation and fertilization of second polar body. Biopsy of polar body is utilized mainly by two PGD groups operating in USA and several other groups in different countries where embryo based on cleavage stage selection is not legal. These have been utilized for diagnosing monogenic disorders and translocation of maternal origin and PGS ...