Lab Touring - PGS, Preimplantation Genetic Screening by next-generation sequencig (NGS)
July 13, 2015
The traditional prenatal examinations include chorionic villus sampling (CVS) and amniocentesis. However, the induction would be required if either CVS or amniocentesis revealed significant chromosomal abnormalities, and it becomes psychological stress. Perimplantation Genetic Screening（PGS）is an advanced technology, combining IVF and cell molecular biology, taking the third day embryo (about 6-10 cells now) or the 5th day blastocyst cell for chromosome analysis. The widely used analysis platform is based on array comprehensive hybridization (aCGH), but the recent researches reported that the next-generation sequencing platform performs better resolution and sensitivity. In addition, the low-rate aneuploidy is displayed more clearly in the NGS than in the aCGH.
Technique | NGS | aCGH | |||
Resolution | Diagnosed range: affected length>10Mb Detected range: affected length >2Mb | Diagnosed range: affected length>10Mb | |||
Application | 1. Frequent early abortion 2. Repeated failure in IVF 3. Advanced maternal age 4. Undefined infertility 5. Severe male infertile factor | ||||
Embryo stage | D5/D6 good blastocyst (≧BB)  | ||||
Accuracy | 90% | 90% | |||
Embryo transfer | Warmly thawed embryo transfer | ||||
Prenatal exam | Amniocentesis is recommended | Amniocentesis is recommended | |||
The aneuploid rate increases with the maternal age.
The general exam procedure of PGS is showed in the following figure,
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