Our Equipment & TechnologyPre-implantation Genetic Testing for Aneuploidies – Abnormal Number of Chromosomes (PGT-A) or Pre-implantation Genetic Testing for Monogenic Diseases / Chromosomal Structural Rearrangements (PGT-M/SR)

Pre-implantation Genetic Testing for Aneuploidies – Abnormal Number of Chromosomes (PGT-A)
Pre-implantation Genetic Testing for Monogenic Diseases / Chromosomal Structural Rearrangements (PGT-M/SR)

Embryo Biopsy
To perform PGT-A or PGT-M/SR, it is necessary to remove one or more cells (embryo biopsy) from the embryo to perform the tests. Embryo biopsy can be done from a day 3 embryo (blastomere biopsy) or from a day 5 blastocyst (trophectoderm biopsy).

Day 3 Blastomere biopsy

Day 5 Trophectoderm biopsy

Embryo Transfer / Cryopreserved
Embryos unaffected by the genetic diseases or with normal number of chromosomes can either be transferred or cryopreserved.

Risks Involved with PGT-A or PGT-M/SR

• The accuracy of PGT-A or PGT-M/SR may not be 100%. This is because the number of chromosomes in the cells removed from the embryo may not be the same as those of the other cells of that particular embryo. Therefore, prenatal diagnosis is still recommended for pregnancy after PGT-A or PGT-M/SR
• Possibility that no embryos are suitable for transfer
• Some embryos will have no diagnosis, due to poor DNA quality
• Some embryos may be damaged in the process of cell removal

* Remark:
Next-Generation Sequencing (NGS) –First used in Hong Kong
NGS is an emerging technology that provides the opportunity to simultaneously analyze and perform an extensive comprehensive chromosome screening / diagnosis by concurrently sequencing, counting, and accurately assembling millions of DNA reads. Compared with other testing methods, NGS may have advantages and hence the potential to be universally adopted in PGT-A or PGT-M/SR in the future.

IVF Centre of Hong Kong Sanatorium & Hospital was the first in Hong Kong to use Next-Generation Sequencing for PGT-A or PGT-M/SR.

Embryo with Down Syndrome the presence of a third copy of chromosome 21

Normal Embryo (male) 23 pairs of chromosomes with XY