Definition

What is preimplantation genetic diagnosis?

• Preimplantation genetic diagnosis (PGD) is an early genetic diagnosis of an IVF embryo prior to its transfer to the uterus. By analyzing DNA from each embryo, normal embryos can be preferentially selected to be transferred into the woman’s uterus.
• PGD helps couples who have an increased risk for a genetic disease conceive a healthy baby.
• PGD promotes healthy pregancies by preventing the transmission of monogenic disorders. It’s an effective method to prevent genetic disorders.

Facts about monogenic disorders

• There are more than 7000 monogenic disorders.
• Monogenic disorders account for 3~5% global population.
• Monogenic disorders may cause premature death, deformity, and disability.

PGD can:

• Help select healthy embryos to transfer, prevent genetic disorders in the off-spring.
• Avoid pregnancy termination, miscarriage and birth defects due to transfer of embryos with genetic abnormalities.

PGD services: 

• S-PGDTM for Monogenic Disorders
• S-PGDTM for Monogenic Disorders+Preimplantation Genetic Screening(PGS)
• S-PGDTM for Monogenic Disorders+PGS+HLA Typing

Principle

Principles of PGD

Haplotype
From SNP information of the parents and the confounder, we can derive the haplotype information of parents and the linked haplotype information of disease genes. With linkage analysis on the sequencing information of the cells form the embryo, normal embryos can then be selected for transferring during IVF.

AmpliSeq

• Multiplex PCR target capturing technology. PCR with 6144 primer pairs in one reaction tube at the same time.
• Only 10 ng of DNA is needed.
• Amplicon with 150 bp are used for amplification. Even degraded samples can be amplified.
• High efficiency and coverage of all targeted fragments.

Benefits

Benefits of PGD

Accurate
The incidence of ADO is reported to be 12.6%. The haplotype technology for genetic linkage analysis can prevent false negative results due to ADO.

Comprehensive analysis
All of 23 pairs of chromosomes will be sequenced in one reaction.

Rapid
It takes only 1 ~ 2 weeks to complete a PGD test.

Flexible
We have developed different panels for a series of monogenic disorders. Panels for other monogenic disorders can be easily developed using our innovative technology for customers.

NGS in PGD monogenic disorders detection, high accuracy, high speed and low cost[1].

Reference
[1] Nathan R. Treff, Ph.D., Anastasia Fedick, B.S., Xin Tao, M.S., Batsal Devkota, Ph.D.,  Deanne Taylor, Ph.D., and Richard T. Scott Jr., M.D.. Evaluation of targeted next-generation sequencing-based preimplantation genetic diagnosis of monogenic disease. Fertil Steril , 2013, 99(5): 1377-1384.

Achievements

Clinical Process

Clinical Process of PGD

5 Steps to perform PGD

1 /Consultation
Advices will be provided to customers within 3 days after genetic information is supplied to our consultant

2 /Pre-PGD
Pre-PGD can be done in 1 week for disorders on our list and 4 weeks for not

3 /IVF sampling
Blastocyst biopsy

4 /PGD
2 weeks

5 /Normal Embryo Transfer

Target Patients

Patients

• For couples who have suffered from monogenic disorders or are carriers of monogenic disorders.
• For couples with genealogical high-risk for monogenic disorders.
• For couples with proband that suffering from monogenic disorders.

Case

HLA Typing + PGD for β-thalassaemia

Background

The couple were both carriers of β-thalassaemia. They had son with severe β-thalassaemia through natural pregnancy.
The couple hoped to have a baby without β-thalassaemia disease through ART and treat the silk boy using umbilical-cord blood (UCB) of the second baby. We thus used PGD test to identify a healthy embryo with HLA type matched to the silk son.

Conclusion: HLA typing showed embryo 4 and embryo 7 matched with the sick boy. But embryo 4 carried HBB gene and was abandoned. Embryo 7 was normal and transferred.

FAQ