Case of Preimplantation Genetic Testing (PGT) in Metabolic disorder
Mrs. M*, a 38-year-old lady visited Nova IVF Fertility, Chembur, Mumbai in the 2nd half of 2020 for a special medical condition. They had a child diagnosed with a metabolic disorder called methylmalonic acidemia, who passed away battling the metabolic disorder.
The couple was later tested to be carriers of the gene responsible for this mutation. They had undergone genetic counseling and were advised of the options of Preimplantation genetic testing or trying naturally with an early pregnancy test for the disorder in a future pregnancy.
The couple did not wish to go through the trauma again and opted for PGT.
What is a PGT?
When present in one copy, the mutation causes a person to be a carrier of a metabolic disorder. When present in 2 copies (one from each parent), it causes metabolic disease, affecting multiple body systems, and is not compatible with a healthy life.
PGT-M is a procedure performed to know whether a mutation is there in DNA or not. PGT-A is a procedure that checked for age related aneuploidies in the chromosome of an embryo. When offered together they will help decide the finest embryos to transfer to avoid failed transfer, miscarriages, or chromosomal abnormalities in babies.
Exploring the possibilities: PGT-M/ A
Dr. Richa Jagtap, IVF & Fertility Specialist at Nova IVF, Chembur expertly counseled the couple about the solutions they can explore. She suggested that Mrs. M undergo intracytoplasmic sperm injection (ICSI), PGT- M and PGT- A would be done on all resulting embryos to select the normal one for transferring back into the uterus.
Procedure: A general workup and detailed genetic counseling were recommended, keeping in mind the patient’s advanced age. The pre-PGT-M (PGT for single gene disorder) workup was done. The couple started the treatment after it was confirmed that the single gene defect could be detected in their embryos.
They were keen to do a genetic test to find disease-free embryos and then test those embryos for any chromosomal aneuploidies known to arise due to advanced maternal age called PGT-A (PGT to test aneuploidies in embryo)
The intracytoplasmic sperm injection (ICSI) was done, and resultant embryos were cultured to a blastocyst stage. Biopsy was done for the best embryos, after which they were frozen individually.
The test results came back identifying normal embryos and carriers for the said mutation.
A normal blastocyst was transferred. The patient conceived and has a healthy ongoing pregnancy in the 2 trimester currently.
They still have some embryos frozen for future use if they so wish for.
Additional Requirements: The patient underwent an office Hysteroscopy to evaluate the uterine cavity before planning embryo transfer, where minor adhesions and micro polyps were removed. This prepared the uterus to receive the embryo.
For older women starting their fertility journey, there is a stronger possibility of aneuploidy or random chromosomal errors in the egg cell. Parents can select a supplementary PGT procedure (PGT-A) for an aneuploid test.
For couples who carry a mutation that can lead to an abnormal offspring, PGT-M comes as a boon!
Risks: No matter how minimal, PGT does involve certain risks.
1. Embryos are delicate, so any procedure consists of embryo handling and poses the risk of harm. However, the overall risk of injury to the embryo is negligible.
2. While testing, a sample of cells from the embryo demonstrates all the cells in the embryo. Testing of embryos that show mosaicism can give inexact or uncertain outcomes.
3. Sometimes, the test can not determine whether the embryo's genetic material is normal or abnormal. It may be due to various reasons, including a poor-quality embryo.
Making an informed decision to pursue PGT
Every medical procedure has its pros and cons. Accordingly, the couple must consider all the aspects of a procedure before deciding. Dr. Richa Jagtap at Nova IVF Chembur, Mumbai explained how PGT is an excellent option for couples with inherited single-gene disorders.
They were blessed enough to get a positive result after the very first cycle. The pregnancy ensued without any complications, and Mrs. M is in her 2 trimester currently.
The couple was extremely grateful to Dr. Richa Jagtap and the entire Nova IVF team for helping them complete their family. We are glad to have gotten the chance to ease their pain by giving them another shot at joy.
Never lose hope in the face of adversity.
Your second chance at happiness is out there.
The client names have been withheld to protect their identity.