You’ve been told that you are fertile, except for a genetic disorder in the family that has turned it upside down. Or perhaps you’ve suffered miscarriages for which there’s no real explanation. Genetic testing is the road to a healthy pregnancy for many couples, and in this case, it is called PGT-M. This is the guide that helps you understand the circumstances in which you should go for a PGT test in Noida.
What Is PGT-M?
PGT-M: Preimplantation genetic testing for monogenic disorders. It is a special genetic test conducted on embryonic cells before transferring the embryo to the uterus during an IVF cycle.
PGT-M differs from PGT-A, which is used to test if the chromosomal number is wrong, as it tests for known, inherited conditions related to mutations in one of the genes. It is only recommended if there is a known genetic risk in one or both partners.
Are You or Your Partner a Carrier of an Inherited Genetic Condition?
The most common indication for PGT-M is carrier status. Many people will have only one copy of a gene defect and not get the disease themselves, but if both parents have the same recessive gene, then there is a 25% chance that each pregnancy will result in the child having the disease.
Some of the conditions that are commonly screened with PGT-M include:
- Thalassaemia is one of the most common inherited blood disorders in India, especially in certain communities in the region.
- Sickle Cell Disease (SCD) is a blood disease characterised by a problem with oxygen transport to the body.
- The lungs and digestive system are primarily affected in CF disease.
- Spinal Muscular Atrophy (SMA) is a progressive neuromuscular disorder.
- Fragile X Syndrome is one of the top causes of inherited intellectual disability
A PGT test before embryo transfer is very recommended in the case of both partners being victims of a recessive mutation, as identified by genetic carrier screening.
Have You Experienced Recurrent Pregnancy Loss?
Sometimes, single-gene conditions are inherited that are associated with recurrent miscarriage (two or more consecutive pregnancy losses). The use of PGT-A is to identify chromosomal causes of miscarriage; however, PGT-M is recommended if a specific monogenic disorder is known to be a contributing factor found through genetic investigation.
Does Your Family History Include a Dominant Genetic Disorder?
Some genetic disorders are autosomal dominant, which means that only one copy of the defective gene is required for the disorder. In these situations, a parent with the disease has a 50% chance of passing it on to any child they have.
This category contains the following conditions:
- Huntington’s disease is a progressive neurological disorder which presents in adulthood.
- BRCA1/BRCA2 mutations: marked increase in the risk of breast and ovarian cancers throughout life.
- Myotonic dystrophy affecting muscles and multiple organ systems
- Marfan Syndrome, which is a connective tissue disease
PGT-M eliminates the hesitation in the process of each transfer decision for couples where one partner has the dominant mutation.
Are You in a Consanguineous Relationship?
Inbreeding marriages (which are more prevalent in some communities in India) have a greater statistical likelihood that both prospective husbands and wives will have the same recessive gene mutations. In such cases, it is often advised to undergo carrier screening followed by PGT-M prior to having children via IVF.
How Is PGT-M Different From Standard Genetic Counselling?
Genetic counselling is the process of determining risk. PGT-M acts on it.
Counselling gives you the likelihood that your child could develop a condition. PGT-M is a test performed on every embryo produced in your IVF cycle, and only healthy embryos are selected before pregnancy starts. The two go hand-in-hand: counselling drives the decision, and PGT-M acts at the embryological level.
How Is PGT-M Performed?
These are the steps of the process:
- Carrier testing and genetic counselling are available for both partners to confirm the type of mutation
- The genetic probe is customised for that specific mutation – preparation takes 4-8 weeks
- The IVF stimulation and egg retrieval are continued normally.
- On Day 5 or 6, embryos are cultured to the blastocyst stage.
- The embryologist takes a few cells from the outer tissue of the blastocysts (trophectoderm biopsy)
- Cells are sent to a specialised genetics lab for analysis
- Embryos that are not affected are identified and frozen for future use in a frozen embryo transfer.
Conclusion
The use of PGT-M is not a standard procedure in all IVF cycles, but for couples with an established genetic disease, it is one of the strongest tools available to prevent the birth of a new family member who will suffer from the disease. The initial step is to determine if you are in one of the above-mentioned risk categories.
To schedule a consultation with a clinical embryologist who has a background in performing embryo biopsy and more than 1200 PGT procedures, contact embryologist.co.in and take the wisest steps towards a healthy pregnancy.