The Role of Genetics in Infertility and Surrogacy

The Role of Genetics in Infertility and Surrogacy cannot be overemphasized. Many women are not able to conceive and have a baby due to some genetic factors. In some cases, it could be due to inherited chromosomal abnormalities. In other instances, it could be due to a single-gene defect that was passed from the parent to the child. These disorders and diseases happen when the normal DNA sequence is altered partly or as a whole caused by one or multiple gene mutations. If other women in the family have had issues in conception due to factors like premature menopause, endometriosis, polycystic ovary syndrome, etc., the woman in question would also be at an increased risk of these same problems.

Chromosome Abnormalities 

This is a very big issue in embryos, as the ones with these chromosomal abnormalities have very poor implantation rates. Also, when they do implant, a miscarriage occurs and when the pregnancy is carried to term, the baby is born with issues like impaired intellectual function, developmental delay, or physical impairments. Some of the chromosomal abnormalities include:

• Translocation – this is where some chromosomal pieces are attached to the wrong chromosome
• Mutation – this is where there is a change in the gene’s DNA mutation
• Deletion – this is where there is a missing piece of a chromosome
• Inversion – this is a phenomenon where a chromosome is inverted or reversed
• Aneuploidy – this is where there are too few or too many chromosomes

Translocation is the most commonly occurring of the above-listed abnormalities. The parent that is a carrier for this translocation abnormality, while frequently normal, usually has his or her embryo receiving too much or too little genetic material. This usually leads to a failure to implant or a miscarriage. 

Most couples that have been made aware of their chromosomal abnormality will benefit from a preimplantation genetic diagnosis, which is usually carried out as part of an IVF or a surrogacy process. The phenomenon that is referred to as Down syndrome is usually associated with advanced maternal age, and it is also a common example of aneuploidy. Down syndrome is caused by having an extra number of chromosomes. It is also referred to as trisomy.

Inherited genetic disorders

While this is rare, there could be the existence of an inherited genetic disorder due to abnormal genes or mutation. Chromosomal analysis of the parents’ blood shows that this occurs in less than 5% of couples. Single-gene abnormalities are mutations that are caused by changes in the DNA sequence of a gene that produces the proteins that enable the normal working of cells. These gene mutations cause an alteration in the function cells due to a lack of a particular protein. 

Single-gene disorders are usually indicative of a family history of genetic diseases like cystic fibrosis, which is an incurable and fatal disease that affects the mucous glands of vital organs. Though they are quite rare, these diseases can prove to be quite devastating to families. But fortunately, technological advancements have enabled a lot of progress to be made in the detection of these diseases through preimplantation genetic diagnosis done along with IVF. 

IVF and PGD can be used in these conditions to prevent a couple from having disappointments especially when there are known single-gene disorders in the family This can be done even when there are no fertility issues with the couple.

Embryo testing for genetic disorders

This is an option that is presented to couples that are undergoing IVF. During IVF, after fertilization and embryo creation, the embryos are grown in the lab for several days. On the third day of growth, the embryos are usually at the eight-cell stage. One cell is removed from each of the viable embryos and then evaluated for genetic diseases and disorders through preimplantation genetic testing. Preimplantation genetic screening and diagnosis are included in this.

The loss of one cell has been proven not to be a problem and has proven not to prevent any embryonic development. After the testing, the embryos that are proven to be free from any disease are then cleared for transfer to the uterus of the woman. However, since there is a known error rate for preimplantation genetic diagnosis, it is recommended that the woman undergo the normal prenatal testing that is done during pregnancy. Amniocentesis and chronic villus sampling can be performed in addition to PGD, to eliminate any risk of misdiagnosis. The two main benefits that are offered by this preimplantation genetic testing include:

• The decreased risk of passing a genetic disease to a child
• An elevated chance of a successful pregnancy and birth from an IVF treatment with a genetically normal embryo

The embryo that is created through IVF can be tested for single-gene diseases like:

• Sickle cell anemia
• Cystic fibrosis
• Fragile-X syndrome
• Huntington’s disease
• BRCA1 and BRCA2 mutations increase the risk of breast or ovarian cancer in a female child.

Embryos that are possessing of one or more of the above-listed genetic issues will not be chosen for implantation.

The Role of Genetics in Infertility and Surrogacy: Genetic counseling 

Genetic counseling is different from genetic testing in that the genetic counselors help the couple to determine the genetic tests that are most helpful and necessary. This can be screened before conception when the couple is considering PGD. 

Genetic counselors are healthcare providers that are qualified to give the couple vital information concerning the genetic tests and make more informed decisions. They are available to access and examine a couple’s family history and assist in the determination of the cause of infertility. With their expertise, these counselors can be very essential in working with providers to help answer any questions that the couple may have and in most cases reveal the actual cause of the infertility faced by the couple. The determination of the exact genetic issue helps in establishing the most effective treatment which will then improve the outlook on the couple’s quest to have a healthy baby.