Genetic Testing for Egg Donors: What’s Required?

The health of the child is central to fertility treatments and it begins with the egg donor. A lesser talked about yet crucial part of ensuring this is the egg donor genetic testing. Despite it looking and feeling daunting, genetic testing is about preparedness, safety and reducing risks. Every egg carries the promise of a potential child as well as entire biological histories of every person that came before them. They carry biological information and instructions that could contain just about anything. These instructions and information are what genetic testing gets to.

Any talk about genetics necessitates that we get back to the basics. So, what is genetics? Genetics are studies of genes as the most basic and fundamental units of inherited biological traits. Basically anything related to genes are referred to as genetics. Genes themselves are the biological programming behind any individual living thing. Like a complex code, building up into a life form. Genetic testing, also called DNA testing, analyses the genes (DNA make up) and identifies the variations associated with certain traits, characteristics and/or disorders.
 

Let us delve in to understand genetic testing, why genetics matter and why testing is necessary for egg donors. We will get to understand what it involves and how it affects the whole process, especially eligibility, of egg donation. 

Why Genetic Testing Is Necessary

Genetic testing ensures the health and safety of children conceived through fertility treatment. Genes are the blueprint for the body. Traits and characteristics are passed down from parent to offspring such as blood type, hair and eye color as well as certain health conditions. Genes come in many variations, usually doubles attained from either parent. Both can get expressed, combining to create a unique expression of a trait. In other cases, only one of the variations can and will get expressed. The expressed variation in this case is referred to as the dominant trait while the unexpressed is called the recessive trait. 

A gene could be recessive in a parent and fail to be expressed but due to interactions with the other parent’s genetic material can and/or does get expressed in the child. Sometimes, a change (mutation) occurs in the parent’s DNA where it fails to be expressed but is passed down to the child and does get expressed. Genetic testing screens and evaluates genes to identify any potential conditions and disorders that can be passed down to the child or impact fertility and pregnancy. 

As an egg donor, you contribute to one half of the offspring's genetic material. There are traits and therefore conditions that are specific to gender. That is they are carried by the X chromosome. Females have two X chromosomes while males have XY. As the egg donor, you contribute one X chromosome to the donor-conceived child. 

Genetic testing is geared towards preventing genetic disorders in the donor-conceived child. It also offers informed decision making for all parties involved, from the egg donor to recipient as well as clinics. 

Common Genetic Screenings for Donors

Genetic screening is rather straightforward for the egg donor. It includes giving a detailed medical history of the egg donor (both personal medical history and that of the family are necessary in this case). Next a sample is collected, it could be a saliva swab or a small sample of blood is drawn. The heavy lifting is done in the next part, where the sample is taken to the lab for analysis and results. Finally, counselling is given based on the genetic testing results. The tests include: 

Karyotyping (chromosomal testing)

A test examining the number and structure of the DNA. It marks out any chromosomal abnormalities such as an extra or missing  chromosome; deletion, duplication, mispositioning or misplacement of chromosomes. It leads to diseases such as Down, Turner and Klinefelter syndromes.

Carrier screening

A test examining recessive genes that could cause moderate to severe, childhood on-set diseases, that shorten life expectancy or cause disability and have no treatments. Sometimes comparatively milder, adult on-set diseases and treatable ones are identified as well. These conditions include: 

• Cystic Fibrosis: A condition that affects the lungs and digestive system leading to over production of thick sticky mucus that coats the lungs leading to difficulty in breathing. 
• Spinal Muscular Atrophy: A number of genetic diseases that affect motor neurons, leading to muscle weakness and loss of movement. 
• Tay-sachs disease: A disorder affecting the nervous system and can be fatal in childhood.
• Thalassemia and Sickle Cell disease : A group of blood disorders that affects hemoglobin leading to anemia. 
• Fragile X- Syndrome: Causes developmental impairments like intellectual disabilities, behavioral and learning challenges and certain distinct physical characteristics. 
• Other X- Linked conditions: These are a number of conditions and disorders caused by mutations and changes in the X chromosome. Majorly include but are not limited to: Vitamin D resistant rickets, Reff syndrome, Incontinentia pigmentia. 
  

How Results Impact Eligibility

It is important that the egg donor understands the purpose for the screening as well the implications of the results which greatly determine egg donor eligibility. Although the results are not cast in stone and vary based on a number of factors. The conditions, if any found and how they may interact with the father’s own genetics matters most. How does it play out?

• A carrier status implies that the potential egg donor carries a certain recessive condition. If the intended father is not a carrier, then the combined results will not be problematic. They can go on to donate successfully. 
• A multiple carrier status implies that the potential egg donor carries several conditions and/or has a rather complex family medical history. This significantly raises the risk factors and requires more caution. A highly informed consultation is needed before any decisions are made. 
• Dominant genetic conditions can be identified in the process. This applies in cases where the potential egg donor carries a gene where just one copy is enough to cause serious disorders. In this case the egg donor is disqualified since the risks involved are too great. 
• Variants of uncertain significance (VUS) are a grey area where there isn’t enough information to determine whether it is safe or harmful. In such cases, each is evaluated by professionals individually. 
  

Every clinic has its own unique experience to offer and set of requirements to consider. What is acceptable for one clinic may be non-negotiable for another. 

Genetic testing as a requirement is simply a safety measure in the egg donation process. It ensures that any avoidable circumstance can and will be avoided while making the process easier for the egg recipient. It is not intended to condemn or label any potential egg donor as flawed. It is geared to simply arm all parties with necessary facts, creating clarity and allowing for better decision making. 

Our fertility specialists at Fertility Associate of Memphis (FAM) are always available to guide you every step of the way. Why not book your appointment today to empower yourself as you gift another family the chance of parenthood.   

FAQ

Why do egg donors undergo genetic testing?

To screen for any genetic conditions and disorders that could be passed on to the child. It works to ensure the health of the child. 

What happens if a genetic issue is found?

Depending on the severity of any conditions found, the results could disqualify some egg donors.