Thoughts on Genetic Screening for Egg Donors from Dr. Michael Feinman

April 18th, 2013

Understandably, couples faced with the decision of choosing an egg donor typically have concerns about the donor’s genetic makeup.  Fortunately, there are options available to help a couple identify any genetic disorders their donor might have and reduce the risk of passing these traits on to the child/children born from the donation.

There are two approaches when it comes to donor genetic screening, which are not mutually exclusive.  The first and more traditional approach begins with genetic counseling.  The genetic counselor will take a detailed family history from the donor and recommend specific genetic tests based on this history (and the ethnicity of the donor).  Though this is still considered the standard approach in the industry, it has two potential flaws.  First, the donor may be unaware of a specific genetic disease in her family or, worse, may choose not to disclose it.  Also, single gene testing can be very expensive, especially when it comes to the “Jewish Panel” (performed on Ashkenazi Jewish donors), which can cost over $2,000!

A new alternative that has become more prevalent in recent years is Universal Genetic Testing (UGT).  With UGT, a single saliva or blood sample can be analyzed for the presence of multiple recessive genes at a relatively low cost.  Currently, the first such test available is called “Counsyl.”  This test costs $350 and evaluates 100 recessive traits, including the Ashkenazi panel).

If a serious recessive trait is discovered, the intended father needs to be tested for that gene, or the donor should be excluded.  Most doctors tend to encourage the latter choice.

Critics of UGT are uncomfortable with its “shotgun” approach.  Detection rates for diseases not common in specific ethnic groups can be low, however, these women would not ordinarily be tested for these diseases so not much is really lost.  In contrast, the cystic fibrosis screen in Counsyl contains more mutation than most of the traditional single gene tests currently available.  Also several less-serious diseases (that do not have life-threatening affects) are included in Counsyl, and finding such a disease may unnecessarily create anxiety on the part of the recipient couple.  Some doctors have started customizing the panel to exclude such conditions.   One genetic disorder not included in the Counsyl panel is fragile-X.  Women carrying this mutation can produce boys with severe mental retardation and autism.  Fragile-X is the most common  cause of mental retardation in boys and one of the few proven genetic causes of autism.

Both the traditional approach and UGT are appropriate options for screening egg donors.  I personally recommend Counsyl and fragile-X testing on all new donors.  If for some reason Counsyl is not desired, Caucasian non-Jewish donors are screened for cystic fibrosis, spinal muscular atrophy (SMA), fragile-X, and Tay-Sachs enzyme.  I also recommend that a complete blood count be donor to screen for thalessemia.  As always, your doctor and genetic counselor will be able to help in deciding which genetic tests are most appropriate for your donor.

- Michael Feinman, MD

Medical Director, HRC Fertility