Genetic Counseling and Partner Screening

Before proceeding with fertility treatments, there is one step that is widely considered the most critical in your entire journey: Genetic Counseling and Partner Screening ^[1][2].

Because CBAVD is so closely tied to the CFTR gene, your diagnosis has implications that reach beyond your own health and directly impact the health of your future children ^[3].

Why Partner Screening is the Standard of Care

Men with CBAVD are almost always carriers of at least one (and often two) CFTR mutations ^[4]. While your mutations are likely “mild” enough that they only affected your vas deferens, they can still be passed on to your children ^[2].

The goal of screening your partner is to determine if she is also a carrier of a CFTR mutation ^[5]. About 1 in every 25 to 30 people of Northern European descent are silent carriers of a CFTR mutation without knowing it (though this carrier rate varies significantly by ethnic background) ^[2]. If she is a carrier, the combination of your mutations and hers could lead to a child with classic Cystic Fibrosis (CF)—a serious, life-long condition affecting the lungs and digestion ^[3][6].

It is highly recommended that she undergoes an extended CFTR panel that specifically looks for “mild” variants like the 5T allele—not just a standard, basic CF carrier screen ^[1].

Understanding the Risk Scenarios

A genetic counselor will help you map out the specific risks based on your DNA results. The risk depends entirely on the “dose” of mutations the child receives:

1. Partner is NOT a carrier: The risk of having a child with classic CF is extremely low. Furthermore, because CFTR conditions require a mutation from both parents, any sons you have will simply be healthy carriers like your partner; they will not have CF and they will not have CBAVD ^[2].
2. Partner IS a carrier: This is the high-risk scenario. If your partner also carries a mutation, there is a significant chance (up to 25% or 50%, depending on your specific genetics) that your child could inherit two mutations and be born with classic Cystic Fibrosis ^[4][2].

Your Options: Preimplantation Genetic Testing (PGT)

If both you and your partner are found to be carriers, you do not have to leave the health of your child to chance. Modern medicine offers a way to screen for these mutations before a pregnancy even begins ^[7].

This process is called Preimplantation Genetic Testing for Monogenic Disorders (PGT-M):

• The Process: During an IVF cycle, your embryos are grown in a lab for a few days.
• The Test: A few cells are carefully removed from each embryo and tested specifically for the CFTR mutations identified in you and your partner ^[7].
• The Selection: Only embryos that do not have the high-risk combination of mutations are selected for transfer into the uterus ^[8][9].

Important Expectations: Developing the custom genetic “probes” to test your embryos can add weeks or even months to your IVF timeline, and the testing itself carries additional financial costs. However, couples who use PGT-M have very high success rates, and the clinical outcomes for these pregnancies are generally excellent, comparable to standard IVF ^[8][10].

The Role of the Genetic Counselor

A genetic counselor is a specialist who helps you navigate these complex choices. They don’t just look at lab results; they help you understand the technical details, manage the emotional weight of the diagnosis, and coordinate the specialized testing needed for your embryos ^[11][12].

Meeting with a counselor is not just a “box to check”—it is the foundation for ensuring you can build your family with confidence and peace of mind ^[13].