Congenital Absence of the Vas Deferens

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Congenital Absence of the Vas Deferens

What is Congenital Absence of the Vas Deferens?

Congenital absence of the vas deferens (CAVD) happens in men when the tubes that carry sperm out of the testes don't form. CAVD is like being born with a vasectomy – men make normal sperm, but the path to release them is missing.

Although this change is present from birth, a man usually finds out he has CAVD when he sees a doctor because he can't father a child naturally (infertile). CAVD is diagnosed when there are no sperm found in the semen. Doctors can usually tell from a physical exam that the tubes are missing.

CAVD is found in 1% to 2% of men with infertility.

CAVD is caused by gene changes (mutations) most of the time. One of the genes that causes CAVD also causes a genetic disease called cystic fibrosis (CF). The gene mutations that cause CAVD and CF are usually inherited. Each person has two copies of this gene, one from their mother and one from their father. More than half of men with CAVD have mutations in both copies, but some have just one mutation.

CAVD can also be associated with missing kidneys (renal agenesis). When a man has both an absent vas deferens and an absent kidney, it is less likely that the problem was caused by mutations in the CF gene.

Next: What Is Cystic Fibrosis?

Would you change your family planning or test a pregnancy if you knew that there was a higher chance for you to have a child with CF?




CF testing makes the most sense for people who want the information to make different plans for having a family or who would consider prenatal diagnosis for CF. Since you said that you might change your family planning, CF testing may be a good option for you.

There are more choices if testing is done before pregnancy. If you and your partner both have CF gene mutations, you may choose to use donor egg or sperm. If you conceive with your own egg and sperm by in vitro fertilization (IVF), you may consider preimplantation genetic diagnosis. This testing is done on an embryo before it is placed into the mother. Testing can also be done during a pregnancy using CVS or amniocentesis to find out whether the baby has CF. Genetic counseling is available for parents trying to understand a diagnosis and make such decisions.

If you are sure that you would not change your family plans if you were at-risk to have a child with CF, you should consider whether or not CF testing makes sense for you. Finding out that you and your partner both have CF gene mutations means that you have much higher chance to have a child with CF. There are family planning options that can help at-risk couples lower their chances to have a baby with CF, but there are no treatments for CF during pregnancy. All children born in this country are checked for CF shortly after birth. Therefore, if a child is born with CF, the diagnosis is usually made in infancy.

If you and your partner both have CF gene mutations, you would have at least a 25% chance in each pregnancy to have a child with CF. There is no way to know before birth whether that child will have more or less severe health problems. In making your choice about CF testing, consider:

  • Do you think you have the financial, emotional, social and medical resources to care for a child with CF?
  • Would you ever consider egg or sperm donation or preimplantation genetic diagnosis to avoid a pregnancy with CF?
  • If you and your partner conceive with your own egg and sperm, how do you feel about prenatal diagnosis? CVS and amniocentesis can test for CF during pregnancy, but both procedures have a risk for pregnancy loss. How concerned are you about those risks?
  • If you had a prenatal diagnosis of CF, what would you do with that information? Would you want the information to prepare for the birth of a child with special needs? Would you consider ending a pregnancy if you knew the baby would have CF?