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Genetic and Rare Diseases Information Center (GARD)

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Congenital bilateral absence of the vas deferens

Other Names for this Disease
  • CAVD
  • Congenital bilateral aplasia of vas deferens
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Your Question

Our 34-year-old son was diagnosed with congenital bilateral absence of the vas deferens (CBAVD) resulting from the CFTR mutation. We also have another 31-year-old son and are concerned that he might be affected as well. Is either myself or my husband a carrier? Should we seek medical advice regarding these possibilities?

Our Answer

We have identified the following information that we hope you find helpful. If you still have questions, please contact us.

What is congenital bilateral absence of the vas deferens (CBAVD)?

Congenital bilateral absence of the vas deferens (CBAVD) occurs in males when the tubes that carry sperm out of the testes (vas deferens) fail to develop properly. Although the testes usually develop and function normally, sperm cannot be transported through the vas deferens to become part of semen. As a result, men with this condition are unable to father children (infertile) unless they use assisted reproductive technologies. This condition has not been reported to affect sex drive or sexual performance. This condition can occur alone or as a sign of cystic fibrosis, an inherited disease of the mucus glands. Many men with CBAVD do not have the other characteristic features of cystic fibrosis; however, some men with this condition may experience mild respiratory or digestive problems.[1]
Last updated: 12/22/2011

What causes congenital bilateral absence of the vas deferens (CBAVD)?

More than half of all men with CBAVD have mutations in the CFTR gene. Mutations in this gene also cause cystic fibrosis. When CBAVD occurs with CFTR mutations, it is considered a form of atypical cystic fibrosis. In instances of CBAVD without a mutation in the CFTR gene, the cause of this condition is often unknown. Some cases are associated with other structural problems of the urinary tract.[1]
Last updated: 12/22/2011

How is congenital bilateral absence of the vas deferens (CBAVD) inherited?

When this condition is caused by mutations in the CFTR gene, it is inherited in an autosomal recessive pattern. This pattern of inheritance means that both copies of the gene in each cell have a mutation. Parents of a person with CBAVD each carry one CFTR mutation, but are usually unaffected (carriers). Men with CBAVD who choose to father children through assisted reproduction have an increased risk of having a child with cystic fibrosis. If congenital absence of the vas deferens is not caused by mutations in CFTR, the risk of having children with cystic fibrosis is not increased.[1]

The risk to siblings of a person with CBAVD depends on the affected person's CFTR gene mutation(s) and cannot readily be predicted without this information. Genetic testing is most informative when the CBAVD-causing mutations have been identified in the affected individual. Men with CBAVD sometimes have only one identifiable CFTR mutation, complicating the testing and interpretation of results in their family members.[2] We recommend speaking with a genetics professional about risk to other family members as well as any appropriate genetic testing.
Last updated: 12/22/2011

Is genetic testing available for congenital bilateral absence of the vas deferens (CBAVD)?

GeneTests lists the names of laboratories that are performing genetic testing for CBAVD. To view the contact information for the clinical laboratories conducting testing, click herePlease note:  Most of the laboratories listed through GeneTests do not accept direct contact from patients and their families; therefore, if you are interested in learning more, you will need to work with a health care provider or a genetics professional.  Below, we have provided a list of online resources that can assist you in locating a genetics professional near you.
Last updated: 12/22/2011

How can I find a genetics professional in my area?

Genetics clinics are a source of information for individuals and families regarding genetic conditions, treatment, inheritance, and genetic risks to other family members. More information about genetic consultations is available from Genetics Home Reference. To find a genetics clinic, we recommend that you contact your primary healthcare provider for a referral.

The following online resources can help you find a genetics professional in your community:
Last updated: 10/18/2013