Alternative Names
CBAVD; CAVD; Absence of vas deferens; Absent vasa; Congenital absence of vas deferens; Congenital aplasia of vas deferens; congenital bilateral absence of vas deferens
Symptoms & Characteristics
Congenital bilateral absence of the vas deferens (CBAVD) occurs in males when the tubes that carry sperm out of the testes (the 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, males 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. Cystic fibrosis causes progressive damage to the respiratory system and chronic digestive system problems. Many males with congenital bilateral absence of the vas deferens do not have the other characteristic features of cystic fibrosis; however, some males with this condition may experience mild respiratory or digestive problems.
Treatment
Males with congenital bilateral absence of the vas deferens may be able to conceive pregnancies using certain assisted reproductive techniques.
How Common Is It?
Congenital bilateral absence of the vas deferens is responsible for 1% to 2% of all infertility in men.
Genetics & Inheritance
More than half of all men with CBAVD have mutations in the CFTR gene. Mutations in this gene also cause cystic fibrosis. When congenital bilateral absence of the vas deferens 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.
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. Men with this condition 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.
Genetic Testing
Clinical genetic testing for mutations in the CFTR gene that cause congenital bilateral absence of the vas deferens may be available through an in person genetic consultation for people who are considered at risk. Use our find a genetic professional directory to locate a trained genetic professional in your area.
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