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Congenital bilateral absence of vas deferens
Congenital bilateral absence of the vas deferens (CBAVD) is a condition leading to male infertility.
ORPHA:48Classification level: Disorder
- Congenital bilateral agenesis of vas deferens
- Congenital bilateral aplasia of vas deferens
- Prevalence: 1-5 / 10 000
- Inheritance: X-linked recessive or Autosomal recessive
- Age of onset: Adolescent, Adult
- ICD-10: Q55.4
- OMIM: 277180 300985
- UMLS: C0403814
- MeSH: C535984
- GARD: 5461
- MedDRA: 10010670
It accounts for 6% to 8% of cases of obstructive azoospermia and affects about 1/1,000 males. It is also found in 98% of males with cystic fibrosis.
Infertile patients with CBAVD produce small volumes of acidic sperm (<1 ml with a pH<7.0).
In 1990, mutations in the CFTR gene (the causative gene for cystic fibrosis) were identified in 42% of patients in a population of infertile males with CBAVD, suggesting that CBAVD is a genital form of cystic fibrosis. Since then, an exhaustive analysis of the 27 exons of the CFTR gene has led to the classification of CBAVD patients into four groups: i) patients with two mutations in the CFTR gene (19%), ii) patients with one mutation in the CFTR gene and having the IVS8-5T allele in the trans position (33%), iii) patients with either a mutation in the CFTR gene or having the IVS8-5T allele (27%) and iv) patients with neither the IVS8-5T allele nor a mutation in the CFTR gene (21%).
The condition is transmitted as an autosomal dominant trait. The genetic data have important implications for genetic counselling: the method of intracytoplasmic microinjection of a single spermatozoon has successfully resolved the male infertility problem. However, the identification of a CFTR mutation in a CBAVD patient implies that a CFTR mutation in the patient's partner should be sought, as if a mutation is found, preimplantation or prenatal diagnosis can be proposed.
- Clinical genetics review
- English (2017)