CFTR Mutations in Congenital Absence of Vas Deferens

A qualitative diagnosis of infertility requires attention to female and male physical abnormalities, endocrine anomalies and genetic conditions that interfere with reproduction. Many genes are likely to be involved in the complex process of reproduction. Cystic fibrosis (CF) incidence varies in different White people populations (a higher incidence of CF is observed in northern–western European populations than in southern European populations), and therefore the incidence of congenital bilateral absence of the vas deferens (CBAVD) may also vary in different White people populations. As CF is mainly observed in White people, hardly any data are available of CBAVD in non-White people, but frequent polymorphisms such as 5T are observed in most populations. The spectrum and distribution of cystic fibrosis transmembrane conductance regulator gene (CFTR) mutations differs between CBAVD and CF patients, and even compared with control individuals. Combinations of particular alleles at several polymorphic loci yield insufficient functional CFTR. The combination of the 5T allele in one copy of the CFTR gene with a cystic fibrosis mutation in the other copy is the most common cause of CBAVD in Iran. Because of techniques such as intracytoplasmic sperm injection (ICSI), CBAVD patients are now able to father children, however such couples have an increased risk of having a child with cystic fibrosis, and therefore genetic testing and counseling should be provided. Around 10% of obstructive azoospermia is congenital and is due to mutations the CF gene. This paper reviews the relationship of mutations in the CFTR gene with CBAVD.