title: Characterization of cystic fibrosis conductance transmembrane regulator gene mutations and IVS8 poly(T) variants in Portuguese patients with congenital absence of the vas deferens.
abstract: BACKGROUND
  Cystic fibrosis conductance transmembrane regulator (CFTR) gene mutations and IVS8 poly(T) variants in Portuguese patients with bilateral (CBAVD) and unilateral (CUAVD) congenital absence of the vas deferens remain to be evaluated.
  
  
  METHODS
  Patient screening was carried out by PCR, denaturing gradient gel electrophoresis and DNA sequencing.
  
  
  RESULTS
  CFTR mutations were found in 18 out of 31 (58.1%) CBAVD and in three of four (75%) CUAVD patients. The most frequent mutations were F508del and R334W in CBAVD and G542X in CUAVD, with the allelic frequencies of R334W (6.5%) and G542X (25%) being particular to the Portuguese population. The 5T allelic frequency was 3.5% in the fertile male population, 25% in CUAVD and 27.4% in CBAVD patients. The combined frequency of mutations (CFTR+5T) was increased in CBAVD to 22 out of 31 (71%). The frequency of CFTR mutations was compared with that of patients with secondary obstructive azoospermia (OAZ; one out of 16, 6.3%) and non-obstructive azoospermia (NOAZ; two out of 22, 9.1%) with conserved spermatogenesis, which were similar to the general population. However, whereas the 5T allelic frequency in OAZ was similar to that of the general population (3.1%), it was increased in NOAZ cases (14.3%).
  
  
  CONCLUSIONS
  Data confirm that CFTR+5T mutations represent the most common genetic abnormality in CAVD, and suggest that cases of NOAZ may be associated with the 5T allele.
authors.affiliation: Department of Genetics, Faculty of Medicine, Laboratory of Cell Biology, ICBAS, University of Porto, Centre for Reproductive Genetics Alberto Barros, Porto, Portugal.
authors.forename: Ana
authors.initials: A
authors.lastname: Grangeia
authors.forename: Florence
authors.initials: F
authors.lastname: Niel
authors.forename: Filipa
authors.initials: F
authors.lastname: Carvalho
authors.forename: Susana
authors.initials: S
authors.lastname: Fernandes
authors.forename: Azarnouche
authors.initials: A
authors.lastname: Ardalan
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Girodon
authors.forename: Joaquina
authors.initials: J
authors.lastname: Silva
authors.forename: Luis
authors.initials: L
authors.lastname: Ferrás
authors.forename: Mário
authors.initials: M
authors.lastname: Sousa
authors.forename: Alberto
authors.initials: A
authors.lastname: Barros
mesh_terms: D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics*; D005787:Gene Frequency; D006801:Humans; D007248:Infertility, Male / Q000235:genetics* / Q000473:pathology; D007668:Kidney / Q000002:abnormalities / Q000473:pathology; D008297:Male; D009154:Mutation; D009845:Oligospermia / Q000235:genetics; D011071:Poly T; D011174:Portugal; D012016:Reference Values; D014649:Vas Deferens / Q000002:abnormalities*
chemical_list: C505032:CFTR protein, human; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D011071:Poly T