Mutations in the cystic fibrosis transmembrane regulator gene and in vivo transepithelial potentials.
OBJECTIVE
To examine the relationship between cystic fibrosis transmembrane regulator gene mutations (CFTR) and in vivo transepithelial potentials.


METHODS
We prospectively evaluated 162 men including 31 healthy subjects, 21 obligate heterozygotes, 60 with congenital bilateral absence of the vas deferens (CBAVD) and 50 with CF by extensive CFTR genotyping, sweat chloride and nasal potential difference testing.


RESULTS
Six (10%) men with CBAVD carried no CFTR mutations, 18 (30%) carried one mutation, including the 5T variant, and 36 (60%) carried mutations on both alleles, for a significantly higher rate carrying one or more mutations than healthy controls (90% versus 19%, p < 0.001). There was an overlapping spectrum of ion channel measurements among the men with CBAVD, ranging from values in the control and obligate heterozygote range at one extreme, to values in the CF range at the other. All pancreatic-sufficient patients with CF and 34 of 36 patients with CBAVD with mutations on both alleles carried at least one mild mutation. However, the distribution of mild mutations in the two groups differed greatly. Genotyping, sweat chloride and nasal potential difference (alone or in combination) excluded CF in all CBAVD men with no mutations. CF was confirmed in 56% and 67% of CBAVD men carrying 1 and 2 CFTR mutations, respectively.


CONCLUSIONS
Abnormalities of CFTR transepithelial function correlate with the number and severity of CFTR gene mutations.
Wilschanski
Michael
M
The Hospital for Sick Children, Toronto, ON, Canada M5G 1X8.
Dupuis
Annie
A
Ellis
Lynda
L
Jarvi
Keith
K
Zielenski
Julian
J
Tullis
Elizabeth
E
Martin
Sheelagh
S
Corey
Mary
M
Tsui
Lap-Chee
LC
Durie
Peter
P
D000483:Alleles; D000584:Amiloride / Q000494:pharmacology; D002712:Chlorides / Q000032:analysis; D003550:Cystic Fibrosis / Q000175:diagnosis / Q000235:genetics*; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics*; D004252:DNA Mutational Analysis; D004847:Epithelial Cells / Q000187:drug effects; D005838:Genotype; D006801:Humans; D008297:Male; D009666:Nose / Q000166:cytology; D011446:Prospective Studies; D026941:Sodium Channel Blockers / Q000494:pharmacology; D013542:Sweat / Q000737:chemistry; D014649:Vas Deferens / Q000002:abnormalities / Q000378:metabolism
D002712:Chlorides; D026941:Sodium Channel Blockers; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D000584:Amiloride