title: The TNFalpha receptor TNFRSF1A and genes encoding the amiloride-sensitive sodium channel ENaC as modulators in cystic fibrosis.
abstract: The CFTR mutations in cystic fibrosis (CF) lead to ion transport anomalities which predispose to chronic infection and inflammation of CF airways as the major determinants for morbidity and mortality in CF. Discordant clinical phenotypes of siblings with identical CFTR mutations and the large variability of clinical manifestations of patients who are homozygous for the most common mutation F508del suggest that both environment and genes other than CFTR contribute substantially to CF disease. The prime candidates for genetic modifiers in CF are elements of host defence such as the TNFalpha receptor and of ion transport such as the amiloride-sensitive epithelial sodium channel ENaC, both of which are encoded side by side on 12p13 (TNFRSF1A, SCNN1A) and 16p12 (SCNN1B, SCNN1G). Thirty-seven families with F508del-CFTR homozygous siblings exhibiting extreme clinical phenotypes that had been selected from the 467 pairs of the European CF Twin and Sibling Study were genotyped at 12p13 and 16p12 markers. The ENaC was identified as a modulator of CF by transmission disequilibrium at SCNN1G and association with CF phenotype intrapair discordance at SCNN1B. Family-based and case-control analyses and sequencing of SCNN1A and TNFRSF1A uncovered an association of the TNFRSF1A intron 1 haplotype with disease severity. Carriers of risk haplotypes were underrepresented suggesting a strong impact of both loci on survival. The finding that TNFRSF1A, SCNN1B and SCNN1G are clinically relevant modulators of CF disease supports current concepts that the depletion of airway surface liquid and inadequate host inflammatory responses trigger pulmonary disease in CF.
authors.affiliation: Department of Pediatrics, OE6711, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany. mekus.frauke@mh-hannover.de
authors.forename: Frauke
authors.initials: F
authors.lastname: Stanke
authors.forename: Tim
authors.initials: T
authors.lastname: Becker
authors.forename: Harry
authors.initials: H
authors.lastname: Cuppens
authors.forename: Vinod
authors.initials: V
authors.lastname: Kumar
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Cassiman
authors.forename: Silke
authors.initials: S
authors.lastname: Jansen
authors.forename: Dragica
authors.initials: D
authors.lastname: Radojkovic
authors.forename: Benny
authors.initials: B
authors.lastname: Siebert
authors.forename: Jennifer
authors.initials: J
authors.lastname: Yarden
authors.forename: David W
authors.initials: DW
authors.lastname: Ussery
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Wienker
authors.forename: Burkhard
authors.initials: B
authors.lastname: Tümmler
mesh_terms: D000293:Adolescent; D000328:Adult; D002881:Chromosomes, Human, Pair 12; D002885:Chromosomes, Human, Pair 16; D003550:Cystic Fibrosis / Q000235:genetics*; D053503:Epithelial Sodium Channels / Q000235:genetics* / Q000502:physiology*; D005190:Family; D005260:Female; D005787:Gene Frequency; D006239:Haplotypes; D006801:Humans; D015810:Linkage Disequilibrium; D008297:Male; D008875:Middle Aged; D047888:Receptors, Tumor Necrosis Factor, Type I / Q000235:genetics* / Q000502:physiology*; D017422:Sequence Analysis, DNA; D035781:Siblings
chemical_list: D053503:Epithelial Sodium Channels; D047888:Receptors, Tumor Necrosis Factor, Type I; C507045:SCNN1A protein, human; C506235:TNFRSF1A protein, human