title: Cystic fibrosis modifier genes related to Pseudomonas aeruginosa infection.
abstract: Cystic fibrosis (CF) is one of the most common life-shortening genetic disorders, and the CF transmembrane conductance regulator (CFTR) is the major causal gene. However, a substantial clinical variability among patients with identical CFTR genotypes suggests the presence of modifier genes. We tested the effect of four genes involved in Pseudomonas aeruginosa infection. Analysis of a primary cohort detected eight candidate polymorphisms that were genotyped in the secondary cohort of 1579 patients; lung function and age at first infection with P. aeruginosa were considered as the phenotypes. Both additive and codominant models were considered, adjusting for confounding variables but not for multiple comparisons. In the secondary cohort, heme oxygenase-1 (HMOX1) rs2071749 had the most significant effect on lung function in the pediatric group (P=0.01; P(corrected)=0.03), and complement factor 3 (C3) rs11569393 and HMOX1 rs2071746 in the adult groups (P=0.03 for both variants; P(corrected)=0.16, 0.09). No polymorphism of complement factor B (CFB) or toll-like receptor 4 (TLR4) had a significant modifying effect on lung function in either group. We have identified two genes that showed nominal association with disease severity among CF patients. However, because of the multiple comparisons made, further studies are required to confirm the interaction between these modifying genes and CFTR.
authors.affiliation: James Hogg Research Centre, Providence Heart+Lung Institute, St Paul's Hospital, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: J E
authors.initials: JE
authors.lastname: Park
authors.forename: R
authors.initials: R
authors.lastname: Yung
authors.forename: D
authors.initials: D
authors.lastname: Stefanowicz
authors.forename: K
authors.initials: K
authors.lastname: Shumansky
authors.forename: L
authors.initials: L
authors.lastname: Akhabir
authors.forename: P R
authors.initials: PR
authors.lastname: Durie
authors.forename: M
authors.initials: M
authors.lastname: Corey
authors.forename: J
authors.initials: J
authors.lastname: Zielenski
authors.forename: R
authors.initials: R
authors.lastname: Dorfman
authors.forename: D
authors.initials: D
authors.lastname: Daley
authors.forename: A J
authors.initials: AJ
authors.lastname: Sandford
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000483:Alleles; D002648:Child; D002675:Child, Preschool; D003550:Cystic Fibrosis / Q000150:complications / Q000235:genetics* / Q000382:microbiology; D005260:Female; D060045:Genes, Modifier; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D015201:Meta-Analysis as Topic; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D011552:Pseudomonas Infections / Q000209:etiology / Q000235:genetics* / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000502:physiology; D055815:Young Adult