Cystic fibrosis mutations for p.F508del compound heterozygotes predict sweat chloride levels and pancreatic sufficiency.
Cystic fibrosis (CF) is a monogenetic disease with a complex phenotype. Over 1500 mutations in the CFTR gene have been identified; however, the p.F508del mutation is most common. There has been limited correlation between the CFTR mutation genotype and the disease phenotypes. We evaluated the non-p.F508del mutation of 108 p.F508del compound heterozygotes using the biological classification method, Grantham and Sorting Intolerant from Tolerant (SIFT) scores to assess whether these scoring systems correlated with sweat chloride levels, pancreatic sufficiency, predicted FEV(1) , and risk of infection with Pseudomonas aeruginosa in the last year. Mutations predicted to be 'mild' by the biological classification method are associated with more normal sweat chloride levels (p < 0.001), pancreatic sufficiency (p < 0.001) and decreased risk of infection with Pseudomonas in the last year (p = 0.014). Lower Grantham scores are associated with more normal sweat chloride levels (p < 0.001), and pancreatic sufficiency (p = 0.014). Higher SIFT scores are associated with more normal sweat chloride levels (p < 0.001) and pancreatic sufficiency (p = 0.011). There was no association between pulmonary function measured by predicted FEV(1) and the biological classification (p = 0.98), Grantham (p = 0.28) or SIFT scores (p = 0.62), which suggests the pulmonary disease related to CF may involve other modifier genes and environmental factors.
Institute for Human Genetics, Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA 94143, USA. ronnie.sebro@radiology.ucsf.edu
R
R
Sebro
H
H
Levy
K
K
Schneck
D
D
Dimmock
B A
BA
Raby
C L
CL
Cannon
U
U
Broeckel
N J
NJ
Risch
D002712:Chlorides / Q000032:analysis; D003550:Cystic Fibrosis / Q000235:genetics* / Q000503:physiopathology; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000145:classification / Q000235:genetics*; D005838:Genotype; D006579:Heterozygote; D006801:Humans; D016014:Linear Models; D008404:Massachusetts; D010179:Pancreas / Q000503:physiopathology*; D010641:Phenotype; D011552:Pseudomonas Infections / Q000453:epidemiology; D012307:Risk Factors; D017384:Sequence Deletion / Q000235:genetics*; D013542:Sweat / Q000737:chemistry*
C505032:CFTR protein, human; D002712:Chlorides; D019005:Cystic Fibrosis Transmembrane Conductance Regulator