Classification of gene mutations that cause cystic fibrosis (CF)

ClassMutation examplesMutation mechanism
IG542X, W1282XNo functional CFTR protein is synthesised due to the presence of premature termination codons
IIF508delCFTR protein is synthesised but misfolded, keeping it from reaching the apical cell surface
IIIG551D, G1349DFull-length CFTR protein reaching the apical cell surface exhibits abnormal gating (channel persists in the closed state)
IVR117H, R334W, R347PFull-length CFTR protein reaches the apical cell surface but transport of chloride ions is reduced due to channel pore defect
V2789+5G>A, 3849+10kbC>TReduced number of CFTR transcripts due to promoter or splicing abnormalities
VI4326delTC, 4279insADefective CFTR stability at the cell surface; C-terminus mutations result in accelerated turnover

CFTR: CF transmembrane conductance regulator.