Table 2.

Class of CFTR gene mutations: genotype-phenotype correlations [5,69,82,83,84].

Class of Mutation	Class I	Class II	Class III	Class IV	Class V	Class VI
Severity	Severe	Severe	Severe	Mild	Mild	Mild
Type	Nonsense/ Frame-shift	Missense; amino acid deletion	Missense	Missense	Missense splicing defect	Missense
Frequent mutation	G542X, R553X, R1162X, W1282X	G85E, I507del, F508del, N1303K	S549R, G551D, G1349D	R117H, R347P, R334W, R1070W	A455E 3272-26A > G	4326del TC, Gln1412X, 4279insA
CFTR defect	No CFTR synthesis	CFTR trafficking and processing defect	Abnormal channel function, block in regulation; defecting gaiting regulation	Abnormal channel function, decreased conductance	Reduced synthesis of CFTR protein	Decreased protein stability
Potential therapy	Read-throug agents (Ataluren, amynoglicosydes)	Correctors (+Potentiators) Lumacaftor (+Ivacaftor)	Potentiators (Ivacaftor)	Potentiators (Ivacaftor)	Splicing modulators amplifiers	Stabilizers HGF (hepatocyte growth factor)