Table 1.

Classification of CTFR mutations, their impact on the protein.

Mutation class	Class 1	Class 2	Class 3	Class 4	Class 5	Class 6
Common mutations	G542X	F508del	G551D	R117H	A455E	4326deITC
	Gly542X	N1303K	G551S	R334W	2789 + 5G-A	N287Y
Frequency (%)	10%	70%	4%	3%	3%
Disfunction	No stable RNA	CTFR trafficking defects	Defective CTFR regulation	Decreased CFTR conductance	Reduced CTFR synthesis	Decreased CFTR stability
CFTR protein
Membrane location	No	Very low	Present	Present	Reduced	Reduced
Outcome	No	Poor	Poor	Partly	Good	Good
Therapeutic proposals	Read-through agents	Correctors+Potentiators	Potentiators	Correctors Potentiators	Stabilizers Amplifiers	Stabilizers Stabilizers
Licensed drugs		Lumacaftor/ivacaftor F508del	Ivacaftor	Ivacaftor R117H
Clinical conditions	More severe diseases			Less severe diseases

Clinical features associated with the mutations and corrective therapeutic approaches.