Table 3.

CFTR Mutations and Modulator Therapies.

Mutation Class (more severe to less severe)	Impact on CFTR	CFTR Modulator Therapy	Example of CFTR Modulator
I	Defect in CFTR protein production
II (example Phe508del)	Ineffective CFTR protein processing → ineffective trafficking to cell surface	Corrector +/- potentiator	Ivacaftor/lumacaftor Tezacaftor/ivacaftor Elexacaftor/tezacaftor/ivacaftor
III (example G551D)	Inability of CFTR protein to remain open “gating mutations”	Potentiator	Ivacaftor
IV	Ineffective CFTR protein with reduced chloride transport	Potentiator	Ivacaftor
V	Decreased CFTR synthesis
VI	Reduced CFTR stability