Table 1 Summary of different classes of CFTR mutations
From: Targeted therapies to improve CFTR function in cystic fibrosis
Mutation class | Nature of defect | Functional consequence | Example | Therapeutic strategy |
|---|---|---|---|---|
I | CFTR protein synthesis | Reduced CFTR protein expression | Gly542X | Production correctors (ataluren) |
II | CFTR protein processing | Misfolded CFTR not transported to cell surface | Phe508del | Corrector plus potentiator (lumacaftor plus ivacaftor, VX-661 plus ivacaftor) |
III | CFTR channel gating | Reduced/lack of CFTR channel opening | Gly551Asp | Potentiator (ivacaftor) |
IV | CFTR channel conductance | Misshaped CFTR pore restricts Cl− movement | Arg117His | Potentiator (ivacaftor) |
V | Reduced CFTR protein production | Very low levels of CFTR protein | 3849 + 10 kb C → T | No data available |
VI | High CFTR protein turnover at cell surface | Functional but unstable CFTR protein at cell surface | 120del23 | No data available |