The presence of a nonsense mutation leads to the rapid degradation of the carrier mRNA mutation by a mechanism called NMD (nonsense-mediated mRNA decay) [6, 13]. There are currently 3 main strategies at least for correcting nonsense mutations: exon skipping, inhibition of NMD and nonsense mutation readthrough.

In the laboratory, we developed a strategy for correcting nonsense mutations combining inhibition of NMD and activation of translecture. For this purpose, we have constructed screening systems to identify NMD-inhibiting and/or readthrough enhancers. The molecules thus identified are then tested on cell lines and in murine models carrying a nonsense mutation.

One of our goals is to select a set of molecules that can correct effectively nonsense mutations. For this we have to test these molecules on a great diversity of nonsense mutations.

This work will:

• determine if we can correct all the nonsense mutations tested with at least one of our molecules
• determine what is common within a group of mutations corrected by a given molecule
• be able to assign the parameters that make one mutation is corrected by one molecule and not or little by another.

This study will therefore improve our theoretical knowledge on the recognition of premature stop codons but also to propose therapeutic approaches for the correction of nonsense mutations of the CFTR gene in cystic fibrosis in a targeted way for a patient.

Inclusion Criteria:

• Male / female adults and minors aged 8 years and over
• Patients with cystic fibrosis and carry a nonsense mutation on the 2 alleles of the gene coding for the CFTR channel.
• Patients whose genotype of patients concerning the CFTR gene is known.
• Patients with social security
• Major patients who have given their consent
• Minor patients with parental authorization

Exclusion Criteria:

• Patients who have a mutation other than nonsense in the CFTR gene
• Patients whose CFTR gene was not sequenced on the 2 alleles
• Patients not wishing to participate in this study or persons not giving or not able to give consent.
• Pregnant or lactating women
• Patients under curatorship or guardianship

Patients with cystic fibrosis and carry a nonsense mutation on the 2 alleles of the gene coding for the CFTR channel.