Therefore, evidence from longitudinal studies in larger cohorts, including patients with CF who are F/F, as well as patients with CFTR gating and residual function variants treated with different CFTR modulator therapies, is needed to further understand the relationship between the extent of functional rescue of CFTR protein and clinical response, including the long-term impact on disease progression and survival. The gene discussed is CFTR; the disease is cystic fibrosis.