LUM: lumacaftor; IVA: ivacaftor; Hbg: hemoglobin; CF: cystic fibrosis; GHD: growth hormone deficiency; GH-IGF-1 axis: growth hormone-insulin-like growth factor-1 axis; CFTR: cystic fibrosis transmembrane conductance regulator. The gene discussed is CFTR; the disease is cystic fibrosis.