Previously, we synthesized CLK inhibitors10 and demonstrated their therapeutic potential in disease models of cystic fibrosis (c.3849 + 10 kb C > T mutation of cystic fibrosis transmembrane conductance regulator (CFTR))11, Duchenne muscular dystrophy (c.4303 G > T mutation of dystrophin)12, and anhidrotic ectodermal dysplasia with immunodeficiency (EDA-ID; IVS6 + 866 C > T mutation of NF-kappa-B essential modulator (NEMO))13. Here, CFTR is linked to immunodeficiency disease.