Different people may have different degrees of symptoms. CF is an autosomal recessive disorder. It is caused by the presence of mutations in both copies of the gene for the protein cystic fibrosis transmembrane conductance regulator (CFTR). Those with a single working copy are carriers and otherwise mostly normal.he main signs and symptoms of cystic fibrosis are salty-tasting skin, poor growth, and poor weight gain despite normal food intake, accumulation of thick, sticky mucus, frequent chest infections, and coughing or shortness of breath.