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.ong-term issues include difficulty breathing and coughing up sputum as a result of frequent lung infections. Other symptoms include sinus infections, poor growth, fatty stool, clubbing of the finger and toes, and infertility in males among others.