Cystic fibrosis is a recessive genetic disorder caused by mutations in the cystic fibrosis transmembrane conductance regulator gene. There is a broad range of the age for the onset of cystic fibrosis. Cystic fibrosis is considered a monogenic disorder. Monogenic means inherited conditions that arise from mutations on a single gene. The picture shown above there are likely major contributions from the non-CFTR gene as well as environmental influences. Cystic fibrosis is one of the most common autosomal recessive disorders for Caucasians and the median age of survival is 39.