Cystic fibrosis, known as CF for short, is a single gene disorder caused by a deletion of three nucleotides in a gene called CFTR. The disease causes thick mucus to accumulate in many parts of the body, especially the lungs, and typically leads to early death due to respiratory problems.
Cystic fibrosis is an autosomal recessive disorder, meaning that it manifests itself as a mutation creating a recessive allele on an autosome (the CTFR gene is found on human chromosome 7). Accordingly, both males and females can act as carriers for the condition (and prospective parents are encouraged to get simple testing for this recessive allele).
Below is shown the location of the CFTR gene on human chromosome 7 (highlighted in red).