What is being tested?The CF gene mutation test identifies
mutations in the CFTR
gene. Each cell in the human body (except sperm and eggs) has 46
chromosomes (23 inherited from the mother and 23 from the father). Genes on these chromosomes form the body's blueprint for producing
proteins that control body functions.
Cystic fibrosis is caused by a mutation in a pair of genes located on chromosomes 7. Both copies (alleles) of this gene must be abnormal to cause CF. If only one copy of the gene pair is mutated, the patient will be a
carrier. Carriers are not ill, they do not have any symptoms, but they can pass their abnormal CF gene copy on to their children.
To date, almost 1000 different mutations of the chromosome 7 gene have been identified, but only a few of the mutations are common. The majority of CF in the UK is caused by a mutation called deltaF508.
When CF gene mutation testing is done, the laboratory specifically examines the CFTR gene on each chromosome 7 for a number of mutations. If the initial panel of mutations demonstrates a mutation, additional testing for other mutations may be indicated if the individual is suspected of having the disease.
