What Causes Cystic Fibrosis?
Cystic fibrosis (CF) is caused by a defect in a gene
called the cystic fibrosis transmembrane conductance regulator (CFTR) gene.
This gene makes a protein that controls the movement of salt and water in and
out of the cells in your body. In people with CF, the gene does not work
effectively. This causes the thick, sticky mucus and very salty sweat that are
the main features of CF.
Each of us inherits two CFTR genes, one from each
parent.
- Children who inherit an abnormal CFTR gene from
each parent will have CF.
- Children who inherit an abnormal CFTR gene from
one parent and a normal CFTR gene from the other parent will not have CF. They
will be CF carriers.
CF carriers:
- Usually have no symptoms of CF
- Live normal lives
- Can pass the abnormal CFTR gene on to their
children
When two CF carriers have a baby, the baby has a:
- One in four chance of inheriting two abnormal
CFTR genes and having CF.
- One in four chance of inheriting two normal CFTR
genes and not having CF or being a carrier.
- Two in four chance of inheriting one normal CFTR
gene and one abnormal CFTR gene. The baby will not have CF but will be a CF
carrier like its parents.
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