There is a 1 in 25 chance of someone being a carrier of the CF gene. (uk statistics).
If you look at the full CF gene being part of a puzzle, there are 2 pieces to the puzzle. 1 piece is from each parent.
A carrier of CF has a healthy gene from one parent and a faulty gene from the second parent. A person with CF has a faulty gene from each parent.
IF one parent is a carrier and the other parent is not, then their child won't have CF, but there is a 50-50 chance their child could be a carrier.
IF both parents are carriers, then there is a 1 in 4 chance their child could have CF.
Hope this helps, tried to break it down as much as I can.
Moderator of the Cystic Fibrosis forum
Hey, I'm Gem with CF, age 29 and diagnosed at 2 years old. I'm no expert but having CF myself I've learnt a few things along the way.
Diagnosed with: Cystic Fibrosis, Asthma, ABPA, Clinical Depression, Mild Liver Cirrohsis, Mild Osteopenia, Erythema Nodosum, Proximal Myositis, Polyarthralgia