What is cystic fibrosis?
Cystic fibrosis (CF) is a genetic disease that affect the respiratory (breathing) and gastrointetinal (digestive) system. In CF, the inner space of organs is frequently clogged up by thick secretions (mucous).
In Greece, almost 1 child every week is born with CF. Approximately 1 in 20 to 25 people is a carrier of a faulty gene (that means that almost 500, 000 Greeks are carriers of CF).
What causes cystic fibrosis?
Cystic fibrosis is caused when a gene, called CFTR, is mutated. A mutation is a condition where the genetic information of our cells becomes abnormal kai one or more body functions stops been performed the usual way. The commonest mutation is called f508del or ΔF508 and appears in 70% of the cases in North America. In Greece, the respective percentage is between 50- 55%. Until today, more than 2000 different mutations have been discovered, all of them causing CF.
The CFTR gene normally produces a protein that regulates the amounts of cellular salts (sodium and pottasium). If this gene becomes mutated, this results to the production of thick mucous that cloggs up cavities and tubes in our boody. These blockages eventually destroy lungs, intestines (gut) and other organs, leading to CF symptoms.
How is cystic fibrosis inherited?
Each one of us carries in his/ her genetic material (DNA) two copies of the CFTR gene. Patients of CF, carry since birth two abnormal copies of the CF gene, having inherited each one from both their parents. People carrying only one abnormal copy are called carriers and are disease- free. So, in order for a child to be born with CF, both his parents have to be either carriers or having the diasease.
The most common scenario is that where both parents are carriers of one abnormal CFTR gene. They are completely healthy and they are unaware of their gene status. In that case, for each baby born from this couple, there is a 25% chance that the baby is affected by CF. There is also 50% chance that their baby is just a carrier and, thus, healthy and another 25% that the baby carries both normal copies of the gene.
What are the cystic fibrosis symptoms?
The cystic fibrosis symptoms usually appear in early childhood and include:
- persistent cough
- frequent chest infections
- slow body weight growth
One of the early symptoms of CF is that your child's sweat is unusually salty, something that can be detected when kissing it.
Can cystic fibrosis be detected before birth?
Antenatal (before birth) detection of CF is feasible. It is useful in cases where both parents have been identified to carry the abnormal gene(s). Additionaly, antenatal detection of CF is useful when the couple already has an affected child but the underlying mutations have not been identified. In order to diagnose CF antenatally, both parents have to be tested. In order to make a diagnosis in the unborn baby, an amniocentesis or placenta sampling (CVS) after 11 weeks of pregnancy is warranted.
Testing the parents is done either with a blood or saliva test. Parents are tested against the commonest CFTR gene mutations. If both parents carry the same gene mutation, then testing the baby against CF is indicated.