Cystic fibrosis: Causes, symptoms, diagnosis, treatment
Cystic fibrosis, sometimes referred to as CF, is an inherited condition causing the lungs and digestive system to get clogged up with sticky, thick mucus. Cystic fibrosis can be life threatening.
The condition affects more than 10,000 people in the UK.
There is no cure for cystic fibrosis, but treatment can help ease symptoms and help prevent complications.
All babies are screened for CF soon after they are born with a tiny amount of blood taken with a heel prick.
What causes cystic fibrosis?
Cystic fibrosis occurs in children who have inherited two abnormal copies of a specific gene, one from each parent. A parent who does not have CF but has one normal copy of this gene and one abnormal copy is called a CF carrier. The normal copy dominates, so the parent shows no sign of CF. In some cases, carriers pass on their normal gene to their child. In other instances, they pass on their abnormal copy. A child who receives a normal copy from one parent and an abnormal copy from the other will be a CF carrier and won't have the disease. A child who receives an abnormal gene from both parents will develop CF.
When both parents carry one abnormal copy of the gene, each child they produce has a 25% chance of inheriting two abnormal copies and having the disease, a 25% chance of inheriting two normal copies, and a 50% chance of inheriting one abnormal copy and one normal copy - causing them to be a carrier.
If only one parent has an abnormal gene and the other parent has two normal genes, there is a 50% chance that each child will be a carrier, but it's impossible for any of these children to have the actual disease.
If one parent has CF and the other parent is a carrier, each child has a 50% chance of inheriting the disease and a 50% chance of being a carrier. If one parent has CF and the other has two normal copies of the gene, the child will be a carrier. Because of the reproductive problems associated with CF, it is highly unlikely a child would be born to two parents with the disease. However, all children born to such a couple would have a 100% chance of inheriting CF.
Males and females are equally likely to inherit the disease.
What are the symptoms of cystic fibrosis?
The symptoms of cystic fibrosis vary. While some children may exhibit symptoms at birth, others may not develop symptoms for weeks, months, or even years. The severity of symptoms also varies, with some children showing only mild digestive and respiratory problems and others displaying severe food-absorption problems and life-threatening respiratory complications.
The most common symptoms of cystic fibrosis are:
- Salty-tasting skin, which parents note when they kiss an affected infant, for example
- Persistent coughing, wheezing, or bouts of pneumonia or sinusitis
- Progressive difficulty breathing
- Excessive appetite but poor weight gain
- Bulky, smelly, greasy bowel movements