By Andrea Rodrigo BSc, MSc (embryologist).
Last Update: 03/11/2016

Cystic fibrosis (CF) is a genetic-based disease affecting mostly the lungs, although it may also have a negative impact on the pancreas, liver, or intestine. Long-term complications derived from CF include coughing up mucus in lungs and the digestive tube. It may develop in other body areas as well, although to a lesser extent.

It stands for one of the most common chronic lung diseases among children and youth. It is considered to be a serious condition, since it may lead to the death of the affected person. In fact, patients usually pass away due to lung infections caused by pseudomonas or staphylococcus (a.k.a. staph infection).

According to the Spanish Cystic Fibrosis Federation, one case of cystic fibrosis occurs per 5,000 live births and one person every 35 inhabitants is a healthy carrier of CF.


Cystic fibrosis is a hereditary condition that follows an autosomal recessive pattern of inheritance. A mutation or birth defect in the CFTR gene, located on the long arm of the 7 chromosome (7q31.2), leads to failure in the cell transport mechanism and also when it comes to locating the protein expressing such gene, which in fact has the same name, i.e. CFTR protein. This genetic disease causes the build-up of a thicker, more sticky fluid than normal, which is called mucus.

The mucus secreted builds up in the airways, the lungs, and the pancreas, hindering therefore the right working of these organs and giving rise to life-threatening lung infections and severe digestive system problems.


Even though there are many people who are carriers of the CFTR gene, they never express or develop none of the common symptoms associated with this disease. This happens because, for the disease to develop, the affected person must have developed both defective genes, that is, one from the father and another one from the mother, since it is an autosomal recessive genetic disorder.

A person who develops a normal gene along with abnormal recessive one will be a carrier of cystic fibrosis. By carrier we mean a person who could pass it to offspring despite CF never develops on him/her.

Main symptoms linked to cystic fibrosis are:

  • Symptoms in newborns: it mainly causes stunted growth, failure to gain weight, and salty-tasting skin.
  • Bowel function: abdominal pain, severe constipation, increased flatulence, pale-colored stools with a foul odor, and weight loss.
  • Lungs: cough, increased mucus secretion, fatigue, stuffy nose, nasal polyps, pneumonia, sinus pain or pressure, etc.

People who suffer from cystic fibrosis may also develop inflammation of the pancreas, respiratory symptoms, clubbing in the fingers, and male infertility in the case of men.


The majority of children who suffer from cystic fibrosis have it diagnosed by the time they are two years old. For a small percentage of youth, this disease remains undetectable until they are 18 years old or more. The latter group usually develop cystic fibrosis in a milder form.

Early diagnosis is essential in providing a proper treatment schedule that improves the patient’s life span and quality of life. The provision of special care is crucial as well, ideally in CF care centers.

The treatment of cystic fibrosis involves the following steps:

  • Proper nutrition
  • Medicines for cystic fibrosis to fight against infections and inflammations originated in the airways (e.g. antibiotics, expectorants, etc.)
  • Physical therapy (chest physiotherapy, thoracic spine mobility exercises to prevent malformations, and exercise).

In the advanced stage of the illness, patients could face the possibility of a lung and/or liver transplant.

Preventing the transmission of CF

Both those suffering from CF and those who are carriers of the CFTR gene may pass the gene mutation that causes cystic fibrosis to offspring. Given its autosomal recessive pattern of inheritance, chances for your child to develop it if both parents are carriers for CF reach 25%, whereas there is a 50/50 chance that the child is a carrier, and just a 25% chance of being totally healthy.

Preimplantation genetic diagnosis (PGD) may help avoiding the birth of children with this degenerative disorder. It is a cutting-edge assisted reproductive technology (ART) that allows the performance of a genetic analysis on day 3 of embryo development.

This way, only healthy, mutation-free embryos are selected for carrying out the embryo transfer. In case the genetic analysis shows embryos carrying some kind of genetic abnormality, such as the cystic fibrosis gene, they will be automatically ruled out for being transferred to the maternal uterus.

Thanks to PGD, patients who are carriers or suffer from cystic fibrosis can have healthy offspring. PGD is an additional technique that can be performed regardless of the chosen assisted reproductive technology. All in all, it represents an advance when it comes to the prevention of genetic diseases.

Authors and contributors

 Andrea Rodrigo
BSc, MSc
Bachelor's Degree in Biotechnology from the Polytechnic University of Valencia. Master's Degree in Biotechnology of Human Assisted Reproduction from the University of Valencia along with the Valencian Infertility Institute (IVI). Postgraduate course in Medical Genetics. More information

One comment

    1. Kathy Louise

      Hello, my first son has Cystic fibrosis and we are looking to see about having more kids, but need to turn to PGD and IVF to do so. I’m from the UK but wish to know if someone has done it abroad. If so, which fertility clinic are good or recommended? Also, if anyone in the UK has done it in a really good clinic, I hear your options too.

      We really need to get information ASAP, so we can get moving and hopefully have more children free from this disease… Thanks!!