WHAT IS CYSTIC FIBROSIS?

Cystic Fibrosis (CF) is a genetic condition that a child can only be born with if BOTH parents carry the defective gene. 1 in 25 people in New Zealand carry the gene that causes CF, making it New Zealand most common life threatening genetic condition.

CF has devastating effects on people born with it; the condition affects a large number of body organs and functions but manifests particularly in the lungs, leading to progressive and irreversible lung damage. Sadly there is no known cure and people with CF have an average life expectancy of only 29 years here in New Zealand.

WHAT IS BREATH4CF?	ˆ TOP

Breath4CF was established within the Cystic Fibrosis Association of NZ, after discussions with medical specialists who unanimously agreed that (aside from medications) physical exercise is the best way for a person with CF to preserve their own quality of life, lung function and longevity. However it was identified that families affected by CF struggle to meet the cost of these extras as well the ongoing medical and nutritional costs of this condition. Therefore under the Breath4CF grant fund, financial assistance is given to people with CF so that there is no barrier to participating in life preserving exercise or activity. Assistance is by way of gym memberships, entry fees, lessons, sports equipment etc in fact Breath4CF will help towards any physical activity, for a person with CF, that would produce a health benefit.

It is Breath4CF's stated vision that all people with Cystic Fibrosis participate in physical activity as part of their daily life and that the cost of such activity is not a barrier to participation.

HOW DOES CF AFFECT CHILDREN?	ˆ TOP

Normally the mucus in our bodies is thin and slippery and works as a lubricant. In CF, however, the mucus lacks the right amount of water making it very thick and stocky. This gluggy mucous blocks the tiny tubes and ducts of various organs. Recurrent respiratory infections, caused by blocked bronchial tubes cause shortness of breath and a chronic cough, reoccurring infection and permanent scarring leading to progressive lung disease. Also in approximately 90 per cent of patients the ducts in the pancreas are blocked, and so digestive enzymes produced by the pancreas are unable to flow into the digestive tract. This leads to malabsorption issues and chronic malnutrition.

ARE ALL CHILDREN SIMILARLY AFFECTED?	ˆ TOP

No, there is a great variation in the effects of Cystic Fibrosis. A few children have adequate digestive juices to digest normal food, but most have to take a special enzyme preparation to aid their digestion. Some children have a persistent cough while others suffer from very few chest infections. Even in one family, one affected child can be troubled much more than another. The reason for this variability is another unknown factor about the condition. Sometimes it is possible to trace the variability in the features of Cystic Fibrosis to the type of mutation causing the disease. A small number of mutations are known to be associated with nearly normal pancreatic function. Sometimes these people also seem to have milder chest disease. Conversely some children have a severe case causing rapid decline.

WHY IS IT CALLED CYSTIC FIBROSIS?	ˆ TOP

When the condition was first discovered, it was thought that the main effect was on the pancreas, an organ in the body which produces digestive juices. The pancreas in children with Cystic Fibrosis contains cysts and increased fibrous tissue, hence the term Cystic Fibrosis of the pancreas. It is now realized that the effects on the pancreas are only one aspect of the condition which is commonly termed Cystic Fibrosis or CF.

HOW IS CYSTIC FIBROSIS DIAGNOSED?	ˆ TOP

In New Zealand the National Testing Laboratory has been screening all new-born infants for Cystic Fibrosis since mid-1981. It measures the amount of pancreatic enzymes in a baby's blood. This is conveniently done by using the blood spot sample which is routinely taken on all babies on the fifth day of life, and which is used to check for other diseases. This measurement of pancreatic enzyme levels is not a definitive diagnosis, but 'screens' out the babies that are likely to have Cystic Fibrosis. If the level is abnormal another sample from the same blood card will be used to test for the four or five most common mutations causing Cystic Fibrosis in New Zealand. All these babies will then be clinically assessed and have diagnostic tests which will include a sweat test. A blood sample will be taken for a diagnostic mutation analysis. A test for pancreatic insufficiency will also usually be performed. The sweat test involves stimulating a small area of the skin to produce sweat, which is analysed for sodium and chloride (common salt). In
Cystic Fibrosis there is an excessive concentration of salt in the sweat. The sweat test will usually be performed at least twice, and now with the ability to screen for several of the more common CF mutations, it is possible to determine on most occasions that a child does or does not have Cystic Fibrosis. However in about 1-2 percent of cases it is still difficult to be absolutely sure based on these tests alone.

Besides new-born screening, other factors which may lead to further investigation are symptoms of pneumonia, or malabsorption, meconium ileus (obstruction of the bowel in the new-born) and an older brother or sister with the disease.

IS CYSTIC FIBROSIS INHERITED?	ˆ TOP

Yes, it is inherited - that is, it is passed from the parents to the child. Many of our body features, such as hair colour, colour of our eyes, our height, are inherited, or in other words they are determined by genes passed from the mother and father in the egg and sperm respectively. We all have many millions of genes which are very small particles in the body cells which carry all the information about inherited features. All genes come in pairs, one inherited from each parent. Thus we have a pair associated with the colour of our eyes, another with hair colour. Both parents of a child with Cystic Fibrosis have an abnormal gene in one of their gene pairs. The parents are called carriers of the genes. This single abnormal gene does not cause them any ill effect. If two carriers procreate, they may pass their abnormal genes on to their children. If each parent passes on the abnormal gene, the child will have two abnormal genes and so have Cystic Fibrosis. There is a one-in-four chance of this occurring. There are two chances in four that the child will receive one abnormal gene and so will be a carrier like the parents. There is also another one-in-four chance that neither parent will pass the abnormal gene to the child and so the child will neither have nor be a carrier of Cystic Fibrosis. These chances apply to each pregnancy, so having an affected child does not alter the risk for the next. The incidence is exactly the same for girls and boys.

The most common mutation causing Cystic Fibrosis is called dF508, and it accounts for between 50-80 percent of all cases of the disease. However researchers have now identified more than 600 other mutations in the CF gene responsible for the disease. Most individuals with Cystic Fibrosis in New Zealand have at least one copy of the dF508 mutation.

HOW COMMON IS CYSTIC FIBROSIS?	ˆ TOP

Cystic Fibrosis occurs in peoples of Caucasian origin, but it is rare in Africans, Asians and Polynesians. In New Zealand, it is estimated that about 1 in 25 of the Caucasian population will be a carrier of the abnormal gene, and therefore about 1 in 625 marriages will be between two Cystic Fibrosis carriers. Of all births in New Zealand, 1 in 3000 to 1 in 3,500 infants born will have Cystic Fibrosis. Currently there are more than 450 children and adults with Cystic Fibrosis in New Zealand.

CAN CARRIERS BE IDENTIFIED?	ˆ TOP

Carriers have no features of Cystic Fibrosis and are usually healthy individuals. Being a parent of a child with Cystic Fibrosis was the usual way that carriers of the abnormal CF gene were identified. It is now possible to test for carriers of Cystic Fibrosis. This is particularly advised for close relatives in a family where a person with Cystic Fibrosis has already been identified. In New Zealand genetic services are limited, and are based in large hospitals (see neonatal diagnosis). They or your paediatrician can, however, arrange for the necessary blood tests to be performed.