Thursday, October 23, 2014
Inherited Disorders and Birth Defects
Carrier Complications for CF
Whilst having counselling by a reproductive medical specialist it was mentioned to me that in rare cases, a carrier for CF (which I am) can experience some medical difficulties. What are these problems?
As you probably know, cystic fibrosis (CF) is a common genetic disease. CF affects the lungs and digestive organs. It is caused by a mutation (change) in a gene called CFTR. When this gene is mutated, it causes the secretions in the lungs and other organs such as the pancreas, bile duct and GI tract to become very thick and sticky. This interferes with breathing and digestion.
The most common mutation seen in CF is called F508 and is found in about 70% of people who are carriers for CF. However, there are over 1500 mutations that have been found in the CFTR gene. Some of these gene changes cause very little problem, others may lead to classical CF. Because CF is an autosomal recessive disease, people who are carriers, (that is - have one normal working copy of the CFTR gene and one that is mutated or non- working) do not have any health problems. However, on rare occasions, someone who is found to have a common mutation (such as F508) may also have a mutation or variant in the CFTR gene on the other chromosome. In this case, that person is not truly a carrier, but has 2 CF mutations, and could develop health problems later in life such as chronic pancreatitis (inflammation of the pancreas) or lung problems such as bronchiectasis (inflammation of the lungs). Also, men with 2 CF mutations who experience infertility problems (but who have no other health problems) may have CBAVD (congenital bilateral absence of the vas deferens – they are missing the tubes that carry the sperm from the testes to the penis).
With all of the changes that have happened in the field of genetics and rapid advances in technology, we are finding that the CFTR gene is very complicated. Geneticists and genetic counselors are happy to discuss the different clinical problems that can occur depending on the specific type of changes that are found in the CFTR gene. If you have not already done so, I would recommend that you talk to a genetic counselor or geneticist about these issues. You can ask your physician for a referral or locate a genetics center near you at the National Society of Genetic Counselors’ Resource Center website.
Anne Matthews, RN, PhD
Associate Professor of Genetics
School of Medicine
Case Western Reserve University