Cystic Fibrosis Screening: ALL Donors Screened for 86 mutations

Background 


Fairfax Cryobank continually strives to be the industry leader in genetic and infectious disease testing. We were the first Cryobank to provide genetic screening of all donors for Cystic Fibrosis (CF) starting in 1990. Cystic fibrosis (CF) is the most common severe inherited disease in Caucasians. It is less frequent in individuals of Black or Asian ancestry. The disease usually begins in infancy or childhood with recurrent lung problems (including pneumonia), intestinal difficulties, or poor growth. Medications, frequent visits to physicians, and hospitalizations are almost always required. While there has been much improvement in the care of children with CF, many of them still die in early childhood, and about half of all individuals with CF die before they reach age 30. Over 1000 different CF mutations within the CF gene have been identified to date. The most common, called Delta F508, accounts for 70% of all CF mutations, while many others have been seen in only a single family.

The American College of Medical Genetics (ACMG) in association with the American College of Gynecology and Obstetrics (ACOG) issued a position statement during 2001 stating that all Caucasian couples seeking pregnancy should be offered Cystic Fibrosis screening.

Just as Fairfax Cryobank was the first to screen ALL donors for Cystic Fibrosis back in 1990, Fairfax Cryobank is now the first to retroactively screen ALL donors on our register for 86 CF mutations.This means that every donor on our current donor register has been screened for at least 86 CF mutations.

Starting in January 2017, all new donors are being screened for cystic fibrosis by gene sequencing, and if negative, it reduces the risk that they are carriers even further. See information about our Expanded Genetic Disease Testing All new donors starting in 2018 are being tested for 280+ diseases by gene sequencing, including CF.

The risk of a Caucasian individual carrying a CF mutation is 1 in 29, and no screening currently available can eliminate all carriers from the population. Screening donors for 86 mutations lowers the risk even further. The risk that a Fairfax Cryobank semen donor who tests negative is a carrier of Cystic Fibrosis is no greater than 1 in 325.

 

Inheritance and Risks 


All couples have some risk of having a child with CF. Genes are passed to your child in the egg and sperm. Ordinarily you have two normal copies of a gene. If one copy of the CF gene is abnormal, you are still healthy, but are a carrier of CF. If you and your partner are both carriers, you have a 1 in 4 chance that your baby will inherit two CF genes and be affected with CF. If this happens your child will have Cystic Fibrosis. Like most individuals, you may not realize that you may be at risk for having a child with the disease. Most CF carriers have no family history of affected family members. Approximately 1 in 29 Caucasian Americans are carriers of the CF gene. One in every 3,360 Caucasian births results in a child who is affected with Cystic Fibrosis. Individuals whose ancestors are African, Hispanic or Asian can also be affected with CF, but this occurs less often. For example, in the African American population, only one out of every 17,000 births result in a child who is affected with CF.

 

Screening 


Fairfax Cryobank screens all prospective donors for Cystic Fibrosis (1) by obtaining a detailed family medical history and (2) by performing genetic screening on a sample of the donor's blood. The specialized testing is performed by a fully licensed/accredited genetics laboratory. A positive test diagnoses that you are a carrier, while a negative test greatly reduces, but does not eliminate, the risk of being a carrier.

At the present time, over 1000 different genetic changes (known as mutations) in the CF gene have been identified. Only one mutation is necessary to change a normal gene into a CF gene. At the present time Cystic Fibrosis carrier screening cannot provide 100% certainty that an individual is not a carrier of a CF mutation. DNA studies do not constitute a definitive diagnostic test or precise carrier test for CF in all families. Thus the interpretation of all data is usually given as a probability of being a carrier.

Read more about our Expanded Genetic Disease Testing. All new donors are being tested for 280+ diseases by gene sequencing, including CF.