PULMONARY FIBROSIS.

Cystic Fibrosis and Preimplantation Genetic Diagnosis (PGD)

Fibrosis

If you have a child or family member with cystic fibrosis (CF) or if you and your partner are both CF carriers, you may have wondered about options available to help you have children without this condition. Cystic fibrosis, a condition with childhood onset of serious lung disease and digestive problems, is inherited in an autosomal recessive manner. This means that couples in which both members are CF carriers have a 25%, or 1 in 4, chance with each pregnancy to have a child who inherits two copies of the CF mutation - one from each parent - and will develop the disease.

Couples may learn of their risk to have children with cystic fibrosis because of:

Personal History: One member of the couple has CF and the other has been found to be a carrier.
Family History: A previous child or other family member has CF.
Genetic Carrier Testing: Both members of the couple are found to carry mutations within the gene that causes CF during routine genetic carrier testing.

When a couple wishing to be parents learns they are at increased risk to have a child with a specific inherited condition and they want to reduce the chances of passing this condition on to their children, the following options may be considered:

Natural conception with the 25% chance that the baby will have CF
Natural conception with the option of prenatal diagnosis to confirm fetal status for the genetic condition
Adoption
Use of a sperm or egg donor without a CF mutation to prevent passing on the disorder
Preimplantation Genetic Diagnosis (PGD) with in vitro fertilization (IVF)

Traditionally, couples at risk to have children with CF have either chosen to take their chances through natural pregnancy or have chosen adoption. Another option available since the late 1980s is to conceive naturally and then undergo prenatal diagnosis during the pregnancy to confirm that the fetus does not have cystic fibrosis. However, if the fetus is found to have the condition nothing can be done to change the diagnosis. Some couples prefer other options so they're not faced with the possibility of difficult news during pregnancy. For some couples, using either a sperm or egg donor who is not a CF carrier is an effective way to have a child without CF. For couples that are searching for other ways to have biological children, Preimplantation Genetic Diagnosis (PGD) may be a good choice.

Preimplantation Genetic Diagnosis, or PGD, is a specialized laboratory test used during in vitro fertilization (IVF). PGD allows people who are affected with or are carriers of a specific inherited disorder the chance of having children free of that particular genetic condition.

PGD is an option for couples who are at risk for having children with cystic fibrosis when both members of the couple have had genetic testing and the responsible gene mutations have been identified. PGD is always done in conjunction with in vitro fertilization - a procedure in which the woman's eggs are stimulated to develop, then removed and fertilized by the man's sperm outside the body. When the embryos reach a certain size, one or more cells are removed and tested in a PGD lab for the mutation(s) present in the family. Once the gene mutation status of each embryo is determined, the parents and their IVF doctor then decide which embryos they wish to transfer to the woman's uterus.

PGD has been used by couples at risk to have children with specific genetic diseases for almost 20 years. There are a number of PGD laboratories nationwide that currently offer testing for many different single gene disorders. Most PGD labs can also develop 'custom' PGD tests for families with rare genetic conditions or mutations. Recently, newer PGD methods have allowed testing for chromosome abnormalities at the same time as testing for a single gene disorder such as CF. When couples transfer embryos with normal chromosome results on PGD, the implantation rates may be higher and the miscarriage rates may be lower than with traditional PGD methods that test only for the single gene disorder without evaluating the chromosome number.

Couples who want more information about this option for family planning and details about newer methods of PGD can visit PGD and Cystic Fibrosis at Gene Security Network or call 1-877-GSN-4PGD.