Another example is the option to screen for a disease called cystic fibrosis. This is one of the most common genetic conditions that can affect newborns, and it affects people of all ethnicities. This is a disease of the lung and intestines that can lead to recurrent problems such as pneumonias that over time can be lethal.
It is possible to detect the majority of this type of chromosomal abnormality (is autosomal recessive conditions) by performing blood work from the parents. For a baby to get a disease such as cystic fibrosis, both parents need to be a carrier for the disease.
When a parent is a carrier it means that they have only one copy of an abnormal gene and thus don't have the disease themselves. However, when both parents are a carrier, there is a 25% chance for the baby to get two copies of the abnormal gene, which is required to contract the disease.
Until recently, cystic fibrosis was the only disease that the American College of Obstetrics and Gynecology recommended discussing/offering patients. The American College of Medical Geneticists has recommended more tests to be offered.
Several genetic testing companies have developed extensive screening mechanisms for hundreds of different diseases.
Were both parents found to be carriers for any one of these diseases, there is a 25% chance that the child will be affected. Fortunately, if this were to be the case, a couple could decide to do in vitro fertilization and perform PGD on embryos created in the laboratory. These biopsies would then be analyzed for the disease, and only those embryos free of the chromosomal defect would be chosen for transfer into the uterus.
Certain birth defects such as those of the heart and other psychiatric conditions, such as manic-depressive disorder and schizophrenia, have a hereditary tendency. Patients may decide to receive formal genetic counseling to receive an accurate appraisal of the risk of passing these problems genetically from the parent to the child.
While it is impossible to guarantee a completely normal child 100% of the time (major and minor defects can occur in a approximately 5% of all deliveries), attention to these details and a discussion with providers prior to or in early pregnancy may improve the opportunity to deliver a healthy baby.