What is a genetic disorder and what part does genetic screening play in helping families to deal with the risk or reality in their children?



Recessive genetic disorders are when both parents carry a diseased gene but do not suffer from the disease themselves. They are called 'carriers'. Their children must inherit the diseased gene from BOTH parents to develop the disorder.

If the child inherits only one gene they will also become carriers, but not suffer from the disease. It is also possible that they will not inherit the gene at all. In each case, the likelihood of having a child develop the disorder goes up with each pregnancy. It is simply a matter of chance.

Genetic Screening of Parents

Screening a couple BEFORE pregnancy can identify the risks for potential recessive disease where both parents carry the same recessive gene. Once a gene (such as Tay-Sachs) is found in both individuals, the couple can be informed on the risks of passing the gene on and the likelihood of their children developing the disorder.

Having this knowledge not only prepares couples for the possible outcome in a pregnancy but also permits them to decide whether getting pregnant is worth the risk.

Genetic Screening During Pregnancy

Genetic screening during pregnancy is subject to the most controversy. While the testing is not done entirely for genetic disorders (spina bifida and Downs syndrome being two that are NOT inherited gene disorders) the facts still remain that screening during pregnancy has its pros and cons.

While genetic screening may prepare a family for the risk of disease and provide time for genetic counseling for the parents, usually there is nothing that can be done for the baby during the pregnancy.

The fact that most tests cannot guarantee the health of the child and that false positive tests may lead to undue anxiety and possibly to the termination of a healthy pregnancy are also dangers that must be acknowledged. Some tests, such as the amniocentesis, also carry a risk themselves (although a small one). Parents should discuss this with their health care provider.

More recently it is the possibility that genetic testing may lead to more advanced measures of choosing the 'right' baby that has caused a stir. Each parent must weigh the risks and benefits of these tests.

Genetic Screening of Newborns

Genetic screening of newborns has become standard practice in countries like the US and Canada.

By taking a small sample of blood from a pin prick in the newborn's heel, the sample is then analyzed for genetic disorders. Some of these disorders, when caught early on can be treated (such as sickle cell anemia) and some even eliminated. This precaution has saved many children a lifetime of suffering from a debilitating disease.

The advancement of science continues to amaze and alarm us with what is possible. While many individuals will benefit from the assistance of screening the controversy regarding how far science should intrude is sure to continue.