How Does Heredity Effect Your Unborn Baby?
Mapping out Your Family Tree
Deciphering Your Genetic Information
It is sometimes hard to distinguish between medical information and determine which elements have genetic implications. If you are uncertain about a condition, contact a clinical geneticist to help you determine whether or not further attention is necessary. The key information you need concerns issues that can affect your personal health as well as the risk of having a child with a birth defect or genetic disorder.
Here are just some examples of situations in which you may want to consult with a specialist:
- If a close relative has had three early miscarriages, it raises questions about a chromosome abnormality. A couple, while each healthy, who have had three or more miscarriages, should each have a chromosome analysis to exclude the possibility that one of them carries a chromosome defect (which might also be carried within the family.) After three losses, there is between a three and an eight percent chance that one member of this couple carries a chromosomal abnormality. This analysis would enable a doctor to determine any future risk for having an affected child and undertake the necessary prenatal genetic studies around 15 or 16 weeks in a future pregnancy.
- A history of an unexplained stillbirth in your family also raises questions, not only about chromosome defects, but also about some biochemical genetic diseases and even about a mother’s health. A history of a near relative with a birth defect (such as Spina Bifida or Down Syndrome) strongly indicates that a couple should determine their own risks through genetic counseling from a board-certified clinical geneticist.
- A history of mental retardation, especially in males on the mother’s side of the family, raises questions about sex-linked genetic disorders transmitted through females to half their male offspring. There are scores of disorders characterized by mental retardation with this mode of inheritance. A history of unexplained mental retardation on either side of the family should never be ignored.
Sometimes, a number of very different and seemingly unrelated types of birth defects can occur on one side of the family affecting different members. For example, a sister may have been born with a cleft lip and palate, an aunt has mental illness (psychosis), and two first cousins have speech and learning problems, both having been born with heart defects. While these various defects appear unrelated, they may not be, and do raise questions about a condition called Velocardiofacial Syndrome, which is not rare. Very specific genetic tests are now available to diagnose this genetic disorder and prenatal diagnosis is also possible.
- Any individual with a family member who has had deep vein thrombosis (blood clots in veins of the leg most commonly) or pulmonary embolism (a clot that breaks off and travels to the lung where it can cause acute shortness of breath and even death) needs to consult their physician and request DNA testing for the Factor V Leiden and Prothrombin gene mutations. Defects in either one or both of these genes predispose an individual to thrombosis mainly within veins, but treatment is available. Moreover, for an affected woman, pregnancy loss occurs three times more often than normal and there is also an increased frequency of toxemia later in pregnancy.
Among the many other medical disorders to be inquired about are those that involve heart and blood vessel disease, brain and nervous system disorders, and diseases of the muscles. There are no disorders, which do not have a genetic component, or are not directly caused by harmful genes. Only by being alert to your family history can you diminish the risks we all take in our efforts to have the healthiest baby we can.
You can call the American College of Medical Genetics (301-571-7127) for help in identifying the nearest Board-certified specialist.
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