|by Donna Przecha|
One of the most important uses of history is to help predict the future and avoid the mistakes of the past. When it comes to medical matters, many people say they would just as soon not know what the future holds. This might have made sense in the past when a person could not do much about his medical future. However, we now have lots of options, and based on what you know of your family's medical history, you may be able to influence your future health.
For example, of my six grandparents and parents, five died of stroke or heart attack. My own cholesterol continued to climb in spite of careful dieting. When I learned that three close relatives also had high readings I realized this was a hereditary problem. Fortunately, we now have medication to help even the poor odds that a bad gene might have given us.
If there is a family history of unusual afflictions even seemingly benign ones or many people dying from similar causes, you would do well to begin investigating. You may find there is simply a predisposition to one disease and there are precautions that can be taken. Or, you might find a genetic disorder that you, your children or grandchildren should seriously investigate before having children.
Some families may be predisposed towards a particular disease. It means they are not born with it, but a large number of people develop it over their lifetime. This information can be helpful to you as you can avoid situations that might bring an early onset of the disease. You can also be vigilant in watching for potential symptoms and getting early treatment. For example, if you know you are predisposed towards diabetes, you can be careful of your diet and make sure you are tested periodically.
Hereditary Genetic Disorders Kings, Queens, and You
There are many diseases themselves not just the predisposition that can be passed on to a child. In addition, because of race, sex or other factors, you may be more likely to have this gene. Many, if not most, of these diseases, such as Tay-Sachs, Cystic Fibrosis, Sickle Cell Anemia and Huntington's Disease, are terrible, debilitating conditions that no parent would knowingly want to pass on to a child. While most manifest themselves at birth or soon thereafter, Huntington's Disease does not develop until midlife when a person has already passed the gene on to a child. Woody Guthrie was a victim of the disease as was his mother and two of his daughters.
Hemophilia is one of the most well-known genetic disorders. It is believed to have been caused by a gene mutation in Queen Victoria. Her large family intermarried with many of the royal houses of Europe and members of several royal houses had it, the most famous being the son of Czar Alexander of Russia. Czarina Alexandra was so desperate to find a cure that she consulted the monk Rasputin, a crude and unpopular figure in Russia. The general disapproval over this association contributed to the unpopularity of the royal family which eventually lead to the revolution.
Porphyria is another royal disease with historical implications. One of the symptoms of this disease is bouts of madness and it is believed that King George III of England suffered from this genetic disorder which may have gone back to Mary, Queen of Scots.
Genetic testing has made great advances and in many cases a test can determine if a person is carrying a gene for a particular disease. In other cases there is no test, so how do you determine if those who have gone before you had a problem? As with all genealogy, you must use many resources.
What to Do with the Information
If you are simply predisposed towards a disease, you are mostly limited to being vigilant. However, there are some rather radical decisions that families with a predisposition to some types of cancer have been forced to make. Breast cancer and ovarian cancer can be a very real possibility if several of a woman's female relatives have had the disease. Some healthy woman have decided to have mastectomies or hysterectomies since the risk of getting these cancers was so great.
The odds for many hereditary defects can be accurately predicted through genetic counseling. People with family histories of these defects should receive testing and counseling before they have children so that they can make an intelligent decision on the risks involved.
It is well known that some diseases favor certain ethnicities. Ashkenazi Jews (Jews of Eastern European descent) stand a far higher statistical probability of having certain diseases including Gaucher disease, Bloom syndrome, Canavan disease and Tay-Sachs disease. This higher percentage probably comes from the history of these people being a small population who intermarried.
Sickle Cell Anemia occurs more frequently in African Americans. If both parents have the disease, all their children will have it. If one parent has it and the other is normal (not a carrier), all the children will be carriers. (A carrier does not suffer from the disease itself but "carries" the gene that could pass the disease on to descendants.) In addition, people of Mediterranean descent more often have thalassemia, and cystic fibrosis is more often found in persons of central European ancestry.
Some disorders are related to sex, the most famous being hemophilia. Women can only be carriers of the disease and only men are born with it.
How can it happen that two normal, healthy people can have a child with a hereditary disease? It happens the same way two brown-eyed parents can have a blue-eyed baby. Each person has two genes that control eye color but generally the eyes will only be one color. The gene for brown eyes is dominant over the gene for blue eyes. If a person has one brown-eye and one blue-eye gene, the brown will dominate over the blue and he will have brown eyes. However, the blue-eye gene is still there and can be passed on to a child. If two brown-eyed parents each have a brown-eye and blue-eye gene and the one the child inherits from each is for blue eyes, then the child will have blue eyes.
The same thing can happen if the gene causing the disease is recessive. Both parents could have inherited a healthy gene and a recessive gene for the disease. Since the healthy gene is dominant, the parents are healthy.
Predicting the Odds
There are many factors involved depending on which gene carries the defect, whether the gene is recessive or dominant and whether one or both parents have the disease or if one or both are carriers. However, in many cases the odds are completely predictable. If both parents are carriers, as above, 25% of the children will have the disease, 75% will be healthy but 50% will be carriers. If the gene is recessive and one parent has the disease and the other healthy, the children will not have it but all will be carriers. (Since the parent with the disease had to receive two genes with the disease in order to have it, he only has the disease ones to pass on.) These odds apply to each pregnancy. Even if the parents have a normal child, they need to be aware that the child may be a carrier.
Once you have gathered your family medical history, you should not go too far in trying to interpret it as you could jump to wrong conclusions. For example, if the women in your family who had breast cancer were all on your father's side, doctors say this does not increase your risk of getting cancer.
If there is a serious genetic defect in your family and you have not started a family, counseling would be a good idea. First would be the decision of whether or not to have children at all. For some people a 75% chance of a normal baby sounds good while others would not want to take a chance on a 25% possibility of a child that could never have a normal life or might not survive to its first birthday. In the case of Huntington's Disease, it would be very difficult to not know for many years whether or not you had passed on the disease. Even if you already have children, you may need to inform them of the family history and the fact that they may be carriers.
More and more is being done with genetics. Many of these genetic diseases will be curable in the future but you will be ahead of the game if you can identify through family history the areas that might be a problem for you.
Recording Your Information
Family Tree Maker has a place for you to record medical information and cause of death. You can also print this information on your charts so you can easily track the history of a disease once you have collected the information. It could save your life!
In the future, DNA will provide many of the answers that we have to scramble so hard now to find from documents and family histories. There are already organizations encouraging people to leave a sample of their DNA so future generations can find answers that are not available now. Wouldn't it have been nice if our ancestors could have left DNA samples that even today would have provided us with answers to a lot of questions. (Of course, it might also have proven that they weren't our ancestors!)
About the Author
I began genealogy in 1970 when we were living in Ogden, Utah for a short time. I was immediately hooked when, on my first visit to the local Family History Center, I found my great-grandparents in the 1850 Ohio census. I have been researching ever since on my own family and for others. I soon recognized the value of computer programs for keeping track of the data. I was a founding member of the Computer Genealogy Society of San Diego and editor of the newsletter. I have written a third party manual on ROOTS III and, with Joan Lowrey, authored two guides to genealogy software. Using ROOTS III and WordPerfect, I have written several family history books for others, but have yet to stop researching long enough to complete my own family history!