Sunday, May 31, 2009

Genetic Tests

There are some tests to expect when you are pregnant and some that you can request even before you conceive. Depending on your ethnicity, you may request a test to genetically rule you out as a carrier for some chromosomal disorders. Testing ahead of a pregnancy gives you information about YOUR genetic make-up. If you test positive to a recessive disorder where you and your partner both have the gene, then you know your baby is at a statistical increased risk. If you test negative, it doesn't much matter what your partner tests, because there is no increased risk. In recessive disorders, both parents have to be carriers.

If you are of African extraction, you may want to see if you carry the gene for sickle cell. Like many genetic disorders, you can be a carrier and never know it and NOT have the condition. But if you and your partner both "carry" the gene as part of your chromosomal make-up, your offspring are at increased risk for getting both those recessive genes and may indeed inherit sickle cell disease. So, it is often the female who is tested and then if she has the gene, father of baby should be tested too. Even if there is NO sickle cell disease in your family, you could be a carrier.

Jewish people of Eastern European extraction ( Askenasic Jews ) are at risk for being carriers of a host of genetic disorders. There is a special battery of tests that are grouped together by the lab that can give a great deal of information about YOUR ( not the baby's ) genetic composition. There are many genetic disorders that can be recessive, so again, if one of you tests postive, the other should be tested for those disorders also. If both parents are carriers, then the baby is at increased risk of inheriting the disease. And alot of parents would like to know before they even try to conceive.

Cysytc Fibrosis is one test on the Jewish panel that can affect other ethnicities. You can be tested for CF even if you are not Jewish. If you have one of the 97 mutations, it is posible to pass on the gene to your child, so you should see if your partner might carry the same mutation. Tay-Sachs can also affect Cajuns and French Canadians, not just people of Eastern European Jewish ancestry.

All of these tests are done with a blood sample. No fancy invasive tests are necesary to test YOUR genetic make-up. CVS and amniocentisis are tests to test your BABY'S genetic make-up. They are reserved for cases where your baby might be at increased risk for a chromosomal disorder and you want to know ahead of completing the pregnancy. These tests increase the risk ( slightly ) for miscarriage but provide alot of information that you may want to know. Information is for your use and for the use of your physicians, so they can let you know, ahead of time, what to expect and to get the needed services that you may want well before the baby is born.

Women who are over the age of 35 are at increased risk for Down's Syndrome just because of their age. It is thought that eggs age and statistically 35 years is the cut-off for Trisomy 21. This doesn't mean that all thirty- five year old women are going to have a baby with this chromosomanl disorder, but many know that they want to know, since they are at increased risk. There is a very good screening tool for Down's Syndrome ( First Screen or Nuchal Translucency ) but this is NOT a genetic test. Only chorionic villus sampling or amniocentesis is a true genetic test for your baby's genetic blueprint ( karyotype ).

Talk to your doctors and nurses about all of these tests and choices. Ask for a referral to a counselor if you need more help in determining which tests may be appropriate for your family. Information is for your use and the use of your healthcare providers in getting you and your family the best care possible. It is not an invitation to necessarily terminate a pregancy. In this country, that is YOUR choice. But knowing what disorders you may be at risk for and knowing which disorders your baby carries will certainly make a difference in your preparedness and the level of care that you and your baby receive by virtue of that information. Be informed and then make up your own mind.

If you think that you are at an increased risk for genetic, inherited disorders, you may request genetic counseling to evaluate which tests might be appropriate for your family. You may decide to have the tests even if you do not avail yourself of this counseling. Your primary care doctor, or your obstetrician/ gynecologist can easily order these tests for you. Boy scouts and parents should be prepared.