Medical Genetics Online Tests (3) With Possible Answers
3. A young couple both affected with classical achondroplasia 你们e to you for genetic counseling. There is no other family history of achondroplasia. You should inform them that if they have a tull term liveborn, the probability that the newborn wi11 not have achondroplas if about: (4.0分) A. 25% B. < 1% C. 33% D. 50%
22. A 34-year-old woman presents to the emergency room with burning, stabbing, epigastric abdominal pain. She reports nausea and vomiting over the past 24 hours and states that she thinks that she may be pregnant. Urinalysis is positive for ketones, WBCs, RBCs, and bacteria. Pregnancy test is positive. An abdominal CT reveals thromboses in the splenic, superior mesenteric, and left renal and portal veins. Further testing reveals a factor V Leiden mutation in one allele. There is no family history of thrombosis disorders in her family or her husband’s family. Further analysis reveals a mutation in the mother’s factor V Leiden gene; the father does not have the mutation. The patient is concerned about her pregnancy in light of these findings. What is the probability her child will be affected by factor V Leiden thrombophila? (4.0分) A. 25%
B. Virtually 0% C.50% D.75% E.100%
First trimester tests during pregnancy
Here are some tests you may undergo during the first trimester of your pregnancy:
Blood tests: During one of your initial examinations, your doctor or midwife will identify your blood type and Rh (rhesus) factor, screen for anemia, check for immunity to rubella (German measles), and test for hepatitis B, syphilis, and HIV and other sexually transmitted diseases.
Depending on racial, ethnic, or family background, you may be offered tests and genetic counseling to assess risks for diseases such as Tay-Sachs, cystic fibrosis, and sickle cell anemia (if these weren't done at a preconception visit). Tests for exposure to diseases such as toxoplasmosis and varicella (the virus that causes chickenpox) may also be done if needed. Your health care provider may also want to check your levels of hCG, a hormone secreted by the placenta, and/or progesterone, a hormone that helps maintain the pregnancy.
Urine tests: You will also be asked early on for a urine sample so that your doctor or midwife can look for signs of kidney infection and, if necessary, to confirm your pregnancy by measuring the hCG level. (A blood hCG test to confirm pregnancy may be used instead.) Urine samples will then be collected regularly to detect glucose (a sign of diabetes) and albumin (a protein that may indicate preeclampsia, pregnancy-induced high blood pressure).
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Chorionic villus sampling (CVS): If you're 35 or older or have a family history of certain diseases, you will be offered this optional, invasive test usually between 10 and 12 weeks of pregnancy. CVS can detect many genetic defects, such as Down syndrome, sickle cell anemia, cystic fibrosis, hemophilia, and muscular dystrophy. The procedure involves either threading a tiny catheter through your cervix or inserting a needle into your abdomen to obtain a tissue sample from the placenta. The procedure carries a 1% risk of inducing miscarriage and is about 98% accurate in ruling out certain chromosomal birth defects. But, in contrast to amniocentesis, it does not help in detecting neural tube disorders, such as spina bifida and anencephaly, or abdominal wall defects.
A promising new procedure that 你们bines a blood test with an ultrasound to screen for Down syndrome may be available between 11 and 14 weeks of pregnancy. The results of a blood test that measures hCG and/or PAPP-A (pregnancy-associated plasma protein A) in maternal blood are used with an ultrasound measurement of the skin at the back of the fetus’ neck (called nuchal translucency). The procedure may be able to pick up a substantial portion of Down syndrome cases and other genetic conditions. However, as with all screening methods, a more invasive diagnostic technique like CVS is used if results are positive.
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Medical Genetics Online Tests 3——医学遗传学
