Genetics and Teratology Extra Questions

1. You are counseling a 16-year-old G1P0 girl and her 16-year-old boyfriend. Two weeks ago they received a quad screen result with a 1:50 risk for Down syndrome. She has noninformative family history and medical history. You begin counseling by explaining that the number of chromosomes in a fetus is how many?

2. You are counseling a 16-year-old G1P0 girl and her 16-year-old boyfriend. Two weeks ago they received a quad screen result with a 1:50 risk for Down syndrome. She has noninformative family history and medical history. You counsel that the quad screen does which of the following?

3. You are counseling a 16-year-old G1P0 girl and her 16-year-old boyfriend. Two weeks ago they received a quad screen result with a 1:50 risk for Down syndrome. She has noninformative family history and medical history. You perform an ultrasound that places the fetus currently at 15½ weeks’ gestation. You should counsel which of the following?

4. You are counseling a 16-year-old G1P0 girl and her 16-year-old boyfriend. Two weeks ago they received a quad screen result with a 1:50 risk for Down syndrome. She has noninformative family history and medical history. If she decides she would like amniocentesis, you counsel her complications would include which of the following?

5. A 25-year-old G1P0, 20 weeks’ gestation has a family history of classic hemophilia. Her uncle on her mother’s side and her brother are affected. A perinatal ultrasound notes a male fetus. What is the chance that her son (in utero) will inherit hemophilia?

6. A 25-year-old G1P0, 20 weeks’ gestation has a family history of classic hemophilia. Her uncle on her mother’s side and her brother are affected. A perinatal ultrasound notes a male fetus. If her son does have the disease, he would be classified as which of the following?

7. A 25-year-old G1P0, 20 weeks’ gestation has a family history of classic hemophilia. Her uncle on her mother’s side and her brother are affected. A perinatal ultrasound notes a male fetus. In counseling this patient, she asks why her uncle died when he was 4 and her brother, now 17, has had little problem with the disease. You explain that the different expression of the gene relates is a result of which of the following?

8. A female who possesses an X-linked trait may do so because either she inherited a recessive gene from both her mother and her father or which of the following?

9. You are seeing a patient who has been exposed to a medication. You look it up in the register of pregnancy medications. It is listed as category C. The patient asks you what this means. Which of the following is your best response?

10. Approximately what percentage of spontaneous first-trimester abortions shows chromosomal abnormalities?

11. Live births of infants would demonstrate approximately what percentage of chromosomal abnormalities?

12. A 22-year-old woman and her husband are being counseled after a first-trimester miscarriage. She has no significant medical problems. Her physical examination is unremarkable and in counseling her you explain in lay terms that the most likely cause of her miscarriage is aneu-ploidy. Which of the following is the most common aneuploidy causing miscarriage?

13. A 19-year-old woman with a complaint of never having had menses comes to your office. Physical examination shows that she is 1.37 m tall and weighs 94 lb. She lacks breast and pubic hair development. There is webbing of her neck and cubitus valgus.
Which of the following would be the simplest, yet most useful, initial test to begin her evaluation?

14. A 19-year-old woman with a complaint of never having had menses comes to your office. Physical examination shows that she is 1.37 m tall and weighs 94 lb. She lacks breast and pubic hair development. There is webbing of her neck and cubitus valgus.
Given the description of this patient, which of the following is her most likely diagnosis?

15. Patients with a 45,XO karyotype are invariably of short stature because the locus responsible for short stature is located where?

16. Your patient’s previous child died at 8 weeks of age. Her family called it crib death, but the autopsy suggested a metabolic disease. Which of the following most commonly describes inborn errors of metabolism that are diagnosable in utero?

17. A couple is concerned about the safety of antenatal ultrasound. What should you counsel them regarding the procedure?

18. A woman with blood type O gave birth to an AB infant. She and her partner are quite concerned that there may be a mix-up in the nursery. What is the most likely diagnosis?

19. A baby presents with ambiguous genitalia. A full chromosome count is sent and will return in 72 hours. Your laboratory can perform a test for Barr body so you can provide a preliminary answer sooner. What is the Barr body?

20. A couple presents to your office during the ninth week of pregnancy. Their previous child was diagnosed with trisomy 18, so they are extremely anxious and would like prenatal diagnosis as early as possible. They have many questions about chorionic villus sampling (CVS).
Which of the following would be the best response to their questions about CVS? Which is the best answer?

21. A couple presents to your office during the ninth week of pregnancy. Their previous child was diagnosed with trisomy 18, so they are extremely anxious and would like prenatal diagnosis as early as possible. They have many questions about chorionic villus sampling (CVS).
You explain to the couple that complications of CVS include which of the following?

22. A mother with blood group AB has an AB child. She would like to establish paternity through blood typing. Which blood type excludes a male from being the potential biologic father?

23. A woman presents from prenatal diagnosis requesting amniocentesis. Of the following issues in a patient history, which would be better diagnosed with ultrasound over amniocentesis?

24. A pregnant woman presents to your clinic with a history of a previous child who was diagnosed with phenylketonuria (PKU) as a neonate. Her partner is not the father of the first child. The mother remembers that she had to have a special diet when she was a child. In counseling her, you should explain which of the following?

25. A couple presents wanting to know the likelihood of recurrence of certain inherited traits. Which of the following is an autosomal dominant inheritance that gives the couple a 50/50 chance of recurrence with their next pregnancy?