Practice Exam-Reproductive Genetics I and II

Reproductive Genetics I and II

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The document contains practice questions and analyses related to reproductive genetics. Here is a summary of each presented case:<br /><br />1. <strong>Case of a 22-Year-Old Pregnant Woman (Question ID 25239):</strong> The patient, at 13 weeks of gestation, displays a positive cfDNA screen for trisomy 13, but her 18-week fetal survey is normal. Despite being advised about potential risks and benefits, she declines further invasive testing. Given that the chance of trisomy 13 is significantly low considering age and normal fetal survey results, the recommended next step is to discuss the positive predictive value of cfDNA screening with her.<br /><br />2. <strong>Case of Mrs. Smith (Question ID 25238):</strong> Mrs. Smith, at 11 weeks of gestation, receives an "uninterpretable-insufficient fetal fraction" result from her noninvasive prenatal screening for aneuploidy. The most common reason is high BMI, which affects the fetal cell-free DNA fraction.<br /><br />3. <strong>Case of Mrs. Green (Question ID 25241):</strong> Mrs. Green, with a history of stillbirth suspected to be due to trisomy 18, seeks preimplantation genetic testing for aneuploidy due to past experiences. To ascertain recurrence risk, obtaining parental karyotypes is most appropriate as it could reveal a balanced translocation which might not be revealed through cfDNA alone.<br /><br />4. <strong>Infertility and IVF (Question ID 25240):</strong> Mr. and Mrs. Smith, facing unexplained infertility and planning IVF, are concerned about genetic risks in pregnancy. The recommended appropriate step before an IVF pregnancy is expanded genetic carrier screening, which may identify risk factors not apparent from standard tests.<br /><br />In all cases, the discussions focus on interpreting genetic screening results effectively and deciding on further testing or screening based on individual patient contexts and risks.

Keywords

reproductive genetics

cfDNA screening

trisomy 13

fetal survey

prenatal screening

fetal fraction

preimplantation genetic testing

balanced translocation

expanded genetic carrier screening

genetic risk assessment