WBR0312
| Author | [[PageAuthor::William J Gibson (Reviewed by Yazan Daaboul, M.D.)]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Genetics |
| Sub Category | SubCategory::General Principles |
| Prompt | [[Prompt::A newborn girl is born via cesarean section to a 42-year-old primigravid woman. The child has microcephaly with a prominent occiput, low-set ears, cleft palate, and rocker-bottom feet with webbed toes. An image of the patient’s hands is shown below. What is the median lifespan that is associated with this patient's condition?
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| Answer A | AnswerA::50 to 60 years |
| Answer A Explanation | AnswerAExp::Sixty years is the median lifespan of patients with Down Syndrome. However, many patients with Down syndrome are affected by Alzheimer’s disease between the ages of 40 and 50. |
| Answer B | AnswerB::10 to 15 years |
| Answer B Explanation | AnswerBExp::Ten years is the median lifespan of patients with progerioid syndromes such as Hutchinson-Gilford progeria. |
| Answer C | AnswerC::1 to 2 years |
| Answer C Explanation | AnswerCExp::One year is the median lifespan of patients with Patau syndrome. Patau syndrome is caused by an extra copy of chromosome 13 (trisomy 13). |
| Answer D | AnswerD::1 to 2 weeks |
| Answer D Explanation | AnswerDExp::Among those who survive, patients with Edwards' syndrome have a median lifespan of approximately 1 week (5 to 15 days). |
| Answer E | AnswerE::1 to 2 days |
| Answer E Explanation | AnswerEExp::The median lifespan of anencephaly is on the order of approximately one day. |
| Right Answer | RightAnswer::D |
| Explanation | [[Explanation::Edwards' syndrome is a chromosomal abnormality caused by the presence of all or part of an extra 18th chromosome (trisomy 18). Approximately 80% of patients with Edward's syndrome are female. The majority of fetuses with the syndrome die before birth; those who survive have a median lifespan of approximately 1 to 2 weeks. Fewer than 10% of patients with Edwards' syndrome live beyond 1 year. The physical characteristics of Edwards' syndrome include the following:
Educational Objective: Edwards' syndrome is a chromosomal abnormality of chromosome 18 (trisomy 18) with severe abnormal facies and symptoms. The majority of patients with Edwards' syndrome die before birth. Among those who survive, the median lifespan of live births is approximately 1 to 2 weeks. |
| Approved | Approved::Yes |
| Keyword | WBRKeyword::Edwards syndrome, WBRKeyword::Edwards' syndrome, WBRKeyword::Trisomy 18, WBRKeyword::Chromosome, WBRKeyword::Chromosomal Abnormality, WBRKeyword::Aneuploidy, WBRKeyword::Newborn, WBRKeyword::Median lifespan, WBRKeyword::Lifespan, WBRKeyword::Median life expectancy, WBRKeyword::Life expectancy |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |
