WBR0311
| Author | PageAuthor::William J Gibson |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Genetics |
| Sub Category | SubCategory::Hematology, SubCategory::General Principles |
| Prompt | [[Prompt::A 5 month old female is evaluated in a well child visit. The child was born without complications via vaginal delivery to a gravida 2 para 2, 39-year-old woman.The child has skin folds covering the inner angle of the eye, a flat nasal bridge, and small chin; her feet are pictured below. Which of the following is the child at increased risk of?
|
| Answer A | AnswerA::Acute Lymphoblastic Leukemia |
| Answer A Explanation | AnswerAExp::Patients with Down syndrome are at an increased risk of ALL and AML. |
| Answer B | AnswerB::Atherosclerosis |
| Answer B Explanation | AnswerBExp::Down syndrome patients tend to have a decreased risk of atherosclerosis. Other cardiovascular abnormalities are associated with Down syndrome including endocardial cushion defects and atrial septal defects. |
| Answer C | AnswerC::Crohn’s disease |
| Answer C Explanation | AnswerCExp::Down syndrome is not associated with an increased risk of Crohn’s disease. Other gastrointestinal abnormalities are associated with Down syndrome including: duodenal atresia, annular pancreas and imperforate anus. |
| Answer D | AnswerD::Lung cancer |
| Answer D Explanation | AnswerDExp::Down syndrome patients have a markedly decreased risk of most solid tumors except for testicular cancer. |
| Answer E | AnswerE::Hyperthyroidism |
| Answer E Explanation | AnswerEExp::Down syndrome patients have no increased risk of hyperthyroidism. These patients are at an increased risk of hypothyroidism (one third of patients). |
| Right Answer | RightAnswer::A |
| Explanation | [[Explanation::The patient in this vignette has Down syndrome. Down syndrome is a chromosomal abnormality caused by an extra copy of chromosome 21. It is typically associated with physical growth delays, a particular set of facial characteristics and a severe degree of intellectual disability. Some of the physical characteristics associated with Down syndrome include:
Down syndrome is most often caused by meiotic nondisjunction, which occurs during meiosis I. Approximately 2-3% of cases are caused by Robertsonian translocation. On quad screen, Down syndrome is associated with decreased AFP, increased beta-HCG, decreased estriol and increased inhibin A. Note that non-invasive tests using fetal DNA detected in maternal blood are beginning to replace the quad screen for aneuploidy testing. Knowledge of this testing option may be fair game on the USMLE. Mnemomic: AFP goes DOWN in Down syndrome. Down syndrome is associated with the development of several diseases, including Alzheimer's disease and Acute Lymphocytic Leukemia (ALL). The precise reasons why Down syndrome increases the probability of developing ALL is unknown. |
| Approved | Approved::Yes |
| Keyword | WBRKeyword::Down syndrome, WBRKeyword::Cancer, WBRKeyword::Leukemia, WBRKeyword::Acute Lymphocytic Leukemia, WBRKeyword::Chromosome, WBRKeyword::Genetics |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |
