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::'''Correct:''' Patients with Down Syndrome are at an increased risk of ALL and AML.
Answer B	AnswerB::Atherosclerosis
Answer B Explanation	AnswerBExp::'''Incorrect:''' 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::'''Incorrect:''' 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::'''Incorrect:''' Down syndrome patients have a markedly decreased risk of most solid tumors except for testicular cancer.
Answer E	AnswerE::Hyperthyroidism
Answer E Explanation	AnswerEExp::'''Incorrect:''' 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 of Down syndrome include: Abnormally small chin Flat nasal bridge Single palmar fold (simian crease) A protruding tongue Excessive space between the large toe and second toe (pictured above) 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. Wiki-mnemomic: AFP goes DOWN in Down syndrome. Educational Objective: Down syndrome is associated with an increased risk of ALL. References: First Aid 2012 page 93. Educational Objective: References: ]]
Approved	Approved::Yes
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