WBR0116
| Author | PageAuthor::Mahmoud Sakr (Reviewed by Will Gibson) |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Genetics |
| Sub Category | SubCategory::Gastrointestinal |
| Prompt | [[Prompt::A 33-year-old Caucasian female presents with diarrhea and foul-smelling bulky stools for the past 3 weeks. She has tried several over the counter medications with no relief. Yesterday, she noticed an eruption of intensely pruritic papules and vesicles on her elbows, dorsal forearms and back. She recalls that her older brother has suffered from a similar illness for approximately 5 years. Her vital signs and initial labs are unremarkable. Serologic testing revealed elevated levels of IgA tissue transglutaminase antibodies. Which of the following gene mutations most likely predisposed this patient's condition?]] |
| Answer A | AnswerA::HLA DQ2 gene |
| Answer A Explanation | [[AnswerAExp::This patient suffers from celiac disease or gluten-sensitive enteropathy, which is genetically predisposed by HLA DQ2 or HLA DQ8 gene mutations.]] |
| Answer B | AnswerB::IBD1 gene |
| Answer B Explanation | AnswerBExp::IBD1 encodes an intracellular pattern recognition receptor (NOD2). IBD1 mutations are associated with inflammatory bowel diseases. |
| Answer C | AnswerC::HLA-DR2 |
| Answer C Explanation | [[AnswerCExp::HLA-DR2 is associated with inflammatory bowel diseases.]] |
| Answer D | AnswerD::APC gene |
| Answer D Explanation | [[AnswerDExp::APC gene mutation predisposes to familial adenomatous polyposis.]] |
| Answer E | AnswerE::MSH2 gene |
| Answer E Explanation | [[AnswerEExp::MSH2 gene mutation is associated with Hereditary nonpolyposis colorectal cancer.]] |
| Right Answer | RightAnswer::A |
| Explanation | [[Explanation::This patient suffers from celiac disease or gluten-sensitive enteropathy. Celiac disease is an autoimmune disease of the small intestine that occurs in genetically predisposed people of all ages from middle infancy onward. Symptoms include pain and discomfort in the digestive tract, chronic diarrhea, failure to thrive (in children), anemia and fatigue, but these may be absent, and symptoms in other organ systems have been described. Celiac disease is genetically predisposed by HLA-DQ2 or HLA-DQ8 HLA subtypes. Educational Objective: Celiac disease or gluten-sensitive enteropathy, which is genetically predisposed by HLA-DQ2 or HLA-DQ8 HLA subtypes. |
| Approved | Approved::Yes |
| Keyword | WBRKeyword::Celiac disease; HLA-DQ2; HLA-DQ8; HLA; diarrhea; chronic diarrhea |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |