WBR0544: Difference between revisions

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|MainCategory=Genetics, Microbiology, Pathology
|MainCategory=Genetics, Microbiology, Pathology
|SubCategory=Neurology
|SubCategory=Neurology
|MainCategory=Genetics, Microbiology, Pathology
|MainCategory=Genetics, Microbiology, Pathology
|MainCategory=Genetics, Microbiology, Pathology
|MainCategory=Genetics, Microbiology, Pathology
|MainCategory=Genetics, Microbiology, Pathology
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|MainCategory=Genetics, Microbiology, Pathology
|MainCategory=Genetics, Microbiology, Pathology
|SubCategory=Neurology
|SubCategory=Neurology
|Prompt=A 14-year-old male is brought to the physician's office by his mother for a recent-onset headache, vomiting, and ataxia. Following appropriate work-up, the patient is found to have hemangioblastoma in the cerebellum and renal cell carcinomas bilaterally.  Genetic testing leads to a diagnosis.  Which of the following findings is most likely associated with the patient's condition?
|Prompt=A 14-year-old male is brought to the physician's office by his mother for recent-onset headache, vomiting, and ataxia. Following appropriate work-up, the patient is found to have hemangioblastoma in the cerebellum and renal cell carcinomas bilaterally.  Genetic testing leads to a diagnosis.  Which of the following findings is most likely associated with the patient's condition?
|Explanation=The patient has von Hippel-Lindau (VHL) disease, an autosomal dominant inherited disorder, caused by the deletion of the VHL gene on chromosome 3.  VHL is characterized by hemangioblastomas of the retina, cerebellum, and medulla.  Also patients frequently present with bilateral renal cell carcinomas or other tumors, such as pheochromocytomas.  A common manifestation of VHL in young patients are headaches with neurological symptoms.  Symptoms of other tumors may also manifest, such as hypertension in the case of pheochromocytoma.
|Explanation=The patient has von Hippel-Lindau (VHL) disease, an autosomal dominant disorder caused by germline mutation of one copy of the VHL tumor suppressor gene on chromosome 3.  VHL is characterized by hemangioblastomas of the retina, cerebellum, and medulla.  Also patients frequently present with bilateral renal cell carcinomas or other tumors, such as pheochromocytomas.  A common manifestation of VHL in young patients are headaches with neurological symptoms.  Symptoms of other tumors may also manifest, such as hypertension in the case of pheochromocytoma.
 
The VHL gene product, E3 ubiquitin ligase, which normally targets hypoxia-induced factor (HIF) in the presence of oxygen for destruction, is absent in VHL.  As a result, polycythemia is a finding associated with VHL, due to the overproduction of hypoxia-induced factor (HIF). 
 
|EducationalObjectives= Polycythemia is associated with VHL, due to an overproduction of HIF.
 
|References= Kaelin WG. The von Hippel-Lindau tumor suppressor gene and kidney cancer. Clin Cancer Res. 2004; 10(18 Pt 2):6290S-5S


The VHL gene product, E3 ubiquitin ligase, which normally targets hypoxia-inducible factor (HIF) in the presence of oxygen for destruction, is absent in VHL.  As a result, polycythemia is a finding associated with VHL, due to the overproduction of hypoxia-induced factor (HIF).
|AnswerA=Hematocrit (Hct) = 58 %
|AnswerA=Hematocrit (Hct) = 58 %
|AnswerAExp=Polycythemia is associated with VHL.
|AnswerAExp=Polycythemia is associated with VHL.
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|AnswerE=Serum calcium = 13 mmol/L
|AnswerE=Serum calcium = 13 mmol/L
|AnswerEExp=Hypercalcemia is not frequently associated with VHL.
|AnswerEExp=Hypercalcemia is not frequently associated with VHL.
|EducationalObjectives=Polycythemia is associated with VHL, due to an overproduction of HIF.
|References=Kaelin WG. The von Hippel-Lindau tumor suppressor gene and kidney cancer. Clin Cancer Res. 2004; 10(18 Pt 2):6290S-5S
|RightAnswer=A
|RightAnswer=A
|WBRKeyword= von hippel lindau, polycythemia, hematocrit, HCT, hemangioblastoma, bilateral renal cell carcinoma, headache, vomiting, pheochromocytoma, hypoxia induced factor, HIF, autosomal, autosomal dominant, genetics, genes, pattern of inheritance, inheritance, mutation, deletion
|WBRKeyword=von hippel lindau, polycythemia, hematocrit, HCT, hemangioblastoma, bilateral renal cell carcinoma, headache, vomiting, pheochromocytoma, hypoxia induced factor, HIF, autosomal, autosomal dominant, genetics, genes, pattern of inheritance, inheritance, mutation, deletion
|Approved=Yes
|Approved=Yes
}}
}}

Revision as of 18:40, 17 January 2015
Author [[PageAuthor::Rim Halaby, M.D. [1], Alison Leibowitz [2] (Reviewed by Alison Leibowitz)]]
Exam Type ExamType::USMLE Step 1
Main Category MainCategory::Genetics, MainCategory::Microbiology, MainCategory::Pathology
Sub Category SubCategory::Neurology
Prompt [[Prompt::A 14-year-old male is brought to the physician's office by his mother for recent-onset headache, vomiting, and ataxia. Following appropriate work-up, the patient is found to have hemangioblastoma in the cerebellum and renal cell carcinomas bilaterally. Genetic testing leads to a diagnosis. Which of the following findings is most likely associated with the patient's condition?]]
Answer A AnswerA::Hematocrit (Hct) = 58 %
Answer A Explanation AnswerAExp::Polycythemia is associated with VHL.
Answer B AnswerB::Serum sodium = 122 mmol/L
Answer B Explanation AnswerBExp::Hyponatremia is not frequently associated with VHL.
Answer C AnswerC::Serum alanine aminotransaminase (ALT) = 241 IU/L
Answer C Explanation AnswerCExp::Elevated ALT is not frequently associated with VHL.
Answer D AnswerD::Platelet count = 43,000 per microliter
Answer D Explanation AnswerDExp::Thrombocytopenia is not frequently associated with VHL.
Answer E AnswerE::Serum calcium = 13 mmol/L
Answer E Explanation AnswerEExp::Hypercalcemia is not frequently associated with VHL.
Right Answer RightAnswer::A
Explanation [[Explanation::The patient has von Hippel-Lindau (VHL) disease, an autosomal dominant disorder caused by germline mutation of one copy of the VHL tumor suppressor gene on chromosome 3. VHL is characterized by hemangioblastomas of the retina, cerebellum, and medulla. Also patients frequently present with bilateral renal cell carcinomas or other tumors, such as pheochromocytomas. A common manifestation of VHL in young patients are headaches with neurological symptoms. Symptoms of other tumors may also manifest, such as hypertension in the case of pheochromocytoma.

The VHL gene product, E3 ubiquitin ligase, which normally targets hypoxia-inducible factor (HIF) in the presence of oxygen for destruction, is absent in VHL. As a result, polycythemia is a finding associated with VHL, due to the overproduction of hypoxia-induced factor (HIF).
Educational Objective: Polycythemia is associated with VHL, due to an overproduction of HIF.
References: Kaelin WG. The von Hippel-Lindau tumor suppressor gene and kidney cancer. Clin Cancer Res. 2004; 10(18 Pt 2):6290S-5S]]

Approved Approved::Yes
Keyword WBRKeyword::von hippel lindau, WBRKeyword::polycythemia, WBRKeyword::hematocrit, WBRKeyword::HCT, WBRKeyword::hemangioblastoma, WBRKeyword::bilateral renal cell carcinoma, WBRKeyword::headache, WBRKeyword::vomiting, WBRKeyword::pheochromocytoma, WBRKeyword::hypoxia induced factor, WBRKeyword::HIF, WBRKeyword::autosomal, WBRKeyword::autosomal dominant, WBRKeyword::genetics, WBRKeyword::genes, WBRKeyword::pattern of inheritance, WBRKeyword::inheritance, WBRKeyword::mutation, WBRKeyword::deletion
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