WBR0110
| Author | PageAuthor::William J Gibson |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Genetics |
| Sub Category | SubCategory::Cardiology, SubCategory::Musculoskeletal/Rheumatology |
| Prompt | [[Prompt::A 16 year old male presents to his pediatrician to be evaluated for scoliosis. The physician notes that in addition to his scoliosis, the patient is unusually tall, and has pectus excavatum. The physician suspects a genetic origin for the patient’s condition. Which of the following could potentially be used to treat this patient’s condition?]] |
| Answer A | AnswerA::Losartan |
| Answer A Explanation | AnswerAExp::Correct - Angiotensin receptor blockers have been shown to be useful in patient’s with Marfan syndrome. |
| Answer B | AnswerB::Lisinopril |
| Answer B Explanation | AnswerBExp::Incorrect - ACE-inhibitors are used for hypertension and diabetic renal disease. |
| Answer C | AnswerC::Hydrochlorothiazide |
| Answer C Explanation | AnswerCExp::Incorrect - Hydrochlorothiazide is a thiazide diuretic which is used to treat hypercalciuria and nephrogenic diabetes insipidus. |
| Answer D | AnswerD::Spironolactone |
| Answer D Explanation | AnswerDExp::Incorrect - Spironolactone is a potassium sparing diuretic and a competitive aldosterone receptor antagonist. It has antiandrogenic side effects. |
| Answer E | AnswerE::Furosemide |
| Answer E Explanation | AnswerEExp::Incorrect - Furosemide is a loop diuretic used in the treatment of congestive heart failure and edema. |
| Right Answer | RightAnswer::A |
| Explanation | [[Explanation::The patient in this vignette is suffering from Marfan Syndrome. Marfan syndrome is a genetic disorder of the connective tissue. People with Marfan tend to be unusually tall, with long limbs and long, thin fingers. Marfan syndrome has a range of expressions, from mild to severe. The most serious complications are defects of the heart valves and aorta. Marfan syndrome is a dominant genetic trait, meaning that people who inherit only one copy of the Marfan FBN1 gene from either parent will develop Marfan syndrome.
The syndrome is carried by the gene FBN1, which encodes the connective protein fibrillin-1. Fibrillin-1 protein is essential for the proper formation of the extracellular matrix, including the biogenesis and maintenance of elastic fibers. In addition to being a connective protein that forms the structural support for tissues outside the cell, the normal fibrillin-1 protein binds to another protein,transforming growth factor beta (TGF-β). TGF-β has deleterious effects on vascular smooth muscle development and the integrity of the extracellular matrix. Fibrillin-1 directly binds a latent form of TGFβ, keeping it sequestered and unable to exert its biological activity. Researchers now believe, secondary to mutated fibrillin, excessive TGF-β at the lungs, heart valves, and aorta weakens the tissues and causes the features of Marfan syndrome. Because angiotensin receptor blockers block TGF-Beta activity, they have been used to treat Marfan Syndrome with some efficacy. References: First Aid page 90. Tags: #Genetics #Cardiology |
| Approved | Approved::Yes |
| Keyword | |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |