WBR0369
| Author | [[PageAuthor::Gonzalo A. Romero, M.D. [1]]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Biochemistry, MainCategory::Pathology, MainCategory::Pathophysiology |
| Sub Category | SubCategory::Neurology |
| Prompt | [[Prompt::A research lab develops a new knock-in mouse model with a chimeric mouse/human exon containing 140 CAG repeats inserted into a gene located on the short arm of chromosome 4. The mice are grown and observed for 18 months. All mice develop increased locomotor activity and abnormal posturing around 1 month of age, followed by hypoactivity at 4 months and gait abnormalities at 1 year. Which of the following neurochemical changes is associated with this syndrome?]] |
| Answer A | AnswerA::Decreased norepinephrine, Decreased serotonin, Decreased dopamine |
| Answer A Explanation | [[AnswerAExp::These are the neurotransmitter changes associated in depression]] |
| Answer B | AnswerB::Increased norepinephrine, Increased serotonin, Increased dopamine |
| Answer B Explanation | [[AnswerBExp::This is seen in schizophrenia]] |
| Answer C | AnswerC::Increased acetylcholine, Increased serotonin, Decreased dopamine |
| Answer C Explanation | [[AnswerCExp::These changes are seen in parkinson’s disease]] |
| Answer D | AnswerD::Decreased GABA, Decreased acetylcholine, Increased dopamine |
| Answer D Explanation | AnswerDExp::These changes are associated with Huntington disease. |
| Answer E | AnswerE::Increased norepinephrine, Decreased GABA, Decreased serotonin |
| Answer E Explanation | [[AnswerEExp::These neurotransmitter changes are seen in anxiety]] |
| Right Answer | RightAnswer::D |
| Explanation | [[Explanation::This animal model is trying to develop Huntington disease in the monkeys, which is caused by a trinucleotide repeat (CAG), which caused damage to the caudate nucleus. Biochemically; human brains affected with this autosomal dominant disease have decreased GABA and Ach, increased DA.
References: First Aid 2013 page 461 |
| Approved | Approved::No |
| Keyword | |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |