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{{WBRQuestion
{{WBRQuestion
|QuestionAuthor={{Rim}}
|QuestionAuthor= {{YD}} (Reviewed by William J Gibson)
|ExamType=USMLE Step 1
|ExamType=USMLE Step 1
|MainCategory=Pathology
|MainCategory=Pathology
Line 21: Line 21:
|MainCategory=Pathology
|MainCategory=Pathology
|SubCategory=Neurology
|SubCategory=Neurology
|Prompt=A 37 year old male known to have Down syndrome, was brought by his family for troubles in his memory. The family reports that the patient’s memory has been deteriorating for the last year.  He does not recall the names of hi brothers and sisters and find difficulty finding words. He is unable to find his way back home and get lost when a member of his family does not assist him. He has also recently been more dependent on his family.  The pathological evaluation of this patient’s neurons will most likely demonstrate which of the following?
|Prompt=A 41-year-old man with Down syndrome is brought to the family's physician for cognitive decline. The family reports that the patient’s memory has been deteriorating for the past year.  He cannot recall the names of his brothers and sisters and often has difficulty finding words. He is unable to find his way back home and gets lost when a member of his family does not assist him. Which of the following neuropathologic changes is most likely present in this patient?
|Explanation=Patient’s with [[Down syndrome]] have high risk of developing [[Alzheimer’s]] disease at an early age. Neurofibrillary tangles are pathological protein aggregates found within neurons in cases of Alzheimer's disease.
|Explanation=This patient is most likely diagnosed with [[Alzheimer's disease]]. Although Alzheimer's disease is most commonly diagnosed in the elderly, patients with [[Down syndrome]] are at high risk of developing [[Alzheimer’s]] disease at an early age. The presence of an extra chromosome 21 is thought to result in a significant increase in the synthesis of amyloid precursor proteins (APP) that are encoded by chromosome 21. Subsequently, the increase in the amyloidogenic parts leads to early-onset senile plaque formation and Alzheimer's disease. The disease is characterized by the presence of diffuse cortical atrophy with a decrease in acetylcholine (Ach) neutrotransmitter concentration in the brain. Neurofibrillary tangles (shown below) are abnormal proteins present in neurons of patients with Alzheimer's disease. These tangles are formed by hyperphosphorylation of the tau protein, a microtubule-associated protein that causes the tangles to aggregate in an insoluble form. In addition to alterations in APP protein, other proteins are also associated with either early-onset Alzheimer's disease (such as presinilin-1 protein [chromosome 14] and presenilin-2 protein [chromosome 1]) or late-onset Alzheimer's disease (such as ApoE4 [chromosome 19]). On the other hand, ApoE2 protein [chromosome 19] is considered protective against Alzheimer's disease.
<br>
[[File:NFT_9_2_14.JPG |400px| alt = Neurofibrillary tangle in the hippocampus of AD patient |Neurofibrillary tangle (red arrow)]]
|AnswerA=Neurofibrillary tangles
|AnswerA=Neurofibrillary tangles
|AnswerAExp=Neurofibrillary tangles are pathological protein aggregates found within neurons in cases of Alzheimer's disease. Tangles are formed by hyperphosphorylation of a microtubule-associated protein known as tau, causing it to aggregate in an insoluble form.  Patient’s with Down syndrome have high risk of developing Alzheimer’s disease at an early age.
|AnswerAExp=Neurofibrillary tangles are abnormal aggregates of proteins within neurons of patients with Alzheimer's disease. Patient’s with Down syndrome have a high risk of developing Alzheimer’s disease at an early age due to increased gene dosage of the amyloid precursor protein (APP) on chromosome 21.
|AnswerB=Pick’s bodies
|AnswerB=Pick bodies
|AnswerBExp=[[Pick bodies]] are silver-staining, spherical aggregations of tau protein in neurons associated with Pick's disease, a subtype of frontotemporal lobar degeneration. The symptoms of Pick’s disease include memory deterioration in addition to mood and personality changes.
|AnswerBExp=[[Pick bodies]] are silver-staining, spherical aggregations of tau protein in neurons that are associated with Pick's disease, a subtype of frontotemporal lobar degeneration. While Pick’s disease is characterized by memory loss, it is distinguished from Alzheimer's disease by severe mood and personality changes.
|AnswerC=Negri bodies
|AnswerC=Negri bodies
|AnswerCExp=[[Negri bodies]] are eosinophilic, sharply outlined, pathognomonic inclusion bodies (2–10 µm in diameter) found in the cytoplasm of certain nerve cells containing the virus of rabies. Rabies cause acute encephalitis, and it is generally preceded by an animal bite.
|AnswerCExp=[[Negri bodies]] are eosinophilic, sharply-outlined inclusion bodies in neurons of patients with rabies virus. Rabies virus is usually transmitted by an animal bite; it causes acute encephalitis and death among patients who develop symptoms.
|AnswerD=Lewy bodies
|AnswerD=Lewy bodies
|AnswerDExp=Lewy bodies are abnormal aggregates of protein that develop inside nerve cells. The main disease associated with the presence of Lewy bodies is [[Parkinson's disease]]. Lewy bodies are also present in [[neurons]] in dementia with Lewy bodies and the Lewy body variant of Alzheimer's disease.
|AnswerDExp=Lewy bodies are abnormal aggregates of alpha-synuclein protein that develop in neurons. The most common disease associated with the presence of Lewy bodies is [[Parkinson's disease]]. Lewy bodies are also present in [[neurons]] of patients with Lewy body dementia, a subtype of dementia characterized by symptoms of dementia followed by early parkinsonism (early disability and falls within 1 year of symptoms, in contrast to late disability in [[parkinson's disease]]), [[hallucination]]s (''visual'' mostly, in contrast to schizophrenia-associated ''auditory'' hallucinations), and [[neuroleptic sensitivity]].
|AnswerE=Spongioform changes
|AnswerE=Spongioform changes
|AnswerEExp=Spongiform change in the gray matter is the classical presentation for [[Creutzfold Jacob disease]]. It is characterized by the presence of many round vacuoles from one to 50 micrometre, in all six cortical layers in the cerebral cortex or with diffuse involvement of the cerebellar molecular layer.  These vacuoles appear glassy or eosinophilic and may coalesce.  Neuronal loss and gliosis are also seen.
|AnswerEExp=Spongioform change in the gray matter is the pathological hallmark of [[Creutzfeldt-Jakob disease]]. It is characterized by a "spongy appearance" of the cerebral cortex due to the presence of many round vacuoles.
|EducationalObjectives=Neurofibrillary tangles are pathological protein aggregates found within neurons in cases of Alzheimer's disease.
|EducationalObjectives=Neurofibrillary tangles are pathological protein aggregates found within neurons in cases of Alzheimer's disease.
|References=First Aid 2014 page 90 (Down Syndrome) ; First Aid 2014 page 483 (Alzheimer's disease)
|References=Lott IT, Head E. Down syndrome and Alzheimer's disease: a link between development and aging. Ment Retard Dev Disabil Res Rev. 2001;7(3):172-8.<br>
Glenner GG, Wong CW. Alzheimer's disease and Down's syndrome: sharing of a unique cerebrovascular amyloid fibril protein. Biochem Biophys Res Commun. 1984;122(3):1131-5.<br>
Weiner HL, Frenkel D. Immunology and immunotherapy of Alzheimer's disease. Nat Rev Immunol. 2006;6(5):404-16.<br>
First Aid 2014 page 90 (Down Syndrome); First Aid 2014 page 483 (Alzheimer's disease)
|RightAnswer=A
|RightAnswer=A
|WBRKeyword=Down syndrome, Mental retardation, Retardation, Intellectual disability, Neurodegeneration, Alzheimer's disease, Alzheimer, Dementia, Alzheimer disease, Cognitive, Cognitive decline
|WBRKeyword=Down syndrome, Mental retardation, Retardation, Intellectual disability, Neurodegeneration, Alzheimer's disease, Alzheimer, Dementia, Alzheimer disease, Cognitive, Cognitive decline, Tau protein, Tau, APP, Amyloid, Amyloidosis, Amyloid precursor protein, Neuropathology, Brain, Neurofibrillary tangles, Chromosome, Memory, Memory loss
|Approved=No
|Approved=Yes
}}
}}

Latest revision as of 23:31, 27 October 2020
Author [[PageAuthor::Yazan Daaboul, M.D. (Reviewed by William J Gibson)]]
Exam Type ExamType::USMLE Step 1
Main Category MainCategory::Pathology
Sub Category SubCategory::Neurology
Prompt [[Prompt::A 41-year-old man with Down syndrome is brought to the family's physician for cognitive decline. The family reports that the patient’s memory has been deteriorating for the past year. He cannot recall the names of his brothers and sisters and often has difficulty finding words. He is unable to find his way back home and gets lost when a member of his family does not assist him. Which of the following neuropathologic changes is most likely present in this patient?]]
Answer A AnswerA::Neurofibrillary tangles
Answer A Explanation [[AnswerAExp::Neurofibrillary tangles are abnormal aggregates of proteins within neurons of patients with Alzheimer's disease. Patient’s with Down syndrome have a high risk of developing Alzheimer’s disease at an early age due to increased gene dosage of the amyloid precursor protein (APP) on chromosome 21.]]
Answer B AnswerB::Pick bodies
Answer B Explanation [[AnswerBExp::Pick bodies are silver-staining, spherical aggregations of tau protein in neurons that are associated with Pick's disease, a subtype of frontotemporal lobar degeneration. While Pick’s disease is characterized by memory loss, it is distinguished from Alzheimer's disease by severe mood and personality changes.]]
Answer C AnswerC::Negri bodies
Answer C Explanation [[AnswerCExp::Negri bodies are eosinophilic, sharply-outlined inclusion bodies in neurons of patients with rabies virus. Rabies virus is usually transmitted by an animal bite; it causes acute encephalitis and death among patients who develop symptoms.]]
Answer D AnswerD::Lewy bodies
Answer D Explanation [[AnswerDExp::Lewy bodies are abnormal aggregates of alpha-synuclein protein that develop in neurons. The most common disease associated with the presence of Lewy bodies is Parkinson's disease. Lewy bodies are also present in neurons of patients with Lewy body dementia, a subtype of dementia characterized by symptoms of dementia followed by early parkinsonism (early disability and falls within 1 year of symptoms, in contrast to late disability in parkinson's disease), hallucinations (visual mostly, in contrast to schizophrenia-associated auditory hallucinations), and neuroleptic sensitivity.]]
Answer E AnswerE::Spongioform changes
Answer E Explanation [[AnswerEExp::Spongioform change in the gray matter is the pathological hallmark of Creutzfeldt-Jakob disease. It is characterized by a "spongy appearance" of the cerebral cortex due to the presence of many round vacuoles.]]
Right Answer RightAnswer::A
Explanation [[Explanation::This patient is most likely diagnosed with Alzheimer's disease. Although Alzheimer's disease is most commonly diagnosed in the elderly, patients with Down syndrome are at high risk of developing Alzheimer’s disease at an early age. The presence of an extra chromosome 21 is thought to result in a significant increase in the synthesis of amyloid precursor proteins (APP) that are encoded by chromosome 21. Subsequently, the increase in the amyloidogenic parts leads to early-onset senile plaque formation and Alzheimer's disease. The disease is characterized by the presence of diffuse cortical atrophy with a decrease in acetylcholine (Ach) neutrotransmitter concentration in the brain. Neurofibrillary tangles (shown below) are abnormal proteins present in neurons of patients with Alzheimer's disease. These tangles are formed by hyperphosphorylation of the tau protein, a microtubule-associated protein that causes the tangles to aggregate in an insoluble form. In addition to alterations in APP protein, other proteins are also associated with either early-onset Alzheimer's disease (such as presinilin-1 protein [chromosome 14] and presenilin-2 protein [chromosome 1]) or late-onset Alzheimer's disease (such as ApoE4 [chromosome 19]). On the other hand, ApoE2 protein [chromosome 19] is considered protective against Alzheimer's disease.


Neurofibrillary tangle (red arrow)
Educational Objective: Neurofibrillary tangles are pathological protein aggregates found within neurons in cases of Alzheimer's disease.
References: Lott IT, Head E. Down syndrome and Alzheimer's disease: a link between development and aging. Ment Retard Dev Disabil Res Rev. 2001;7(3):172-8.
Glenner GG, Wong CW. Alzheimer's disease and Down's syndrome: sharing of a unique cerebrovascular amyloid fibril protein. Biochem Biophys Res Commun. 1984;122(3):1131-5.
Weiner HL, Frenkel D. Immunology and immunotherapy of Alzheimer's disease. Nat Rev Immunol. 2006;6(5):404-16.
First Aid 2014 page 90 (Down Syndrome); First Aid 2014 page 483 (Alzheimer's disease)]]

Approved Approved::Yes
Keyword WBRKeyword::Down syndrome, WBRKeyword::Mental retardation, WBRKeyword::Retardation, WBRKeyword::Intellectual disability, WBRKeyword::Neurodegeneration, WBRKeyword::Alzheimer's disease, WBRKeyword::Alzheimer, WBRKeyword::Dementia, WBRKeyword::Alzheimer disease, WBRKeyword::Cognitive, WBRKeyword::Cognitive decline, WBRKeyword::Tau protein, WBRKeyword::Tau, WBRKeyword::APP, WBRKeyword::Amyloid, WBRKeyword::Amyloidosis, WBRKeyword::Amyloid precursor protein, WBRKeyword::Neuropathology, WBRKeyword::Brain, WBRKeyword::Neurofibrillary tangles, WBRKeyword::Chromosome, WBRKeyword::Memory, WBRKeyword::Memory loss
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