Most common form of dementia in elderly. Clinically characterised by gradual, progressive decline in intellectual function such as defecits of recent memory, language, visuospation and attention.
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Common symptoms of AD? (4)
Psychosis. Depression. Agitation and Anxiety.
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Physical changes seen in brain in AD patients? (4)
Cortical shrinkage. Enlarged ventricles. Shrinking hippocampus. Huge neuronal and dendritic loss in temporal, parietal and entorhinal cortex, the hippocampus and amygdala.
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What is the result of this extensive neuronal and dendritic loss? (1)
Decreased activity of enzymes; mainly choline acetyltransferase.
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3 physiological effects of AD? (3)
Formation of Beta-Amyloid plaques. Tangling of Tau proteins. Micro-tubules of neuronal axons disintegrate.
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What is B-Amyloid? (4)
Amyloid is a general term for protein fragments that the body produces normally. Beta amyloid is a fragment of a protein snipped from another protein called amyloid precursor protein (APP). In AD the fragments accumulate to form hard insoluble plaque
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Two main types of AD? (4)
Late Onset (AD2) and Early Onset (AD1, AD3 and AD4)
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What is early onset AD? (1)
Refers to AD cases in families in which multiple cases of AD occur with the mean age of onset before 65; usually 40-50.
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3 gene mutations identified in presenile AD? (3)
B-amyloid precursoer protein gene.(APP)(AD1). Presenilin-1 and Presenilin-2 (PSEN1(AD3) and PSEN2(AD4))
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Discuss APP mutation. (3)
28 different mutations in APP identified. All located on or near the proteolytic cleavage site involved in generation of B amyloid.
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Discuss PSEN mutations. (2)
Inc production of beta-amyloid 42 peptide. May have deleterious effect on neurons.
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Which protein is linked to late onset AD? (1)
Apolipoprotein E (ApoE4)
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How long is a mature APOE protein? (1)
299 amino acids.
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Main types of APOE? (3)
ApoE2, ApoE3 and ApoE4
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What is the difference? (2)
Coded for by 3 alleles. Isoforms differ in amino acid sequence at 2 sites.
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Which are linked to AD? (4)
ApoE4 is associated with sporadic AD. Risk increases with n.o ApoE4 alleles. ApoE2 may provide protection against AD - more than just absence of E4 allele.
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E4 v E3? (1)
Risk associated of E4 homozygosity is compared to E3 homozygosity.
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In which population are E4 heterozygotes AT RISK? (2)
Caucasian and Hispanics.
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In which gender are E4 heterozygotes AT RISK? (1)
Women have a 2 fold higher risk than heterozygous men.
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Other cards in this set
Card 2
Front
Common symptoms of AD? (4)
Back
Psychosis. Depression. Agitation and Anxiety.
Card 3
Front
Physical changes seen in brain in AD patients? (4)
Back
Card 4
Front
What is the result of this extensive neuronal and dendritic loss? (1)
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