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GENETIC INFLUENCES (Search for genes: with association studies…
GENETIC INFLUENCES
For general cognitive abilities
IQ heritability 50% in Y e 80% in middle adulthood
Heritability in late life declines and environmental variance increases
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Genetic influences on change are shared across domains. There's a specific genetic variance on change only for memory and spatial ability
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Rearing environment (ambiente di allevamenti) has a little impact on cognitive functions in the second half of lifespan
Factors:
- education
- socioeconomical status
- occupational complexity
- lung function (polmonare)
- leisure activities
- social partecipation
These are genetically influenced.
- Education genetic variance on performance level but environmental variance in rate of change
- lung function genetic e environmental variance with decline in fluid intelligence
Physical context
Physiological: obesity, cardiovascular health, lung function
Body mass index (BMI)
- normal (19-25 kg/m2) related to better health e survival
- elevated (25-30) in late adulthood related with better health than normal BMI -Obesity paradox
- heritability constant at 70%
Blood pressure BP
- moderate genetic influences. heritability for systolic 45%, for diastolic 34%
- decreasing genetic factors with age
- heritabilty for elevaterìd BP on 46-63%
- environmental influences are caffeine, smoking, BMI, medications
Genetic infliuences on
- serum lipids (cholesterol) on 30-80% and
- lung function 30-50%
Behavioral physical: muscle, strength, functional ability
Physical strength
- in adulthood heritability on 30-60%
- heritability for physical functioning in ecological setting
Functional ability
- relationship between genetic influences on lung function and genetic influences on measure on fluid intelligence
- genetic variance in lung function can predicts variance in cognitive function after 6 yr
- correlaation between BMI and at midlife and cognitive scores in late life
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Search for genes: with association studies (correlational relationship) or linkage strategies (trace within families)
The most studied gene is Apolipoprotein E (APOE) and SORL1:
- APOE role in lipid metabolism pathway
- SORL1 implicated in normative cognitive aging
- link between cognition and physical traits
Apoe is a product of atrocytes. It brings cholesterol to neurons.
It has 3 alleles: Apoe E2, E3, E4
- E2 7% correlate with PD
- E3 normal 79%
- E4 14% correlate with AD, hippocampal shrinkage, SLA, cognitive deficits, Telomeres shortening, cerebrovascular desease, HIV
Apoe E4 is associated with incresed beta-amyloid (A B) protein deposition (hallmark of AD). This deposition is also observed in non normal aging.
SORL1
- role in protein sorting and binding to low density lipoprotein
- transport of amyloid precursor APP
PRRC1 on chromosome 5 is important in fluid ability performance in late adulthood and its alteration in observed in temporal cortical regions
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Other genes: BP, serum lipid profiles e heart rate
Telomeres are the end of chromosomes
They shorten after every cell division
telomeric loss associated with risk of somatic mutation and damage
Shorten telomeres are predicted by increasing age, low education, illness, social stresss and adversity
Telomere lenghts are heritable
Longer telomere lengths correlate with higher working and ep memory performance
- In high physical activity people with apoe4 show comparable activation to those without the risk
- apoe4 people can't surpass not-apoe4 individuals in positive outcome