Topic 4 - genetic and endocrinology disorders Flashcards
What is the definition of intellectual disability?
significant limitation in cognitive functioning and the ability to adapt to the demands of everyday living and an onset before the age of 18 years
Down syndrome is caused by …
an extra whole copy or segment of chromosome 21 (giving rise to the syndrome name of trisomy 21).
Phenotype of down syndrome
cognitive impairment, characteristic facial appearance and muscle hypotonia.
Thee models that account for the relationship between genes, brain, and behavior in down syndrome
- critical region model: DS phenotype is the product of a few genes located within the down syndrome critical region
- amplified developmental instability model: the presence of a threshold number of genes leads to DS phenotype
- gene dosage effects model: three copies of series of genes causes a increase in the expression of gene products.
Which behavioral domain is most affected in individuals with DS?
Language
What kind of language is mostly impaired in individuals with DS?
Expressive language becomes increasingly impaired relative to comprehension
In both comprehension and production, vocabulary knowledge is stronger than knowledge of syntax and grammatica
What is the cause of fragile X syndrome
a mutation in the FMR1-gene on the X chromosome
What are the impairments in FXS?
processing of sequential information, auditory short term memory and attention (inhibition and sustained)
Which domains are relatively strong in FXS?
simultaneously processing, Long term memory and social cognition
What are the language problems in FXS?
- vocabulary relatively strong, syntax relatively weak
- pragmatics weak: perseveration big problem
Which two conditions are associated with the premutation of FXS?
- FXTAS: neurodegenerative disorder
- Primary ovarian insufficiency in females
What is the cause of Williams Syndrome (WS)?
hemizygous deletion of 28 genes located on the long arm of chromosome 7
WS is characterized by …
a distinctive pattern of dysmorphic facial features, CVD, growth deficiency, connective tissue abnormalities, increased blood calcium and intellectual disability
What are the weaknesses in WS?
weaknesses in spatial construction, object and face recognition, and the perception of biological motion
In WS, which processing stream appears to be affected?
the dorsal processing stream
Is language affected in WS?
Although language is relatively strong in WS, there are some weaknesses.
Syntax appears to be intact.
People with WS use their relatively strong … to overcome challenges to language learning
verbal working memory
What interruption may help to explain the deficits in spatial processing that define the WS cognitive phenotype?
There is decreased gray matter and sulcal depth in the area of the inferior parietal cortex and it is suggested that these structural abnormalities may provide a roadblock to information traveling along the dorsal processing system
In an intervention effort by individuals with DS, what should be the focus of attention?
expressive syntax and auditory memory
In an intervention effort by individuals with FXS, what should be the focus of attention?
social dimensions of language
In an intervention effort by individuals with WS, what should be the focus of attention?
social dimensions of language and spatial cognition
The sex hormones and corticosteroids influence neuroelectrophysiology, neuroanatomy, and cognition through their interaction with a variety of brain structures, particularly the …
hippocampus
What are the two primary sex hormones?
estrogen and progesterone
Each sex hormone bind to …
estradiol, androgen and aromatase receptors that are located in the brain regions associated with learning and memory, notably, the hippocampus, amygdala and prefrontal cortex
What is the effect of estrogen..
is increases neuronal spine in the hippocampus
What happens after estrogen HRT?
improvements in verbal memory and learning
What is the karyotype and cause of turner syndrome?
X0 -> absence of all or part of one X chromosome
TS is characterized by …
short stature, gonadal dysgenesis, lower estrogen levels, difficulties in nonverbal memory and reasoning, diminished visuomotor and visuospatial skills
TS produces atypical EEG patterns and is related to …
volume reduction predominantly in the right hemispheric brain structures
What are the most common neuropsychological deficits in TS?
Spatial and nonverbal skills, nonverbal memory, visuospatial WM, motor abilities
Androgen supplementation in TS individuals results in ….
improvements in verbal abilities, spatial cognition, executive function and working memory
Testosterone related to …
increased concentration of nerve growth factors in the hippocampus
Dramatic decreases in testosterone is related to impairments in …
visuomotor speed, WM, RT, and sustained attention
Moderate doses of testosterone supplementation are associated with modest improvements in …
verbal and spatial memory
What is the cause and karyotype of Klinefelter Syndrome?
at least one additional X chromosome in phenotypic males -> XXY karyotype
KS boys have …
low basal testosterone levels
The additional X chromosome in KS is related to
infertility, gynecomastia and small testes
Males with KS show altered, or atypical … hemispheric …
left hemispheric lateralization
KS is most associated with difficulties in …
language, attention, EF and motor skills.
Pre-pubertal boys may show deficits in …
Post-pubertal boys may show deficits in …
Pre: sustained attention
Post: language + motor skills
What is the effect following hormonal supplementation in KS boys?
although pubertal effects are related to low testosterone levels, no changes follow hormonal supplementation
What are corticosteroids?
hormones endogenously released by the adrenal cortex upon activation of the ANS
What are the two primary types of corticosteroids?
glucocorticoids and mineralocorticoids
Both glucocorticoids and mineralocorticoids have receptors in the …. and are necessary for ….
hippocampus ; intact encoding for learned material
Elevated levels of glucocorticoids are consistently related to …
hippocampal damage, including neuroanatomical changes in the hippocampus such as loss of hippocampal volume and increased ventricular volume
What is the cause of cushing syndrome?
chronic exposure to excess endogenous glucocorticoids produced by the adrenal cortex
What are the main symptoms of Cushing syndrome?
fatigue, high BP, glucose intolerance
What are neuroanatomical findings in cushing syndrome?
loss of brain volume
What are neuropsychological impairments in cushing syndrome?
verbal memory, learning and IQ
What is the cause of addison disease (primary adrenal insufficiency)
the inability of the adrenal cortex to produce and secrete corticosteroids
What are symptoms of addison disease?
orthostatic hypotension, fatigue and weight loss
What are neuropsychological impairments in addison disease?
spatial memory and learning difficulties
What is the treatment for addison disease and what are the consequences?
Oral glucocorticoids such as prednisone -> improvement of neuropsychological function
Congruent with left hemispheric abnormalities, KS is associated with difficulties primarily in … and secondarily with ..
language
attention and motor skills
Consistent with right hemispheric abnormalities, TS is associated primary with difficulties in … and secondary with …
nonverbal/visual skills, visuomotor and visuospatial skills
working memory and attention
