Williams Flashcards
Phenotype
The physical, behavioral, or cognitive expression of a gene
Velo-Cardio-Facial Syndrome
Microdeletion on chromosome 22; increased risk for psychiatric disorders, including schizophrenia
Turner’s syndrome
Results from partial or complete X-monosomy for women (females only have 1 x chromosome). Although not associated with retardation, increased risk of learning difficulties in terms of mathematical, visuospatial, social behavior.
Visuospatial processing
Parietal cortex - compared to healthy controls, people with Turner’s syndrome have less activity
Fragile X
A disease that affects the X chromosome. Boys are more affected because females have two x chromosomes and can compensate. Most common cause of retardation among boys. Result of too many CGG repeats.
Phenotype of fragile X
Social anxiety, deficit in inhibitory control, impairments in females with episodic memory. Episodic memory relies on hippocampus and both structural and functional abnormalities detected there.
Genetic basis of Williams Syndrome
Deletion on chromosome 7. Removes more than 20 genes that encode for different functions. Results in a number of cognitive, behavioral, and physical phenotypes.
Physical phenotypes of Williams syndrome
Facial characteristics - elastin gene seems to be involved in facial features Growth Dental abnormalities Premature aging Heart problems
Why WS is important
Unlike like conditions such as autism, we know what genes are deleted. Can map specific genes onto behavior, brain, and cognition. Thus can gain an excellent understanding of relationship between those.
Cognitive and social phenotypes in WS
Mental retardation
Hypersocial
Memory loss (lose train of thought
Learning disabilities, especially with dorsal stream visuospatial processing
Overly trusting. Socially overwhelming.
Little concept of time, value of money, age.
Williams dorsal deficits
Dorsal pathway - reduced sulci depth and cortical thickness. Visualspatial deficits: remember drawing the house; arranging blocks.
Williams Memory
Poor delayed memory and learning in both verbal and visuospatial memory.
Perform below average on speeded naming tasks - problems with retrieval
Social fear in Williams
WS showed less activity to fearful faces - less activity in amygdala. Helps explain sociableness.
Relatively preserved neural and cognitive functions
Language, face processing (remember this is in temporal/fusiform face area) and musical skills
Face processing in WS
Fusiform gyrus is typically enlarged in WS