Behavioral Science - Genetics in Psychiatry - Thomas L. Schwartz Flashcards
T/F – Genetics of most hereditary disorders (70 % inheritance) can be mapped to specific genes
False.
require hundreds of mutated genes to produce spectrum of clinical symptoms that would cause someone to meet diagnostic criteria for specific disorder
High or low genetic heritability? ADHD? Depression? Anxiety? Schizophenia?
ADHD? - HIGH
Depression - LOW
Anxiety - LOW
Schizophenia - HIGH
Epistasis describes ___
the effect of one gene being dependent on the presence of one or more ‘modifier genes’
What are epigenetics? Does it involve changes in DNA?
describes change in gene expression due to environmental influences, NOT change DNA
Nigrostriatal dopamine pathway:
Originates ___ projects to ____
Controls ___
Originates at substantia nigra
Projects to striatum/basal ganglia
Controls motor function and movement
Mesolimbic dopamine pathway:
Originates ___ projects to ____
Controls ___
Originates at VTA of midbrain
Projects to nucleus accumbens
Controls reward and perception of pleasurable sensations, delusions and hallucinations of psychosis
Mesocortical dopamine pathway:
Originates ___ projects to ____
Controls ___
Originates at VTA of midbrain
Projects to DLPFC or VMPFC
Controls executive functions
VTA > DLPFC Controls cognitive symptoms of schizo
VTA > VMPFC controls affective symptoms of schizo
Tuberoinfundibular dopamine pathway:
Originates ___ projects to ____
Controls ___
Originates at hypothalamus
Projects to anterior pituitary
Controls prolactin secretion
Tuberoinfandibular DA pathway
hypofunction?
hyperfunction?
hypofunction? hyperprolactinemia
hyperfunction? hypoprolactinemia
Mesolimbic dopamine pathway:
hypofunction?
hyperfunction?
hypofunction? amotivation, apathy
hyperfunction? addiction, hallucinations
Nigrostriatal dopamine pathway:
hypofunction?
hyperfunction?
hypofunction? dyskinetic movement, parkinsonism
hyperfunction? dyskinetic movement
Mesocortical dopamine pathway:
hypofunction?
hyperfunction?
hypofunction? inattention
hyperfunction? hypervigilance, insomnia
Which dopamine pathways are involved in schizophrenia? Which are hypoactive which are hyperactive?
Mesolimbic - hyperactive
Mesocortical - hypoactive
What could a mutation in COMT cause?
Schizophrenia ** if paired with other mutations
COMT is catachol-O-methyl transferase > degrades DA mutation usually generates high levels of DA
What are 4 genes involved in dopamine pathways that could lead to schizophrenia symptoms if many mutations occur?
COMT
Tyrosine hydroxylase
D2R (dopamine receptor 2 - sometimes called DAR2)
D3R
What does DISC1 do?
Mutation of DISC1 is associated with what disease?
What is the MAO
DISC1 normally facilitates neurogenesis, cell migration, differentiation, synaptogenesiss and selective pruning of synapses
schizophrenia
epistatic mutation - multiple other downstream genes are affected
What are 2 genes that DISC1 mutation can affect?
ErbB4, NRG
Mutation of DISC1 is associated with what disease?
What is the MAO
schizophrenia
epistatic mutation - multiple other downstream genes are affected
T/F it is possible to have normal dopamine levels and still have schizophrenia
True
Can be due to disrupted neurodevelopment that doesn’t affect dopamine
characteristic brain activity patterns on fMRI associated with gene activation/deactivation/mutation
endophenotype
What is one plausible explanations for mesocortical hypoactivity and mesolimbic hyperactivity?
dysfunctional PFC results in loss of top down control of limbic DA release
Hyperactive mesolimbic system is associated with mutations in which genes?
D2R, Tyrosine hydroxylase, MAOs
Hypoactive mesocortical system is associated with mutations in which genes?
COMT and D3R
What are 2 genes involved in ADHD
D4R, D5R