Genetic Explanation of Schizophrenia Flashcards
What did Hilker (2018) find
79% herritability
What did Wright (2014) find
700 genes identified correlated with schizophrenia
What syndrome was linked with schizophrenia
Di George Syndrome
How does Di George Syndrome make you more likely to have schizophrenia
Syndrome caused by deletion of 30-40 genes on chromosome 22
Making you 25% more likely
What is the COMT gene
Link between DiGeorge Syndrome and schizophrenia
Deletion of COMT gene created poor regulation of dopamine levels = schizophrenia
What is a candidate gene
Gene linked to schizophrenia
Name the two genes that could be responsible for causing schizophrenia
COMT gene
DISC1 gene
How does the DISC1 gene relate to schizophrenia (how like you are to get it)
Abnormality of gene makes you 1.4x more likely to develop schizophrenia
What does DISC1 gene do
Codes for GABA, regulated glutamate and dopamine in the limbic system
So, how does the DISC1 gene make you more likely to be schizophrenic
Codes for GABA (gaba regulates glutamine and dopamine)
Studies have found a link between dopamine and gaba with schizophrenia
What does the Diathesis-stress model state
Genes more likely to create a vulnerability to schizophrenia
Schizophrenia gene must be triggered by environmental factors
Bad environment + DISC1 gene = schizophrenia
Study supporting claim
Gottesman (1991)
What did Gottesman (1991) do and found in results
Looked a correlation between DNA and schizophrenia
Found:
Concordance rate of 48% in MZ twins and 17% in DZ twins
Clearly a genetic component to schizophrenia
What does the concordance rate mean in this case
If one MZ twin had schizophrenia, the other twin has a 48% chance of getting it
Weakness study
MZ twins was only 48%, if it was purely genetic it would be 100%
So, there is an environmental factor involved in making an individual schizophrenic
Other explanation study name
Dahoun et al (2017)
What did Dahoun et al (2017) find
DISC1 associated with presynaptic dopamine dysregulation
Other explanation study name (2)
Egan et al (2011)
What did Egan et al (2011) find
Link between decreased dopamine activity in prefrontal cortex and one form of COMT gene - Val allele shows genetic variations underpin neuroschemical differences
Is this a testable study
Very testable
You can compare DNA with two individuals and see if you are more likely to get it when someone related to you had schizophernia
Usefulness of study
Family members receive diagnosis of schizophrenia, family can learn more about inheritability
Recurrence risk is calculated and family can interpret information
Help support families from fears about developing schizophrenia if it is in their family
Simplicity of study
Complex theory
Wright found there were 700 genes that are associated with schizophrenia
Hard to draw conclusions as there are so many different genes
