Schizophrenia - Bio Part 2

Question 1

Schizophrenia being heritable

Answer 1

Schizophrenia is actually a heritable conditon with yhe heritability being 79%
Suggests large factors for genetic factors in determining the disorder

Question 2

Genetic mutations

Answer 2

There are as many as 700 genes that are responsible for schizophrenia

One way of schizophrenia being inherited can be through the absence of a family histry of the disorder, if genes are deleted or duplication of DNA strands
E.g digeorge syndrome is caused by the deletion of 30-40 genes in a specific area beinf deleted from chromosome 22, as many as 25% then can inherit schizophrenia from this

Question 3

Candidate genes

Answer 3

Specific genes have been identified that are linked to schizophrenia.
COMT gene- link between digeorge syndrome + deletion of COMT gene
, this comt gene provides jnstructions for an enzyme that breaks down dopamine in prefrontal cortex- deletion of this would result in dopamine levels beinf unregulated - schizophrenia

DISC1 gene-people with abnormality of DISC-1 are likely to end up gaining schizophrenia due to this gene coding for GABA, which is a neurotransmitter that regulates other neurotransmitters such dopamine and glutamate

Question 4

Rosenthals diathesis stress model

Answer 4

Genes cause a predisposition for schizophrenia rather than causing it, the genes would be present but would require a “stress” (biological/environmental factor) to then trigger it.

Environmental stressors can even change the way genes are even expeessed therefore genetic vulnerabilities can be “switched on” because of environmental events.

Question 5

Schizophrenia runs in families?

Answer 5

Irving gottesman, found a concordence rates for thouse of different genetic similarity and identified a 42% concordence rate between MZ( identical twins) and 9% for DZ( non identical twins) twins, signifies that biology plays a major part

-however a weakness to this, is a diathesis stress model, mz show more genetic sinilarity but would also be treated similarly becauee they look more similar and are always the same sex, the highef likely chance of schizophrenia could just be due to environmental similarity - diathesis stress model

Question 6

Application

Answer 6

Genetic counselling
Strength- can be used to inform genetic counselling, when a family member receives diagnosis of schizophrenia, the family may want ore information about wether the condition can be inherited