AN and genes

Question 1

what evidence is used to explain genes and AN?

Answer 1

family studies and twin studies

Question 2

EPHX2 gene

Answer 2

• codes for an enzyme which regulates cholesterol metabolism
• such metabolism also has links to serotonin, which we know is associated with anxiety and depression when levels are low.
• it also has links to the hypothalamus which regulates the feeling of hunger and the amygdala which regulates fear response.
• hence the irregularities in the expression of this gene may account for symptoms such as fear around food.

Question 3

ITPR3 gene

Answer 3

• codes for a protein involved in detecting the taste of food, such as bitter and sweet.
• if this gene is faulty in those with AN it could mean they are unable to use taste as a motivator to eat.

Question 4

DAT1 gene

Answer 4

• has been linked to the function of dopamine on the reward system.
• if this gene is mutated this can mean dopamine activity is disrupted, resulting in lack of motivation an satisfaction others would normally get after eating.

Question 5

Kipman et al 1999
(evidence from twin studies)

Answer 5

• looked at many twin studies involving AN and produced a heritability estimate of 71%

Question 6

family studies

Answer 6

• AN has been shown to run in families
• Family studies look at first degree relatives of people with and without diagnosed eating disorders.
• the estimated heritability rate of AN is 70%

Question 7

Nisoli et al 2007
(evidence from family studies)

Answer 7

• established that in a group over 100+ Italian ppts suffering from AN, bulimia, obesity that a gene previously associated with other psychopathologies such as alcohol and drug abuse, the TaqA1 allele, that is located at a specific position on a specific chromosome.
• these DNA codings determine distinct traits that can be passed on, is present in those vulnerable to eating disorders.