Anorexia nervosa: One biological explanation

Question 1

What is the role of EPH gene and how does it link to AN?

2

Answer 1

• Codes for enzyme = regulates cholesterol metabolism

- Acute stages of AN = v high cholesterol lvls

Question 2

What did Zeeland et al. do and suggest?

2

Answer 2

• Sequenced 152 candidate genes of AN/ctrl ppt

- Inherited variant of EPH = overactivity of epoxide hydrolase, disrupting metabolism of cholesterol

Question 3

What is the role of ITP gene and how does it link to AN?

2

Answer 3

• Encodes protein (receptor for inositol, involved in detecting tastes e.g. sweet/bitter)
• Genetic dysfunction of taste pathway, AN = indifferent to tastes that others enjoy (>motivation)

Question 4

What is the role of DAT1 gene?

2

Answer 4

• Codes for dopa transporter

- Regulates transport of dopa between neuron and synaptic cleft (reuptake)

Question 5

What is the role of 5-HTR gene?

2

Answer 5

• Codes for subtype of postsynaptic sero receptor

- 2A receptor = most implicated in AN

Question 6

What would a mutation of 5-HTR gene cause and how does this link to AN?
2

Answer 6

• Affects structure of 2A receptor, >binding of sero

- Appetite neural info not transmitted normal

Question 7

Evaluate genes as an explanation of AN

3

Answer 7

Holland et al. studied pairs of female twins, found concordance rates of 56% for MZ’s and 5% (DZ). Replicated by Treasure et al. confirming earlier findings (MZ concordance = 65%, 32% DZ)

Using j genes doesn’t take interactionist approach. Not holistic, AN is polygenic. Genes contribute to symp of AN to diff degrees. ^Complex, reductionist

Abraham note genes = create diathesis to AN that’s only expressed when individual tries to lose weight (stressor). Diathesis (genes) = ^vulnerable to disordered eating.