Genetic/Biological Explanation for Anorexia TEST ON EVAL MONDAY

Question 1

Genetic Explanation for Anorexia

4

Answer 1

EPHX2 Gene

ITPR3 Gene

Strober (2000)

Gorwood (2003)

Question 2

EPHX2 Gene

Answer 2

Codes for an enzyme that regulates cholesterol metabolism.

Van Zeeland found EPHX2 is linked with AN

Question 3

ITPR3 Gene

Answer 3

Encodes an enzyme involved in detecting taste.

Question 4

Strober (2000)

Answer 4

Found that AN was rare in relatives of those who had never had an eating disorder. It was 11.3x more prevalent in those who had

Question 5

Gorwood (2003)

Answer 5

Estimated heritability of AN was 70%

Question 6

Dopamine & AN

Answer 6

Mutation in the DAT1 gene disrupts dopamine levels, leaving v high levels of dopamine. This desensitized reward systems, thus the normal rewarding function of eating is limited (Avena & Bocarsly 2012)

Question 7

Serotonin & AN

Answer 7

5-HTR2A gene mutations affect seratonin binding to receptors. Kaye (2005). Appetite-related neural info is thus not processed correctly

Question 8

Eval. of Bio/Genetic explanation for AN

1 Strength, 2 Weaknesses

Answer 8

Strength
- Holland et al. (1988) studied 45 female twins,
found concordance rates of 56% MZ and 5% DZ. Replicated by Holland & Treasure (1995) and similar results found
- Strober (2000) found AN 11.3x more prevalent in those w family members w history of eating disorders
- Gorwood (2003) estimated AN heritability at 70%

Weaknesses

• Depend on Equal environments assumption. Joseph (2002) argues MZ twins are treated more similarly than DZ.
• Wide variety of AN symptoms can’t be explained by one gene as there are so many physical, cognitive & behavioural symptoms. AN is polygenic. Oversimplified and reductionist