Atypical Sex Chromosomes

Question 1

What is Klinefelter’s syndrome?

Answer 1

• 1 in 600 males, have an additional X chromosome (XXY). - 10% of cases identified prenatally however though 2/3 who have it are not aware of it - Diagnosis often comes about accidentally via medical examination for unrelated condition

Question 2

What are the physical characteristics of Klinefelter’s syndrome?

Answer 2

• reduced body hair
• breast development at puberty (gynaecomastia)
• softening or rounding of body contours
• gangly limbs
• undeveloped genitals
• problems with co-ordination and general clumsiness.
• susceptible to health problem usually females (breast cancer)

Question 3

What are the psychological characteristics of Klinefelter’s syndrome?

Answer 3

• Poorly developed language skills/reading ability
• Passive and shy
• Lack interest in sexual activity
• Don’t respond well to stressful situations
• Problems with ‘executive functions’ e.g memory

Question 4

What is Turner’s syndrome?

Answer 4

• 1 in 5000 females, XO chromosomes, affected individuals have 45 chromosomes instead of 46

Question 5

What are the physical characteristics of Turners?

Answer 5

• No menstrual cycle
• Ovaries do not develop (infertile)
• Do not develop breast at puberty ‘shield’ chest
• Low set ears
• ‘Webbed neck’
• high waist to hip ratio (hips not much bigger than waist)
• physically immature tend to retain appearance of prepubescent girls

Question 6

What are the Psychological characteristics of Turner’s syndrome?

Answer 6

• Higher than average reading ability
• Lower than average ability on spatial, visual and memory tasks
• Socially immature (trouble relating to peers)

Question 7

How does this contribute to the nature-nurture debate?

Answer 7

• by comparing with chromosome-typical individuals you can see differences between the two groups so it might be logically inferred that these differences have a biological basis and are a direct result of atypical chromosomal structure
• ‘nature’ influences have a strong influence on behaviour

Question 8

How is it risky to jump to conclusions?

Answer 8

• Differences in behaviour in the syndromes are not causal. May be environmental causes e.g boys are bullied based on appearance and so become shy and passive or because girls with turners look immature they may be treated like children explaining learning problem

Question 9

How has this research helped in the real world?

Answer 9

• leads to earlier and more accurate diagnosis, Australian study of 87 with Klinefelter’s syndrome showed that those who has been identified and treated from a young age experienced significant benefits compared to those to those in early adulthood