Atypical Sex Chromosome Patterns

Question 1

Klinefelter’s Syndrome

Answer 1

• Individuals are born as biological males with an (47) XXY chromosomal structure instead of (46) XY.
• 1 in 500 and 1 in 1000 people contract the condition.
• Testes do not function properly and produce less testosterone.

Question 2

common physical features of Kilnefelter syndrome

Answer 2

• Reduced fertility,
• Taller than expected
• Lower muscle tone
• Less facial hell
• Gynecomastia
• Low mood and anxiety
• Low energy levels
• Social difficulties.

Question 3

• Common psychological features: of Klinefelter syndrome

Answer 3

• Poorly developed language skills and reading ability.
• Passive, shy and lack interest in sexual activity.
• React badly to stress.
• Struggle with ‘executive functions’ like memory and problem solving.

Question 4

Health issues related to Klinefel;ter syndrome

Answer 4

• Higher risk of weak bones, type 2 diabetes, auto-immune disorders, breast cancer and heart diseases.
• Tests include blood tests and fertility tests to check testosterone levels and sperm count.
• Treatments include testosterone replacement by gels, tablets of injections. Others are speech therapy, educational and behavioural support, fertility treatment and physiotherapy.

Question 5

Turner’s Syndrome

Answer 5

• Genetic condition that only affects girls.
• 1 in 5000 girls will contract the condition.
• Missing an X chromosome, so instead of (46) XX, it is (45) X

Question 6

• Physical features: turner syndrome

Answer 6

• Absence of menstrual cycle.
• Ovaries do not develop properly so are sterile.
• No breast development at puberty.
• Low sets ears and webbed neck.
• Physically immature.

Question 7

• Cognitive features: turneer syndrome

Answer 7

• High reading ability (above average).
• Spatial, visual, and mathematical abilities are lower.
• Socially immature and trouble relating to peers.

Question 8

Health related to turner syndrome

Answer 8

• Diagnosis is post-birth.
• Weaker bones, hearing difficulty, problems with heart, liver, and thyroid gland.
• Hormone treatments can be used to promote oestrogen and progesterone production.
• Infertility is common.

Question 9

Evaluation

Nature-Nurture Debate

Answer 9

• Contributes to the nature and nurture debate.
• By comparing people who have these syndromes with chromosome-typical individuals it becomes possible to see psychological and behavioural differences between two groups.
• It may be logically inferred that these differences have a biological basis and are a direct result of the abnormal chromosomal structure.
• This supports the view that the innate ‘nature’ influences have a powerful effect on psychology and behaviour.

Question 10

counterpoint for the nature unturned debate

Answer 10

• However, there are issues in leaping to these conclusions.
• The relationship between the atypical chromosomal patterns and the symptoms of these syndromes is not causal, it may be purely a correlation.
• E.g., social immaturity in Turner’s syndrome may be due to social factors such as immature treatment rather than genetics.
• This shows that it could be wrong to assume that phenotypical differences in people with atypical sex chromosome patterns are due to nature.

Question 11

real world application

Answer 11

• Application to managing the syndromes.
• Continues research into patterns leads to earlier and more accurate diagnosis of syndromes and future outcomes.
• Herlihy et al. (2011): 87 individuals with Klinefelter’s showed those who had been identified and treated from a young age better managed their symptoms compared to those diagnosed in adulthood.
• Suggests that increased awareness of atypical chromosome patterns does have useful real-world application.

Question 12

Sampling Issue

Answer 12

• One limitation is there may be a sampling issue.
• To identify the characteristics of Klinefelter’s syndrome it would be advised to build a database of people who have the condition with symptoms ranging from severe to mild.
• Only extreme cases have been identified and therefore the picture of typical symptoms may be distorted.
• Boada et al. (2009) report that studies that follow XXY individuals from birth produce a more accurate picture of the characteristics – many people with Klinefelter’s do not experience large cognitive/psychological symptoms and many have academic success and personal achievement.
• This suggests the picture of Klinefelter’s and Turners may be exaggerated.