atypical sex chromosome patterns

Question 1

Klinefelter’s syndrome

Answer 1

• affects 1 in 600 males (structure is XXY)
• 10% of cases are identified through prenatal diagnosis
• happens usually accidentally medical exams of other conditions
• 2/3 men are unaware that they have it

Question 2

Klinefelter’s syndrome: physical characteristics

Answer 2

• reduced body hair
• breast development around puberty
• softening or rounding body contours
• long ‘gangly’ limbs
• underdeveloped genitals
• coordination problems or clumsiness
• susceptible to health problems more common in females (breast cancer)

Question 3

Klinefelter’s syndrome: psychological characteristics

Answer 3

linked to:
- poor developed language skills
- poorly developed reading ability
- passive & shy
- lack interest of sexual activity
- not responding to stressful situations well
- problems with memory & problem solving

Question 4

Klinefelter’s syndrome: treatments

Answer 4

• testosterone replacement therapy : helps increase hormone levels to normal range
• help produce bigger muscles, depends voice & stimulate hair growth
• fertility treatment

Question 5

Turner’s syndrome

Answer 5

• female genetic disorder
• affects in 2000 girls
• one X chromosome (XO structure)
• randomly happens when a baby is conceived

Question 6

Turner’s syndrome: physical characteristics

Answer 6

• no menstrual cycle ( ovaries fail to develop)
• infertility
• don’t develop breast in puberty & have broad ‘shield’ chest
• low set ears & webbed neck
• hips not much bigger than the waist
• physically immature body (pre-pubescent)

Question 7

Turner’s syndrome: psychological characteristics

Answer 7

• higher thn average reading ability
• performance on spatial, visual memory & math tasks is lower than normal
• socially immature
• have trouble relating to peers & ‘fitting in’

Question 8

Turner’s syndrome: treatments

Answer 8

• growth hormone injections are beneficial in early childhood for some ( can increase adult height)
• oestrogen replacement therapy started at puberty to start breast development
• oestrogen & progesterone given later to begin menstruation & keep womb healthy

Question 9

AO3: contribution to nature-nurture debate (s)

Answer 9

• studies contribute to our understanding of the debate
• can compare them to typical chromosome patterns ( can see psychological & behavioural differences)
• e.g: those with Turner’s have high verbal ability & talk more than typical girls
• differences are due to biology & direct result of abnormal chromosomal structure
• suggests that nature influences behaviour

Question 10

AO3: sampling issue (s)

Answer 10

• to identify characteristics of XXY & XO individuals they need to identify a large sample & build a database
• get an idea of range of characteristics from mild to severe
• only 1/3 with Klinefelter’s have been diagnosed & are the subject of research
• Baoada et al: report that studies following children from birth have produced more accurate pictures
  
  • many don’t report cognitive/ psychological problems
  • many are highly successful in their academic & personal lives
• suggests that typical picture may be exaggerated

Question 11

AO3: environmental explanations (w)

Answer 11

• psycholgical & behavioural differences in those with Turner’s is due to environmental & social influences & not biology
  
  • those with with Turner’s are socially immature as they have been treated ‘immaturely’ by those around
• may raect to pre-pubescent appearance in a way which encourages immaturity & affects performance at school ( causes developmental problems identified)
• can’t assume differences are due to nature

Question 12

AO3: real-world application (S)

Answer 12

• continued research will lead to earlier & more accurate diagnoses & more positive outcomes for individuals
• Australian study : 87 people with Klinefelter’s showed that those identified & treated from a young age had significant benefits that those diagnosed in adulthood
• increased awareness allows practical application

Question 13

AO3: knowing or not knowing (S & W)

Answer 13

• many are unaware that they have Klinefelter’s or Turner’s
• may be good as it avoids sel-fullfilling prophecy
• knowing you have it may help someone understand why they feel or look different & that their behaviours aren’t their fault
• they gain access to medical & psychological treatment & support