Atypical Chromosome Patterns

Question 1

How many males does Klinefelter’s syndrome affect?

Answer 1

1 in 600

Question 2

Who does Klinefelter’s syndrome affect?

Answer 2

Biological males with the anatomy and appearance of a male but with an extra X chromosome.

Question 3

Sex chromosome structure of Klinefelter’s syndrome

Answer 3

XXY

Question 4

How many Klinefelter’s are identified by prenatal diagnosis?

Answer 4

10%

Question 5

How many Klinefelter’s syndrome cases come about accidentally?

Answer 5

2/3

Question 6

Physical characteristics of Klinefelter’s syndrome

Answer 6

• Reduced body hair
• Breast development at puberty
• Softening or rounding of body contours
• Clumsiness
• Susceptible to health problems often found in women e.g. breast cancer

Question 7

Psychological characteristics of Klinefelter’s syndrome

Answer 7

• Poorly developed language and reading skills
• Passive, shy, lacking interest in sexual activity
• Responding badly to stressful situations
• Problems with executive functions e.g. memory

Question 8

How many women does Turner’s syndrome affect?

Answer 8

1 in 5000 females

Question 9

What is Turner’s syndrome?

Answer 9

An absence of an X chromosome

Question 10

What is the sex chromosome structure of females with Turner’s syndrome?

Answer 10

XO

Question 11

How many chromosomes do females with Turner’s syndrome have?

Answer 11

45 instead of 46

Question 12

Physical characteristics of women with Turner’s syndrome

Answer 12

• No menstrual cycle - the ovaries don’t develop and so women are sterile
• Broad ‘shield’ chest - don’t develop breast
• Low set ears
• Webbed neck
• High waist to hip ratio
• Physically immature - retain the look of pre-pubescent girls

Question 13

Psychological characteristics of Turner’s syndrome

Answer 13

• Higher than average reading ability.
• Performance on spatial, visual memory and mathematical tasks is lower than normal
• Socially immature - ‘hard to fit in’

Question 14

Gives insight into the nature nurture debate

Answer 14

• Comparing people with these characteristics to chromosome - typical people makes it possible to see psychological and behavioural differences.
• Therefore it may be logically inferred that these differences have a biological basis and are a direct result of abnormal chromosome structure.
• This supports the view that innate ‘nature’ influences have a powerful effect on psychology and behaviour.

Question 15

(Nature - nurture evaluation) However relationships between chromosomal abnormalities and differences isn’t casual

Answer 15

• However it could be that environmental and social differences are more responsible for the behavioural differences observed.
• Social immaturity seen in women with Turner’s syndrome could be due to the fact that people treat them immaturely.
• Therefore it could be wrong to assume psychological and behavioural characteristics of people with atypical sex chromosome patterns may be due to nature and rather may be due to nurture.

Question 16

Real world application

Answer 16

• Research into atypical sex chromosomes patterns s likely to lead to earlier and more accurate diagnosis.
• Herlihy eat al - study of 87 individuals with Klinefelter’s syndrome showed those diagnosed and treated from a young age experienced benefits in terms of managing their condition.
• Increased awareness can have positive outcomes in the future.

Question 17

Sampling issue

Answer 17

• To identify characteristics its necessary to identify a large number of individuals with the disorder and build a database so we can see the full range of characteristics from mild to severe.
• However most symptoms of Klinefelter’s syndrome are only identified when severe.
• Richard Boda et al produced a more accurate picture of the characteristics - Highly successful academically and in their lives and careers.
• Therefore the typical picture of Klinefelter’s may be distorted.