ATYPICAL SEX CHROMOSOME PATTERNS

Question 1

Define Atypical sex chromosome patterns

Answer 1

Any sex chromosome pattern that deviates from the usual XX/XY formation and which tends to be associated with a distinct pattern of physical and psychological
symptoms.

Question 2

Define Klinefelter’s syndrome(2)

Answer 2

• A syndrome affecting males in which an individual’s genotype has an extra X chromosome (in addition to the normal XY),
  
  • characterised by a tall thin physique, small infertile testes, and enlarged breasts.

Question 3

Define turner’s syndrome (2)

Answer 3

• A chromosomal disorder in which affected women have only one X chromosome,
  
  • causing developmental abnormalities and infertility.

Question 4

Explain what klinefelter’s syndrome is (3)

Answer 4

• Individuals who have this condition are biological males - with the anatomical appearance of a male - and have an additional X chromosome. As such, their sex chromosome structure is XXY.
  
  • Although 10% of cases are identified by prenatal diagnosis, it is thought that around two-thirds of people who
    have Klinefelter’s syndrome are not aware of it.
  • Diagnosis often comes about accidentally via a medical examination for some unrelated condition.

Question 5

What are some physical characteristics identified for Klinefelter syndrome (3)

Answer 5

• reduced body hair when compared to a ‘normal’ male.
  
  • There may be some breast development at puberty (gynecomastia)
  • susceptible to health problems that are usually more commonly found in females, such as breast cancer.

Question 6

What are some psychological characteristics identified for Klinefelter syndrome (4)

Answer 6

• linked to poorly developed language skills and reading
  
  • Sufferers tend to be passive, shy and lack interest in sexual activity.
  • Many tend not to respond well to stressful situations
  • may often exhibit problems with ‘executive functions’, such as memory and problem solving.

Question 7

Explain turners syndrome (3)

Answer 7

• Approximately 1 in 5000 biological females have Turner’s syndrome
  
  • caused by an absence of one of the two allotted X chromosomes - this it is referred to as XO.
  • Thismeans that affected individuals have 45 chromosomes rather than the usual 46.

Question 8

What are some psychological characteristics identified for Turners syndrome (3)

Answer 8

• higher than average reading ability.
  
  • performance on spatial, visual memory
    and mathematical tasks is lower than normal.
  • As well as their immature appearance,
    people with Turner’s syndrome tend to be socially immature, have trouble relating to their peers and experience difficulty ‘fitting in’.

Question 9

What are some physical characteristics identified for turners syndrome (3)

Answer 9

• do not have a menstrual cycle (amenorrhoea),
  
  • their ovaries fail to develop and thus they are sterile.
  • do not develop breasts at puberty and instead have a broad “shield’ chest

Question 10

Explain treating kinefelter and turners syndrome (3)

Answer 10

• Testosterone: replacement therapy can help people with Klinefelter’s syndrome increase their hormone levels towards
  a normal range. This can produce bigger muscles, deepen the voice, and stimulate facial and body hair growth. Some XXY males can also benefit from fertility treatment to help them
  father children.
  
  • Growth hormone injections are beneficial for some individuals
    with Turner’s syndrome. Injections often begin in early childhood and may increase final adult height by a few inches.
  • Oestrogen replacement therapy is usually started at the time of normal puberty to start breast development. Oestrogen and progesterone are given a little later to begin a monthly menstrual period, which is necessary to keep the womb healthy.

Question 11

Evaluate how it contributes to the nature nurture debate in atypical sex chromosomes (4) (+ve)

Answer 11

• Studies of atypical sex chromosome patterns are useful as contribute to understanding of the nature-nurture debate in gender development.
  
  • comparing people who have these conditions with chromosome-typical individuals it becomes possible to see psychological and behavioural differences between the two groups
  • such as the finding that people with Turner’s syndrome tend to have higher verbal ability and tend to talk more than ‘typical’ girls
  • logically inferred that these differences have a biological basis and are a direct result of the abnormal chromosomal structure⇒ innate ‘nature’ influences have a powerful effect on psychology and behaviour.

Question 12

Evaluate environment explanation in terms of atypical sex chromsomes (2) (-ve)

Answer 12

• relationship between the chromosomal abnormalities associated with Klinefelter’s and Turner’s syndrome and the differences in behaviour seen in these individuals is not causal. It may actually be that environmental and social influences are more responsible for the behavioural differences seen in these individuals.
  
  • Eg social immaturity observed in females with Turner’s syndrome may arise from the fact that they are treated ‘immaturely’ by the people around them. Parents, teachers and others may react to the pre-pubescent appearance of people with Turner’s in a way that encourages immaturity and this may have an indirect impact upon their performance at school (hence the specific learning and developmental problems identified).
  • it is wrong to assume that observed psychological and behavioural differences are due to nature.

Question 13

Evaluate practice application in terms of atypical sex chromosomes (+ve) (3)

Answer 13

• Continued research into atypical sex chromosome patterns is likely to lead to
  earlier and more accurate diagnoses of Turner’s and Klinefelter’s syndromes
  as well as more positive outcomes in the future.
  
  • Australian study of 87 individuals with Klinefelter’s syndrome showed that those who had been identified and treated from a very young age had significant benefits compared to those who had been diagnosed in adulthood.
  • This suggests that increased awareness of these conditions may have practical application.

Question 14

Evaluate idea of typical vs atypical no terms of abnormal sex chromosomes (4) (-ve)

Answer 14

• based on the idea that there are ‘typical’ gender behaviors associated with
  males and females.
  
  • the idea that Turner’s individuals are
    socially immature is based on the
    idea that there is a typical level of
    social maturity for the vast majority
    of females.
  • idea that individuals with KS
    are shy and passive is based on the idea that shyness and passivity is not a typical behaviour
    for a male.
  • based on stereotypical assumptions of
    what constitutes ‘average’ or ‘normal’
    behaviour for males and females
    rather than fact.