Atypical Chromosomes

• what is klinefelter's syndrome?

  • occurs in 1 in 600 males
  • characterised by an XXY
• what is turner's syndrome?

  • 1 in 2000 females
  • characterised by an XO chromosome pattern (where the other X chromosome is absent)
• symptoms of Klinefelter's

  Physical

  • enlarged breasts as a result of excess oestrogen
  • lack body hair

  Psychological

  • poorer verbal and reading skills
  • passive and quiet
• symptoms of turner's


  physical

  • underdeveloped ovaries leading to menstrual cycle problems
  • webbed neck and broad shoulders

  psychological

  • higher than average reading and verbal skills
  • struggle to maintain social relationships
• evaluating Klinefelter Syndrome (1)

  • criticised for ignoring individual differences. 1 in 10 people can develop ‘mosaic’ Klinefelter Syndrome which occurs when the additional X chromosome only appears in some of their cells rather than all of them, reducing the severity of their symptoms. This suggests that when diagnosing or researching Klinefelter Syndrome, researchers must consider that there are individual differences and variations of the condition, and avoid assuming that everyone will experience the same physical and psychological characteristics.
• evaluating Klinefelter Syndrome (2)

  • population validity: Klinefelter Syndrome diagnoses are easier when symptoms are severe and noticeable therefore, there is likely to be a number of people who remain unaware that they have the syndrome, with symptoms that may not be visible or problematic enough to seek medical help. This means that any research is only based on severe cases and is unrepresentative of the full spectrum of people living with the syndrome. The consequence of only studying those with severe symptoms is that we do not have insight into how milder symptoms.
• evaluating Klinefelter Syndrome (3)

  • A strength of research into Klinefelter Syndrome is that is enables early intervention. Detecting and intervening early in Klinefelter Syndrome has been shown to benefit individuals when it comes to coping and managing their symptoms. One study found that those who were diagnosed and treated early benefitted from intervention and support more than those who were not diagnosed until adulthood. This concludes that medical research is crucial in understanding the syndrome so that early detection and diagnosis can improve access to intervention for everyone.
• evaluating Klinefelter Syndrome (4)

  • One advantage of biological research into Klinefelter Syndrome is the ability to manufacture treatment. Treatments including testosterone replacement therapy (TRT) (to increase testosterone levels and improve characteristics such as increasing facial hair and reducing breast size) are available following biological investigations.
• evaluating Turner Syndrome (1)

  • One criticism of research into Turner Syndrome is the assumption that everyone develops the same associated chromosomes. Individuals with Turner Syndrome may present with a ‘mosaic’ form of the syndrome, where the X chromosome is only missing from some bodily cells rather than all of them. This would result in milder symptoms of Turner Syndrome and suggests that not all females who present with X0 chromosomes will develop in the same way. Therefore, explanations of Turner Syndrome should be on a case-by-case basis and avoid generalised assumptions and prognoses.
• evaluating Turner Syndrome (2)

  • A strength of research into Turner Syndrome is the positive implications for treatment that it has led to. Females diagnosed with Turner Syndrome can now be treated with oestrogen replacement therapy (ORT) to increase oestrogen levels that have been lowered by the absent X chromosome. This treatment will help with breast and reproductive development and may reduce the social pressures faced by girls with Turner Syndrome, increasing their confidence and making them feel more accepted.
• evaluating Turner Syndrome (3)

  • lacking population validity. As with Klinefelter Syndrome, it is likely that females who are diagnosed with Turner Syndrome have presented with severe and therefore noticeable symptoms. This means that any research into Turner Syndrome, including research into treatment effects, is based on an unrepresentative sample and does not include those who have the syndrome but experience milder symptoms.
• evaluating atypical chromosmes

  • socially sensitive: a diagnosis of a syndrome and symptoms can infer that there is something wrong with those who have them. Secondly, it is possible to diagnose these conditions prenatally by inspecting the physical features of a foetus. Although this may help with early detection, this is ethically questionable since it could lead to labelling and different treatment of the children once born, or it could lead to parents seeking termination of pregnancies.
• evaluating atypical chromosomes

  • nature and nurture: Although nature helps to explain the prenatal, physiological traits of both syndromes, nurture and experience should be considered to explain the psychological traits. For example, being treated differently by peers and adults may be the root cause. Females with Turner Syndrome are typically immature and childlike; however, this may be the result of being treated this way by adults and thus reinforcing the psychological traits. Therefore, it is hard to know which symptoms of Turner Syndrome are wholly the result of nature or not.