atypical sex chromosome patterns

• Atypical sex chromosome patterns - 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.
• Two examples of atypical sex chromosome patterns are Klinefelter’s and Turner’s syndrome.
• Klinefelter’s syndrome - a syndrome affecting males in which an individual’s genotype has an extra X chromosome (in addition to the normal XY)
• Physical characteristics of Klinefelter's syndrome:

  • reduced body hair
  • tall, thin physique
  • small, infertile testes and enlarged breasts
  • susceptibility to breast cancer
• psychological characteristics of Klinefelter's syndrome:

  • linked to poorly developed language skills and reading ability
  • passive, shy and lack of interest in sexual activity
  • many tend not to respond well to stressful situations
  • exhibit problems within executive functions, such as memory or problem solving
• Klinefelter's syndrome affects between 1 in 500 and 1 in 1000 people
• Turner’s syndrome - a chromosomal disorder in which affected women have only one X chromosome
• Turner's syndrome affects 1 in 5000 biological females
• physical characteristics of Turner's syndrome:

  • do not have a menstrual cycle
  • ovaries fail to develop so they are infertile
  • breasts do not develop so they have a 'broad chest'
  • low set ears and webbed neck
  • Generally adults with Turner’s syndrome are physically immature as they retain the appearance of prepubescent girls
• Psychological Characteristics of Turner's syndrome:

  • Higher than average reading ability
  • Performance on spatial, visual memory and mathematical tasks is lower than normal
  • People tend to be socially immature, have trouble reading their peers and experience difficulty ‘fitting in’.
• Studies into people with atypical sex chromosome patterns are useful as they contribute to our understanding of the nature-nurture debate in gender development.
• 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 prepubescent appearance in a way that encourages immaturity and this may have an indirect impact upon their performance at school (hence the learning and developmental problems identified).
• Herlihy et al (2011)  conducted a study in Australia involving 87 individuals with Klinefelter’s syndrome, which 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
• 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 in practical application.