Atypical sex Chromosome Patterns

• Atypical sex chromosome patterns


  any sex chromosome pattern that deviates from the usual xx/xy formation
• Klinefelter's syndrome


  Affecting about 1 in 600 men, an individual's genotype has an extra X chromosome (XXY). 10% of cases are identified by prenatal diagnosis, 2/3 of people with the disorder are likely not aware of it and diagnosis often comes about accidentally via a medical examination for something unrelated.
• Physical characteristics of Klinefelter syndrome


  There may be some breast development at puberty, long limbs, underdeveloped genitals, reduced body hair and may have problems with coordination and clumsiness.
• Psychological Characteristics of Klinefelter's syndrome


  Klinefelter's syndrome is often linked to poor language development and reading ability. They tend to be passive, shy and lack interest in sex. Many tend not to respond well to stress and may show issues with 'executive functions' such as memory and problem-solving.
• Turner's Syndrome


  A chromosomal disorder which affects about 1 in 5000 women only has one X chromosome (XO) causing developmental abnormalities and infertility. They have 45 chromosomes rather than 46.
• Physical Characteristics of Turner's Syndrome

  Individuals with Turner syndrome do not have a menstrual cycle, their ovaries fail to develop and thus are sterile. They do not develop breasts and instead have a broad shield chest. It is also associated with low-set ears, a 'webbed' neck and a high waist-to-hip ratio in that the hips are not much bigger than the waist. Generally, adults with Turner syndrome are physically immature and tend to retain the appearance of prepubescent girls.
• Psychological characteristics of Turner's syndrome 


  A feature of Turner's syndrome is higher-than-average reading ability, however spatial, memory and mathematical performance in tasks is lower than normal. As well as immature appearance, they tend to be socially immature have trouble relating to peers and experience difficulty 'fitting in'.
• Contribution of sex chromosome research to nature/ nurture

  A strength of research into atypical sex chromosome conditions is its contribution to the nature-nurture debate. By comparing people who have these conditions with chromosome-typical individuals, it becomes possible to see psychological and behavioural differences between the two groups. It might be logically inferred that they have a biological basis and are a result of the abnormal chromosomal structure. Supporting the view that innate 'nature' influences have a powerful effect on psychology and behaviour.
• The issue with assuming differences are solely related to chromosomes


  Environmental and social influences may be responsible for behavioural differences. E.g. social immaturity seen in females with Turner's syndrome may arise from the fact they are treated 'immaturely' by the people around them. People may react to the prepubescent appearance in a way that encourages immature behaviour, having an indirect impact on their performance at school. This shows it could be wrong to assume psychological and behavioural differences in people with atypical sex chromosome patterns are due to nature.
• Application of research into atypical chromosomal conditions

  Continued research is likely to lead to earlier and more accurate diagnoses of the syndromes and more positive outcomes in the future. An Australian study of 87 individuals with Klinefelter's syndrome showed those who had been identified and treated from a young age experienced significant benefits in terms of managing their condition, compared to those who had been diagnosed in adulthood. This suggests that increased awareness of these conditions has useful real-world applications.
• Sampling issue with chromosomal research


  To identify characteristics a large sample is needed of people with symptoms that range in severity, however, mostly people with severe symptoms are identified and therefore the picture of typical symptoms may be distorted. Boada et al reported prospective studies (from birth) have produced a more accurate idea of characteristics, e.g. many people with Klinefelters don't have cognitive or psychological problems and are highly successful academically and socially. Suggesting typical characteristics may be over-exaggerated.
• Issue with knowledge of Klinefelter syndrome


  Many people with Klinefelter syndrome may be unaware of it, this may be good as it avoids a self-fulfilling prophecy- knowing you have the condition creates self-expectation of what your capabilities are. On the other hand, early knowledge of the condition is why they appear and act differently from children of the same age. This means that the child doesn't feel physical and behavioural issues are their fault. It also means early access to medical and psychological support available.