Atypical sex chromosome patterns

• Identify the two atypical sex

  chromosome patterns.

  Klinefelter’s syndrome (XXY) and Turner’s syndrome (XO).
• Outline Klinefelter’s syndrome.

  Klinefelter’s syndrome is a chromosomal disorder that affects 1 in 1000 males.

  These males have XXY chromosomes rather than the typical XY pattern.

  This leads to physical/sex differences such as breast development, a lack of facial hair and longer limbs.

  It also leads to psychological/gender differences such as a shy and passive temperament, poorly developed language skills and more easily upset.
• Outline Turner’s syndrome.

  Turner’s syndrome is a chromosomal disorder that affects 1 in 5000 females.

  These females are missing an X chromosome (XO) rather than having the typical XX pattern.

  This leads to physical/sex differences such as reduced breast development, a webbed neck and being short in height.

  It also leads to psychological/gender differences such as impaired social skills and difficulties fitting in, higher than average language skills but poor maths skills.
• Evaluate research into atypical sex chromosomes: role of chromosomes on sex and gender.


  Research compared sex and gender characteristics between those with typical and atypical sex chromosomes.

  Males with Klinefelter’s syndrome experience breast growth and are shy and passive whereas XY males do not develop breasts and are more aggressive. Females with Turner’s syndrome have reduced breast growth and impaired social skills whereas XX females have more breast growth and better social skills. This is a strength because it shows that atypical sex chromosomes result in atypical sex and gender.
• Evaluate research into atypical sex chromosome patterns: confounding variable. 


  The shy and passive temperament seen in males with Klinefelter’s syndrome is a result of the bullying they may have experienced due to their increased breast growth. The impaired social skills and difficulties fitting in seen in females with Turner’s syndrome may be a result of bullying they may have experienced due to their webbed neck. This is a limitation because it could be argued that gender differences in people with Klinefelter’s and Turner’s syndrome may be due to environmental factors.
• Evaluate research into atypical sex chromosome patterns: small sample sizes. 


  This is because Klinefelter’s and Turner’s syndrome are rare syndromes - Klinefelter’s syndrome occurrs in only 1 in 1000 men and Turner’s syndrome occurs in only 1 in 5000 females. This is a limitation because small sample sizes limits the generalisability of conclusions when investigating the role of chromosomes on sex and gender.