Atypical Sex Chromosome Patterns

Question 1

what are the two syndrome that are due to atypical sex chromosomes?

Answer 1

• Klinefelter’s syndrome
• Turner’s syndrome

Question 2

what is Klinefelter’s syndrome?

Answer 2

• presence of an extra X chromosome : XXY
• affects 1 in 600 males
• 10% of cases can be identified by prenatal diagnosis
• 2/3s of people with KF are not aware of it

Question 3

what are the physical traits of Klinefelter’s syndrome?

Answer 3

• reduced body hair
• some breast development (gynaecomastia)
• ‘softening’ or ‘rounding’ of body contours
• underdeveloped genitals
• problems with co-ordination and general clumsiness

Question 4

what are the psychological traits of Klinefelter’s syndrome?

Answer 4

• poorly developed language skills and reading ability
• passive and shy
• lack interest in sexual activity
• problems with executive functions such as memory and problem solving

Question 5

what is Turner’s syndrome?

Answer 5

• absences of an X chromosome: XO
• has 45 chromosomes rather than 46
• affects 1 in 5000 females

Question 6

what are the physical traits of Turner’s syndrome?

Answer 6

• don’t have a menstrual cycle (amenorrhoea)
• ovaries don’t develop so they are infertile
• do not develop breasts, have a broad ‘shield’ chest
• low set ears
• webbed neck
• short stature

Question 7

what are the psychological traits of Turner’s syndrome?

Answer 7

• higher than average reading ability
• spatial, visual memory and mathematical tasks are lower than average
• socially immature
• trouble relating to their peers and experience difficulty fitting in