Atypical chromosome patterns

Atypical sex chromosome patterns

Klinefelter's syndrome

• Affects between 1/500 and 1/1000
• People who have this condition are biological males but have an extra X chromosome
• XXY
• Physical characteristics:
  • Reduced body hair
  • Some breast development at puberty
  • Long, gangly limbs 
  • Underdeveloped genitals
  • Problems with co-ordination
• Psychological characteristics
  • Poorly developed language skills
  • Passive, shy, lack libido
  • Exhibit problems with 'executive functions', memory and problem solving

Turner's syndrome

• 1/5000 biological females 
• Caused by an absence of one of two allotted X chromosomes
• XO
• Have 45 chromosomes, not 46
• Physical charcteristics:
  • Do not have a menstrual cycle
  • Ovaries fail to develop, sterile
  • Do not develop breasts, broad chest
  • Low set ears and webbed neck
  • Physically immature and retain appearance of a pre-pubescent girl
• Psychological characteristics
  • Higher than average reading ability
  • Performance on spatial, visual memory and maths tasks is lower than normal
  • Socially immature, have trouble…