Chromosomal Disorders Nondisjunction

Down Syndrome Life Expectancy 55 yrs

Frequency of Down Average 1:700 Births 20-24 1/1400 25-29 1/1100 30-31 1/900 40 1/100 45 1/25

Edward’s Syndrome Trisomy 18 1:6,000 Births Second most common after Down Syndrome

Patau Syndrome Trisomy 13 1:12,000 Births > 80% die in first year

1:50,000

Turner Syndrome 45,X 1:2,500 Births

Klinefelter Syndrome 47, XXY tall, longer arms than legs 1:500 - 1:1000 no or low testosterone male reproductive organs under developed no sperm production develop some breast tissue

47, XYY Super Male

Triple X 47, XXX Skin folds that descend and cover the inner corners of the eyes Wide spacing between the eyes Decreased muscle tone (hypotonia) Curved fifth ("pinky") fingers Small head circumference Learning disabilities, such as delayed speech and language development, and difficulty reading Delayed motor skills, such as sitting and walking Problems processing sound Behavioral and emotional problems, including attention deficit hyperactivity disorder (ADHD), anxiety, and depression Premature ovarian failure or ovary malformations (though infertility is rare) Menstrual irregularities