1. Most mammals have one pair of sex chromosomes Males Females

2. Sex chromosomes Females have two X chromosomes.
Males have an X & Y chromosome.

3. Meiosis
During meiosis a female can only produce an egg with an X or an X chromosome.
During meiosis a male can produce a sperm with an X or a Y chromosome.

4. Meiosis & Punnett Square

5. Normal Karyotype

6. How nondisjunction can result in abnormalities in the number of sex chromosomes . . .XX
Female
Nondisjunction XX
Eggs
XXX X
XXY Y
Female
(triple X)
(Turner’s Syndrome)
Male
(Klinefelter’s
Syndrome)
Nonviable X Y XY
Sperm
Male

7. Turner’s syndrome -XO
most common sex-chromosome abnormality in females
1 out of every 2500 female births
60,000 females in the U. S.
first described in 1938

8. Turner’s syndrome symptoms
Young infants & childhood:
swollen hands and feet
wide and webbed neck
drooping eyelids
dry eyes

9. Turner’s syndrome symptoms
Older females:
short height
infertility - absence of a menstrual period
incomplete development at puberty
sparse pubic hair and small breasts
broad, flat chest shaped like a shield

10. Possible Complications
Arthritis
Cataracts
Diabetes
Thyroiditis
Heart defects
High blood pressure
Kidney problems
Middle ear infections
Obesity
Scoliosis
Alien Autopsy & Turner’s syndrome

11. Klinefelter's syndrome - XXY 1 in 850 newborn males normal physical appearance until puberty first described by Harry F. Klinefelter in 1942

12. Klinefelter's syndrome symptoms
tall height
abnormal body proportions
(long legs, short trunk)
sexual problems･enlarged breasts
little pubic, armpit, and facial hair
Infertility - underdeveloped gonads

13. Trisomy X - XXX one in every 1,000 newborn girls girls are born in the U. S. each day Dr. Patricia Jacobs identified the extra X in Trisomy

14. Trisomy X symptoms appearance similar to Klinefelter’s but female
tall stature - low weight
varying degrees of androgyny
learning disability
delayed speech & language skills
developmental delays
normal sexual development

15. XYY syndrome (supermale)

16. XYY syndrome (supermale)
1 in 1,000 males
first published by Avery A. Sandberg in Buffalo, New York
increase risk of learning disabilities
tall with severe acne
aggressive behavior
some studies show a higher % of supermales are in prisons
normal sexual development and are fertile
some medical geneticists question whether the term "syndrome" is appropriate for this condition because its phenotype is normal

17. Cat cry syndrome deletion of chromosome 5
1 in 20,000 to 50,000 live births
all ethnic backgrounds
slightly more common in females
first described by Jerome Lejeune in 1963

18. Cat cry syndrome symptoms
problems with the larynx and nervous system
infant sounds just like a meowing kitten
feeding problems because of difficulty swallowing
low birth weight and hypotonia(low muscle tone)
severe cognitive, speech, and motor delays
hyperactivity, aggression, tantrums, and repetitive movements
unusual facial features which may change over time

19. Translocation Philadelphia Chromosome (can lead to leukemia)

20. Down Syndrome Extra chromosome 21

21. Down Syndrome In the US, 1 baby in 800 is born with Down syndrome
produces mild to severe mental retardation
characterized by an increased susceptibility to many diseases

22. Klinefelter’s Syndrome
What is the disorder???
Klinefelter’s Syndrome
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23. What is the disorder???
Down’s Syndrome
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24. What is the disorder???
Turner’s Syndrome