1. Genetic Disorders

2. Tay Sachs Disease of the nervous system Life expectancy: <5 years
Autosomal recessive
Gene on chromosome 15

3. Autosomal Chromosomes
SEX

4. Tay Sachs
NN = Normal
Nn = Carrier
nn = affected

5. Tay Sachs
How can this disease continue to exist if all victims die before reproducing?

6. Tay Sachs N n N NN Nn n Nn nn

7. 3 chromosomes of the 21st pair.
Down Syndrome
3 chromosomes of the 21st pair.
aka: Trisomy 21

9. Mom’s chromosomes
Dad’s chromosomes
Non-disjunction
Proper Segregation

10. Down Syndrome Extra 21st chromosome Non-disjunction
1 in 700 live births

11. Cystic Fibrosis Thick mucous-clogged lungs Constant coughing
Autosomal recessive
(Not carried X or Y)

12. How many chromosomes are autosomal?44

13. Cystic Fibrosis
NN = Normal
Nn = Carrier
nn = affected

14. Huntington's Nerves/muscles break down
Brain function/psychiatric problems
Autosomal Dominant
(not on X or Y)

15. Huntington's
HH = Affected
Hh = Affected
hh = Normal

16. Sickle-Cell
Autosomal Recessive
Life expectancy: ~ 50 years

17. Sickle-Cell Sickle-Celled blood cells are resistant to malaria
Malaria: a mosquito-bourne disease Sickle-Cell has been naturally selected for its resistance to malaria, therefore more common in tropic areas.

18. Kleinfelter’s XXY
Nondisjucntion
Normal

19. Kleinfelter’s XXY 47 XXY – 1 in 500 births
48 XXYY – 1 in 18k to 50k births
49 XXXXY – 1 in 100k births
Just as healthy as normal children, but infertile

20. Kleinfelter’s XXY

21. Turner’s Syndrome (45X) Missing an X chromosome 1 in 5000 live births
98% die before birth
Short stature
Swelling of the hands and feet
Low hairline
Low-set ears
Reproductive sterility
Increased weight, obesity
Shortened metacarpal IV, small fingernails
Webbed neck
Visual impairments, ear infections and hearing loss

22. Common Genetic Disorders
Tay Sachs (autosomal recessive)
Down Syndrome (21st pair)
Cystic Fibrosis (autosomal recessive)
Huntington’s (autosomal dominant)
Sickle-Cell (autosomal recessive)
Kleinfelter’s (23rd pair)
Turner’s Syndrome (23rd pair)