1. These disorders cannot be cured but are not contagious
Genetic Disorders
May result from a change in DNA…a single base pair may be substituted, added or left out. Changes in chromosome number can also lead to genetic problems.
These disorders cannot be cured but are not contagious

2. Humans have 23 pairs of autosomal chromosomes and 2 sex chromosomes
Normal Karyotype
Humans have 23 pairs of autosomal chromosomes and 2 sex chromosomes
XX produces a female while XY produces a male... the father always determines the sex of the child since the mother can only contribute an X chromosome

3. Mutations occur all the time in every cell in the body
Mutations occur all the time in every cell in the body. Each cell, however, has the remarkable ability to recognize mistakes and fix them before it passes them along to its descendants. But a cell's DNA repair mechanisms can fail, or be overwhelmed, or become less efficient with age. Over time, mistakes can accumulate.
tericooper.net/session4/Genetic_Disorders.ppt 

4. Autosomal recessive disorders
Cystic Fibrosis and
Sickle Cell Anemia
are two examples
tericooper.net/session4/Genetic_Disorders.ppt 

5. Cystic Fibrosis - Cystic fibrosis is a chronic disease in which
Cause: deletion of only 3 bases on chromosome 7
Cystic fibrosis is a chronic disease in which
the glands produce excessively sticky mucus
that can clog the bronchial tubes in the lungs,
making it difficult to breathe.

6. Organs affected by CF...

7. For autosomal recessive disorders, both Parents
must pass on
the mutation for a
child to be affected

8. Sickle-cell anemia
Also called sickle-cell disease, is a hereditary disorder in which abnormal hemoglobin *
within the red blood cells (RBCs) causes the cells to take on abnormal sickle (crescent shapes.
This may cause inflammation, pain, tissue damage, and anemia
*decreases the ability of the hemoglobin to transport oxygen
*sickled cells tend to bunch up and clog the blood vessels, and they tend to break apart more easily than normal RBCs.
Photo by: Sebastian Kaulitz

9. Normal Red Blood Cells and Sickle Cells

10. Sickle Cell and Malaria
Malaria epidemics in regions where sickle cell anemia was common caused a
large number of deaths. However, people with sickle cell anemia or carriers
of the disease always survived malaria even if they became infected.
The malaria parasite was paralysed or destroyed by sickled erythrocyte cells.
Sickled red blood cells live for only ten to 20 days, which is much lower than the 120 day lifespan of normal, healthy red blood cells. This may affect the life cycle of the malaria parasite in the body, stopping it from replicating. As the rate at which the infection spreads in the body is drastically slowed, it may give the immune system time to attack and subdue malaria completely.
Sickle_cell_distribution.jpg
Malaria_distribution.jpg

11. Change in chromosome number
Down’s Syndrome
Caused by non-disjunction of the 21st chromosome. Where meiosis does not occur correctly to separate the chromosomes.
This means that the individual has a trisomy (3 – 2lst chromosomes).
tericooper.net/session4/Genetic_Disorders.ppt 

12. Down’s Syndrome or Trisomy 21

13. Symptoms of Down Syndrome
Upward slant to eyes.
Small ears that fold over at the top.
Small, flattened nose.
Small mouth, making tongue appear large.
Short neck.
Small hands with short fingers.
Low muscle tone.
Single deep crease across center of palm.
Looseness of joints.
Small skin folds at the inner corners of the eyes.
Excessive space between first and second toe.
In addition, down syndrome always involves some degree of mental retardation, from mild to severe. In most cases, the mental retardation is mild to moderate.
tericooper.net/session4/Genetic_Disorders.ppt 

14. Sex linked disorders *are carried on the X or Y chromosomes
*most often passed from mothers to sons on an affected X chromosome
Hemophilia is the oldest known hereditary bleeding disorder.
Caused by a recessive gene on the X chromosome.
A son who inherits a defective X chromosome from his mother does not have a
healthy X chromosome to rely on the way daughters (XX) do.
tericooper.net/session4/Genetic_Disorders.ppt 

15. European Royalty and Hemophilia
History's most famous carrier of the gene for hemophilia was Victoria ( ), Queen of England and grandmother to most of the royalty in Europe. In 1853, Queen Victoria gave birth to her eighth child, Leopold, Duke of Albany, who had hemophilia and died at the age of 31 from internal bleeding after a fall.
Two of Queen Victoria's four daughters, Alice (b. 1843) and Beatrice (b. 1857), also carried the gene for hemophilia and subsequently transmitted the disease to three of Victoria's grandsons and to six of her great-grandsons.
Alice's daughter Alexandra also was a carrier of hemophilia, and she transmitted the disease to her son Alexis (b. 1904), whose father was Czar Nicholas 11 (1868—1918) of Russia. Alexis is perhaps the most famous of the European royals with hemophilia. Alexis was the heir to his father's throne and his medical condition caused much anxiety in the royal household. Historians are still discussing the role Alexis's condition played in the Russian revolution of 1918.tericooper.net/session4/Genetic_Disorders.ppt 

16. Czar Nicholas II of Russia and his family, photographed c
Czar Nicholas II of Russia and his family, photographed c. 1916, showing his wife Alexandra(who was a carrier of hemophilia), his four daughters, and (in the foreground) his son Alexis, perhaps the most famous European royal with hemophilia.

17. The very tragic disease… hairy ears
Y-linked trait, which are rare
Only 1 cure known….
The very tragic disease… hairy ears
tericooper.net/session4/Genetic_Disorders.ppt 

18. tericooper.net/session4/Genetic_Disorders.ppt