1. Human Genetic Disorders

2. Genetic Disorders
A genetic disorder is an abnormal condition that a person inherits through genes or chromosomes.
Genetic disorders are caused by mutations, or changes in a person’s DNA.

3. Mutations
Mutations occur when there is a change in the order of the bases in an organism’s DNA.
Deletion: When a base pair is left out.
Insertion: an extra base pair is added.
Substitution: when an incorrect base replaces a correct base.

4. Mutations Original DNA Code Insertion Deletion Substitution
A A A C C C G G G
T T T G G G C C C
Insertion
A A A C A C C G G G
T T T G T G G C C C
Deletion
A A A C C G G G
T T T G G C C C
Substitution
A A A C A C G G G
T T T G T G C C C

5. Mutagen A mutagen is anything that can cause a mutation in DNA.
Examples of mutagens include:
Radiation
Asbestos
Chemicals in cigarette smoke
Pollution

6. Cystic Fibrosis
Cystic fibrosis is a genetic disorder which the body produces abnormally thick mucus in the lungs, making it hard to breathe.
In the intestines, the mucus makes it difficult for digestion.
The mutation that leads to cystic fibrosis is on the recessive allele.

7. Sickle Cell Disease
The mutation that causes sickle cell disease affects the production of an important protein called hemoglobin.
Hemoglobin is the protein in red blood cells that carry oxygen.
People with sickle cell disease suffer from lack of oxygen in the blood and experience pain and weakness

9. Hemophilia
Hemophilia is a genetic disorder in which a person’s blood clots very slowly or not at all.
These people do not produce one of the proteins needed for normal blood clotting and could die from a minor cut or scrape; or from internal bleeding due to small bumps or bruising.

10. Down Syndrome
Down syndrome is a genetic disorder in which a person’s cells have an extra copy of chromosome #21.
The extra chromosome is due to an error in meiosis.
People with down syndrome have distinctive physical appearance, and have some degree of mental retardation.