1. An Introduction to GENETIC DISORDERS

2. What are genetic disorders? A genetic disorder is an abnormal condition that a person inherits through genes or chromosomes. Do you know of any genetic disorders?

3. Two types of Genetic Disorders –Gene Disorders: a genetic disorder that only affects a single gene. –Chromosome Disorders: a genetic disorder that is caused by the addition or subtraction of one or more chromosomes.

4. Cause of Genetic Disorders Genetic disorders are caused by mutations, or changes in a person’s DNA. Mutations occur when there is a change in the order of the bases in an organism’s DNA. The 3 types of mutations are: –Deletion – when a base pair is left out –Insertion – an extra base pair is added –Substitution – when an incorrect base replaces a correct base

5. Mutations Substitution –AAACACGGG –TTTGTGCCC Deletion –AAACCGGG –TTTGGCCC Insertion –AAACACCGGG –TTTGTGGCCC Original DNA Code AAACCCGGG TTTGGGCCC

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

7. Karotypes A karyotype is an organized profile of a person's chromosomes. In a karyotype, chromosomes are arranged and numbered by size, from largest to smallest. This arrangement helps scientists quickly identify chromosomal alterations that may result in a genetic disorder.

8. Making a Karyotype To make a karyotype, scientists take a picture of someone's chromosomes, cut them out and match them up using size, banding pattern and centromere position as guides. http://learn.genetics.utah.edu/content/ begin/traits/karyotype/http://learn.genetics.utah.edu/content/ begin/traits/karyotype/

9. Normal Human Karyotypes

10. Gene Disorders Cystic Fibrosis Sickle Cell Anemia Hemophilia

11. Cystic Fibrosis Cystic Fibrosis is a gene disorder. The mutation that leads to CF is on the recessive allele. People with CF must inherit 2 copies. This gene is found on Chromosome 7. Symptoms: the body produces abnormally thick mucus in the lungs and intestines, making it hard to breathe and digest food. Cystic Fibrosis

12. Sickle Cell Anemia Sickle Cell is a single gene disorder. The mutation that leads to sickle cell is on the recessive allele. People with it must inherit 2 copies. The mutation that causes sickle cell 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.

13. Sicke Cell Anemia

14. 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 scrap; or from internal bleeding due to small bumps or bruising

15. Hemophilia Hemophilia is a sex-linked gene disorder. This means the affected gene is found on the X chromosome. The mutation that leads to hemophilia is on the recessive allele. –Females must inherit 2 copies of the recessive allele to inherit hemophilia. –Males only have to inherit 1 copy of the recessive allele to inherit hemophilia because they only have 1 X chromosome. The Y chromosome does not have the hemophilia gene.

16. Normal Hemoglobin (protein) –Glutamate (amino acid) Sickle Cell Hemoglobin (protein) Valine (amino acid)

17. Chromosome Disorders Down Syndrome – 3 copies of 21 st chromosome Turner Syndrome – incomplete or missing X chromosome (girls only) Edward’s Syndrome – 3 copies of the 18th chromosome Triploidy – 3 copies of every chromosome

18. Down Syndrome Down Syndrome is a chromosome 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 a distinct physical appearance and some degree of mental retardation.

19. Smallest Girl in the world due to Primordial Dwarfism Smallest Girl in the World

20. Primordial Dwarfism Kenadie Jourdin-Bromley weighed 2 lbs., 8 ounces when she was born in February 2003. She was not expected to live more than a day, but she has survived. She continued to defy doctors expectations and at the age of 8 months, Kenadie was finally diagnosed with primordial dwarfism, a genetic condition that is believed to affect only about 100 people in the world. She stands 33 inches tall and weighs 17 pounds, roughly the size of an 18-month-old toddler. Kenadie is 7.

21. Maddox Elise and Triploidy Mrs. Hodge’s daughter Maddox Elise (Maddie) was diagnosed with Triploidy on December 31, 2008. Maddie had a total of 69 chromosomes in each cell. She had a full extra set of chromosomes.

22. Triploidy

23. Triploidy is a rare fatal genetic disorder that only happens in approximately 1% of pregnancies. Most babies diagnosed with Triploidy are not born alive. Triploidy can happen from an extra set of maternal OR paternal chromosomes.

24. Maddox Elise Hodge

25. Triploidy is RANDOM and doesn’t affect every pregnancy!