1. Genetic Disorders

2. What are they?
A disease that is caused by a recessive allele in a person’s DNA

3. Types of Disorders Single Gene Disorders Chromosomal Abnormalities
A mutation causes the protein product to be altered or missing
Chromosomal Abnormalities
Entire chromosomes, or large segments of them are missing, duplicated, or altered.

4. Cystic Fibrosis Recessive disorder
Causes a thick, sticky mucous to be made
Causes issues with digestive system & lungs

5. Sickle Cell Anemia Recessive
Causes red blood cells to be rigid & concave
They are not able to transport oxygen very well (hemoglobin)
Resistant to malaria

6. PKU (Phenylketonuria)
Recessive
Codes for an enzyme in the liver that breaks down the amino acid phenylalanine
Causes phenylalanine to build up in the blood which poisons brain cells (neurons)

7. Huntington’s Disease Dominant
Causes brain cells to be destroyed that deal with movement, emotion, & thinking

8. Chromosome Abnormalities Non-Disjunction Disorders
When homologous chromosomes or chromatids do not separate during meiosis
Results in
Monosomy – only one copy of a chromosome
Trisomy – having 3 copies of a chromosome

9. Turner’s Syndrome Only affect females X (missing X) Female appearance
Infertile
Don’t mature

10. Klinefelter’s Syndrome
Only affects males XXY (extra X)
Some female characteristics
Very little facial hair
Infertile (don’t produce sperm)

11. Down Syndrome
Trisomy of chromosome 21

12. Sex-linked or X-linked Traits
More genes are carried on the X chromosome than on the Y
Genes ONLY on X chromosomes are called “X-linked”
Since there is only one allele, the phenotype of that allele is expressed in males

13. Examples