1. Genetic Disorders

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

3. Types of Disorders Single Gene Disorders Chromosomal Abnormalities
A mutations causes the protein product to be altered or missing
Chromosomal Abnormalities
Entire chromosomes, or large segments of them are missing, duplicated, or altered.
Multi-factorial Disorders
Result from mutations in multiple genes coupled with environmental causes

4. Single Gene Disorders Cystic Fibrosis
Recessive disorder
Usually helps move salt into & out of the cell
When defective it causes a thick, sticky mucous to be made
Causes issues with digestive system & lungs

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

6. Single Gene Disorder Huntington’s Disease
Dominant disease
Causes brain cells to be destroyed that deal with movement, emotion, & thinking

7. Single Gene Disorder 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)
Can’t eat protein!

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
Causes too much protein to be made, which causes problems

12. Sex-linked or X-linked Traits
More genes can be carried on the X chromosome than 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