1. Human Genetic Disorders, Part 2
Biology Chapter 11 Section 1B
Demonstrate how modern knowledge has led to understanding the causes of certain genetic disorders

2. Objective
Demonstrate how modern knowledge has led to understanding the causes of certain genetic disorders

3. Sickle Cell Disease Also called Sickle Cell Anemia
Common in tropical regions where malaria prevalent
Not enough red blood cells to carry oxygen through the body
Sickling cells become rigid and crescent shaped
Sickling cells die prematurely
Sickling cells can slow or block blood flow
Demonstrate how modern knowledge has led to understanding the causes of certain genetic disorders

4. Demonstrate how modern knowledge has led to understanding the causes of certain genetic disorders

5. Sickle Cell Disease Sickle Cell Trait: One copy of the gene
No noticable symptoms
Sickle Cell Disease: Two copies of the gene
Anemia
Pain
Jaundice
Infection (damaged spleen)‏
Stunted growth
Demonstrate how modern knowledge has led to understanding the causes of certain genetic disorders

6. Sickle Cell Disease
Caused by point mutation in polypeptide responsible for hemoglobin
About people in US affected (mainly African American)‏
Defective gene creates protein that causes hemoglobin to fold on itself when low oxygen concentration
Demonstrate how modern knowledge has led to understanding the causes of certain genetic disorders

7. Sickle Cell Disease
Autosomal recessive gene located on short arm of chromosome 11
Gene is incompletely recessive
Point mutation is substitution of T for A (GAG turns into GTG) in sixth amino acid codon
Demonstrate how modern knowledge has led to understanding the causes of certain genetic disorders

8. Sickle Cell Disease Blood test can detect abnormal hemoglobin
Many states require test as part of newborn screening
Treatment:
Antibiotics
Pain relief
Blood transfusion
Bone marrow transplant may cure
Demonstrate how modern knowledge has led to understanding the causes of certain genetic disorders

9. Sickle Cell Disease Why does the gene remain in the population?
Heterozygote superiority with respect to malaria
Demonstrate how modern knowledge has led to understanding the causes of certain genetic disorders

10. Marfan Syndrome Occurs in one person per 5000
6000 to Americans
People unusually tall, with long fingers, legs, arms
With treatment, life expectancy can be similar to that of normal person
Demonstrate how modern knowledge has led to understanding the causes of certain genetic disorders

11. Marfan Syndrome Symptoms Tall, slender, long arms and legs
Breastbone that curves out or dips in
High arched palate and crowded teeth
Heart murmur
Extreme nearsightedness
Curved spine
Flat feet
Demonstrate how modern knowledge has led to understanding the causes of certain genetic disorders

12. Marfan Syndrome Mutations of FBN1 gene on chromosome 15
Dominant autosomal gene
Produces Fibrillin 1
Critical for connective tissue
Used in growth factors
Elastin fibers common in aorta, ligaments and eye
Demonstrate how modern knowledge has led to understanding the causes of certain genetic disorders

13. Marfan Syndrome Test: No specific test, usually symptoms observed
Treatment:
Depends on body systems affected
Cure:
None
VIDEO
Demonstrate how modern knowledge has led to understanding the causes of certain genetic disorders