1. When Something Goes Wrong…
A Look at Genetic Disorders

2. Principles of Inheritance
Pedigree chart (P. 206)
-Used to show patterns of trait transmission in a family.
HCM - hypertrophic cardiomyopathy

3. Types of Inheritance
A Human chromosome set can be broken into two groups:
1. Sex chromosomes
X & Y
2. Autosomes
The other 22 pairs!
All 46 can be analyzed using a Karotype

4. Types of Inheritance Autosomal Recessive Inheritance
Both parents heterozygous
Trait may skip a generation
Males and females affected equally
Eg. Light eye colour & Albinism

5. Types of Inheritance 2. Autosomal Dominant Inheritance
½ of children of affected parent are expected to be affected.
Trait does not skip generations.
Males and Females affected equally.
Eg. Huntington’s Disease.

6. Types of Inheritance 3. X-Linked Recessive Inheritance
Recall (from earlier)…
Mostly males!
Trait skips generations
Eg. Colour blindness, Hemophilia
TRY THIS!
“Tracking the Hemophilia Gene” worksheet

7. Genetic Disorders Are the result of Mutations…
A change in the genetic code.
Most are recessive alleles - harmful
effects are masked by dominant gene.
Visible health problems at birth - called “congenital defects”.
Defects can be a result of genetic and environmental factors.

8. Genetic Diseases – P. 205 Two Types: Single Gene defect
-Sickle Cell anemia
-Cystic Fibrosis
-Huntington’s Disease
-Muscular Dystrophy
-Hemophilia
-Colour blindness
Chromosomal defect
-Cri-du-chat syndrome
-Fragile X
-Down Syndrome
-Klinefelter & Turner Syndromes

9. Single Gene Defects

10. Chromosomal Defects