1. Human Genetic Disorders 7 th Grade Science Mr. Bombick

2. Major Categories of Genetic Disorders Point Mutations Gene(s) Deletion(s) Chromosomal Aberrations Polygenic

3. Point Mutations Point mutations are changes within a particular gene Point mutations can be the incorrect insertion or deletion of single nucleotides A point mutation can result in an altered gene product (protein) or no gene product (protein) being made A point mutation may result in no abnormality, a lethal situation, or a genetic disease

4. Examples of Genetic Disease Resulting from Point Mutations Cystic Fibrosis Huntington’s Disease Color Blindness (sex-linked) Hemophelia (sex-linked) Sickle-Cell Disease (incomplete dominance) Phenylketonuria (PKU) Tay-Sachs Disease Crohn’s Disease

5. Examples of Genetic Disease Resulting from Gene(s) Deletion(s) Duchenne Muscular Dystrophy (sex- linked) Cri du chat Cystic Fibrosis DiGeorge Syndrome

6. Types of Chromosomal Aberrations Chromosomal rearrangement Extra chromosomes Chromosomal deletions

7. Examples of Genetic Disease Resulting from Chromosomal Aberrations Down syndrome (Trisomy of 21) Kleinfelter’s syndrome (XXY) Turner syndrome (single X) Triple XXX syndrome Philadelphia chromosome translocation- chronic myelogenous leukemia (CML)

8. Examples of Genetic Disease from Complex and polygenic Factors Genetic disorders may be complex and polygenic meaning that they are likely associated with the effects of multiple genes in combination with lifestyle and environmental factors. Although complex disorders often cluster in families, they do not have a clear-cut pattern of inheritance. This makes it difficult to determine a person’s risk of inheriting or passing on these disorders. Complex disorders are also difficult to study and treat because the specific factors that cause most of these disorders have not yet been identified.

9. Examples of Polygenic Genetic Disorders Asthma Auto-immune diseases (e.g., MS) Cancers Cleft palate Diabetes Heart disease Hypertension Inflammatory bowel disease Mental retardation Mood disorders Obesity Infertility

10. The End