Genetic Diseases PDF

## Genetic Disease **Genetic disease** - disease caused by defective genes that results in the loss of activity of some enzyme. ### Common Genetic Diseases 1. **Wilson's disease** - disease caused by the body's failure to eliminate copper ions (Cu²) because of lack of enzyme ceruloplasmin. 2. **Al...

## Genetic Disease **Genetic disease** - disease caused by defective genes that results in the loss of activity of some enzyme. ### Common Genetic Diseases 1. **Wilson's disease** - disease caused by the body's failure to eliminate copper ions (Cu²) because of lack of enzyme ceruloplasmin. 2. **Albinism** - caused by lack of enzyme tyrosinase, which is necessary for the formation of melanin, the pigment of the hair, skin, and eyes. 3. **Hemophilia** - caused by missing protein, an antihemphilic, globulin, which is important in the normal clotting of the blood. 4. **Muscular dystrophy** - disease caused by lack of protein dystrophin. This disease primarily affects boys and causes progressive weakness and wasting of muscles. 5. **Niemann-Pick Disease** - caused by lack of enzyme sphingomyelinase, which causes accumulation of sphingomyelin, in the liver spleen, kidney, bone marrow and lymph nodes. This affect the brain and cause mental retardation and early death. 6. **Gaucher's disease** - caused by lack of enytme glucocerebrosidase, which is necessary for the cleavage of glucocecerebrosidase into glucose and ceramide. This disease is characterized by the accumulation of glycolipid in the spleen and liver. 7. **Tay Sach's disease** - due to lack of enzyme hexosaminidase A leading to the accumulation of glycolipid in the brain and the eyes. Red spot show up in the retina, and there is also muscular weakness. 8. **Lou Gehrig's Disease** - Amylotrophic Lateral Disese ALS also known as Lou Gehrig's disease, is characterized by the degeneration of the nerve that control motor activity in thebrain and spinal cord. 9. **Sickle cell anemia** - An inherited blood disorder where red blood cells (RBCs) become sickled/crescent shape. It causes frequent infections, swelling in the hands and legs, severe tiredness and delayed growth. 10. **Phenylketunoria** - results when the enzyme phenyalalnine is absent. A person with PKU cannot convert phenylalanine to tyrosine and so the phenylalanine accumulates in the body resulting in injury to the nervous system. 11. **Galactosemia** - results from lack of enzyme uridyl transferase. Which catalyzes the formation of glucose from galactose. This disease may result in an increase in the concentration of galactose in the blood. 12. **Farber's disease** - due to lack of enzyme ceramidase is characterized by horseness, dermatitis, skeletal degenaration and mental retardation. 13. **Krabbe's disease** - due to lack of enzyme Beta-galactosidase is characterized by mental retardation and the absence of myelin. ## Classification of Genetic Diseases 1. **Chromosomal disorder** - in which there is an excee or loss of chromosomes, deletion of part of a Chromosomes, or translocation of a chromosomes. Examples include Down's syndrome, and chronic myelogenous leukemia - **Monogenic disorders** - which involve one mutant gene. This category maybe further subdivided into: - **Autosomal dominant**. Example; Huntington's disease - **Autosomal recessive**. Example; Cystic fibrosis - **X-linked**. Example; Hemophilia - **Multifunctional disorders** - involve the action of a number of genes. One example is essential hypertension. ## Treatment of Genetic Diseases 1. **Correct the metabolic consequences of the disease by supplying the missing product.** For example, a patient with familial goiter can be treated with the missing hormone L-thyroxine. 2. **Replace the missing enzymes or hormone.** Examples, injection of Beta-glucosidase in the treatment of Gaucher's disease and injection of factor VIII in the treatment of himophilia. 3. **Remove excess stored substance.** Example, adminstration of vitamin B12 in the treatment of methylmelanic aciduria. 4. **Correct the major genetic abnormality.** Example is the use of liver transplantin a patient with galactosemia (primarily used in patients with advanced cases of this disease). ## Genetic markers - Defects in one part of the chromosomes that is believed can cause certain disease. Example; A genetic marker for Alzheimer's disease have been found on chromosome 21. ## Oncogenes - Are genes that appear to trigger uncontrolled or cancerous growth. ### Cancerous cells exhibit three general characteristics 1. Uncontrolled growth 2. Invasion of body tissues 3. Spread to other body parts.