Human Genetic Disorders

What are Genetic Disorders? Genetic disorder- an abnormal condition that a person inherits through genes or chromosomes Genetic disorders are caused by mutations The mutation may occur when sex cells form or may be passed down from parent to offspring

Cystic Fibrosis Body produces abnormally thick mucus in the lungs and digestive system Symptoms: Difficulty breathing Bacteria in lungs can cause infections Digestive problems Mutation is caused by a recessive allele Most common in people of northern European descent Currently no cure Treatment: drugs to prevent infection physical therapy

Sickle-Cell Disease Red blood cells are sickle shaped, resulting from abnormal production of the protein hemoglobin Hemoglobin is responsible for carrying oxygen in the blood Symptoms: Lack of oxygen in the blood Pain and weakness Most common in people of African descent Currently no cure Treatment: Drugs to relieve symptoms and to prevent blockages in veins

Hemophilia A genetic disorder in which a person’s blood clots very slowly or not at all due to a missing protein Potential to bleed to death from small cuts or minor bumps and bruises Caused by a recessive allele on the X chromosome Occurs more frequently in males Treatment: Regular doses of missing protein Avoid contact sports

Huntington’s Disease A genetic disease that causes the gradual breakdown of cells in the brain Caused by a dominant allele Is a fatal disease with no cure Symptoms appear around age 30

Down Syndrome A genetic disorder caused by an extra chromosome 21 The extra chromosome is a result of an error during meiosis Symptoms: Distinctive physical appearance Some degree of mental retardation Heart defects

Diagnosing Genetic Disorders Scientists use tools such as Amniocentesis Doctor uses a long needle to remove fluid surrounding the baby Fluid contains cells that are analyzed in a karyotype Karyotypes A picture of all the chromosomes in a cell Doctors arrange chromosomes in pairs Look for correct number and shape of chromosomes Can be used to determine sex of baby

Genetic Counseling People may have genetic counseling if they have a history of genetic disorders in their families Genetic counselors use karyotypes, pedigree charts, and Punnett squares to determine a couple’s chances of having a child with certain genetic disorders