Cells & Heredity

Human Genetic Disorders

Chapter 4

Section 2

Genetic Disorder

• Genetic Disorders are caused by mutations– Changes in an organism’s DNA

Cystic Fibrosis

• Thick mucus builds up in the lungs and intestines– Hard to breath– Difficulties digesting

• Northern European Ancestry– On Average, 4 babies

per day born in U.S. with CF

Sickle-Cell Disease

• Abnormal hemoglobin formed in red blood cells– Can not carry much O2

from the lungs to the body

• African Ancestry– 9% of African Americans

Hemophilia

• Blood does not clot correctly– Can easily bleed to

death

• “Royal Disease”– Queen Victoria of England

in 1800’s• Passed it onto her son and

several of her daughters were carriers

• Her granddaughter married the Russian Czar Nicholas II

– Passed the gene to their children

Down Syndrome

• Trisomy of the 21st Chromosomal pair

• Mental Retardation– Can be mild/severe

• Heart Defects– Usually treatable

Diagnosing Genetic Disorders

• Amniocentesis– Doctor uses long needle to remove amniotic

fluid• Contains baby’s cells

Karyotype

• A picture of baby’s chromosomes– Used to detect genetic abnormalities

Genetic Counseling

• Helps couples to determine their chances of having a child with particular genetic disorders