Background Information 3. Current Oversight 4. Task Force Report 5. Issues to be Addressed 6.
Different alleles produce variations in inherited characteristics, such as eye color or blood type.
Not all cases are hereditary, but four genes have been identified for familial forms of Alzheimer's disease. The risk of developing the disease if both parents carry the gene is one in four for each pregnancy. Two strands of DNA are held together in the shape of a double helix by the bonds between their base pairs. Carriers do not usually develop clinical symptoms because they have one normal copy, but they do have a 50 percent chance of passing the mutated allele to their children. Carrier testing is usually intended to help healthy people make reproductive decisions and is recommended for individuals with a family history of a recessive disease.