The following are some of the more than 900 genetic tests currently available. Most tests are for rare hereditary diseases. Some of these tests show whether or not a disease is present, but others (those marked with an asterisk) indicate only whether a person is at higher risk than normal for a given disease.

Alzheimer’s disease*
Amyotrophic lateral sclerosis (Lou Gehrig’s disease)
Breast or ovarian cancer*
Colon cancer*
Cystic fibrosis
Hemochromatosis
Hemophilia
Huntington’s disease
Muscular dystrophy
Phenylketonuria
Sickle-cell anemia