Merck Manuals (within the United States and Canada) and MSD Manuals (outside the United States and Canada), are one of the world’s most widely used medical information resources. 

Direct-to-Consumer (DTC) genetic testing refers to tests directly requested from a laboratory by a consumer without requiring a referral from a treating practitioner. The consumer deals directly with the laboratory including collecting the sample and sending it to the laboratory, receiving the results and paying for the test. DTC genetic tests are usually marketed directly to consumers through public media such as the Internet and magazines.

Some types of cancer run in certain families, but most cancers are not clearly linked to the genes we inherit from our parents. Gene changes that start in a single cell over the course of a person's life cause most cancers. In this section you can learn more about the complex links between genes and cancer.

Advances in science have improved our knowledge of the inner workings of cells, the basic building blocks of the body. All living things are made of cells. Complex animals such as humans have trillions of cells. Cells work together to form organs, such as the heart, liver, and skin. Human bodies have several organ systems.

Cancer is a common disease, so it’s no surprise that many families have at least a few members who have had cancer.

Links to reliable genetics resources on the web.

What are the different ways in which a genetic condition can be inherited?

Some genetic conditions are caused by mutations in a single gene. These conditions are usually inherited in one of several patterns, depending on the gene involved:

An introduction to fundamental topics related to human genetics, including illustrations and basic explanations of genetics concepts.

An introduction to fundamental topics related to human genetics, including illustrations and basic explanations of genetics concepts.

Genetics Home Reference provides consumer-friendly information about the effects of genetic variation on human health.