Medical Genetics is a medical specialty made up of clinical geneticists who are physicians certified in multiple clinical specialties and genetic counselors who hold master’s degrees and board certification in Medical Genetics. The Department of Medical Genetics at Mayo Clinic is complemented by comprehensive on-site laboratory genetics services. The knowledge that patients gain from a visit to Mayo's Department of Medical Genetics may help them arrive at a diagnosis, plan a family, obtain better treatment for a medical condition, or improve their understanding of how a genetically based disorder affects them and their family.

The role of geneticists and genetic counselors in caring for patients is expanding, as researchers identify genes that may indicate whether patients may inherit or develop certain diseases. For instance, the Department of Medical Genetics is involved with the Mayo Clinic Cancer Center (opens in new window) to assess patient risk for developing breast, colon, and other cancers; genetic information is used to guide efforts in medical screening and preventive treatment.

Disorders addressed by clinical geneticists and genetic counselors include all age groups and types of conditions. The clinical geneticist takes on varying roles, including the diagnosis, management, treatment, and patient counseling for these conditions, which may include:

  • Rare single-gene disorders
  • Birth defects
  • Familial cancer
  • Metabolic disorders
  • Neurologic disorders
  • Multisystem disorders

What is medical genetics?

Medical Genetics is concerned with how genes and heredity affect human health. Hundreds of disorders are genetically based, for example hemophilia (a blood disorder), cystic fibrosis (a lung and digestive system disorder) and achondroplasia (a growth disorder). In virtually all cells of a person's body are 46 packages of genetic material (chromosomes). Each chromosome consists of a long chain of special chemicals called DNA (deoxyribonucleic acid). A gene is a segment of one DNA chain. Genes are linked together on this chain of DNA, and each one has a specific "address" on the chromosome. For example, the gene that controls blood type occurs in the same spot on the same chromosome in each human being.

This knowledge allows scientists to map the location of genes and identify their function. Each chromosome contains thousands of genes. In recent years, scientists have identified the genes that cause many disorders. Genetic disorders result from abnormalities -- or mutations -- in a person's DNA. These abnormalities are formed by the erroneous addition, deletion or substitution of chemicals that make up DNA. Mutations can occur spontaneously, or they can be inherited. Mutations can also be caused by the environment; for example, from exposure to chemicals or radiation.

The Department of Medical Genetics is widely recognized for its outstanding research contributions. Read more about research in the Department of Medical Genetics.

Read more about genetic testing at
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Reasons for a consultation

Although reasons for appointments may vary, in each case the patient or physician seeks more information about a medical condition that may be inherited or "genetically based." People may be referred to medical genetics by their physician, or they may visit on their own. Reasons for an appointment may include:

  • Patients with a disorder believed to be inherited
  • Couples who have a child with an inherited disorder, birth defect or mental retardation
  • Couples who desire testing or more information regarding a disorder that occurs frequently in their family or ethnic group
  • Couples who are expecting a baby and wish to learn about the health of their unborn child
  • Couples who plan on becoming parents and want to learn if a child might inherit a disorder
  • People who have multiple medical problems that may have a single genetic cause
  • Women who have had three or more miscarriages or babies who have died in infancy
  • People who have an inherited disease and are concerned how it may affect family members
  • People who may not have a disorder, but are concerned because there is a family history of the disorder
  • People who have certain types of cancer and/or whose family has a history of cancer and are concerned about their risk or that of their children

A typical visit

Patients should bring medical and test records to their consultation -- and gather as much information as possible about their family's health history. At a minimum, this should include information about close relatives, living and deceased: grandparents, parents, siblings, children and grandchildren. Also useful may be to know the health histories of aunts, uncles, cousins, nieces and nephews. In some instances, the health histories of more distant relatives are important. To ensure confidentiality, no names are entered into medical records or into any official reports. Even if a patient is adopted or knows nothing about his or her family history, a visit to Medical Genetics can be helpful to assess risk for a genetic condition.

Because certain genetically based disorders can occur more frequently in one ethnic group than another, noting the ethnic origin of each side of one’s family is worthwhile. For example, cystic fibrosis is more common in northern Europeans, and sickle cell anemia is more common in African-Americans.

Usually, patients can expect to spend about one and a half to two hours during a visit to Medical Genetics. Upon arrival, patients may first meet with a medical genealogist and/or a genetic counselor, who will collect and record any information about family medical history. Then the patient will meet with a genetic counselor, a medical geneticist, or both, depending on the reason for the visit.