Medical Geneticist: Your Genetic Disease & DNA Testing Specialist

Medically Reviewed By William C. Lloyd III, MD, FACS
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What is a medical geneticist?

A medical geneticist specializes in using genetic information and DNA tests to diagnose, treat, manage or prevent inherited genetic disorders, chromosome defects, and diseases and conditions influenced by genetic factors. A medical geneticist is either a scientist or physician with expertise in understanding how genes and heredity affect health and disease.

Medical geneticists work in clinical and laboratory settings in hospitals, research institutes, government agencies, pharmaceutical companies, and other commercial companies. A medical geneticist may or may not have direct contact with patients, but works in healthcare

to reduce the risk and minimize the impact of genetic disorders and conditions on individuals, families and groups. Medical geneticists also have expertise in ethical, legal and social issues associated with genetic testing and treatments.

Depending on their education, training, and area of specialization, a medical geneticist:
  • Evaluates a patient’s health history and risk of developing genetic or gene-related disorders and conditions

  • Diagnoses genetic disorders and conditions

  • Counsels patients about genetic disorders and their risk of inheriting or passing along genetic disorders. Counseling includes providing emotional and psychological support and referrals.

  • Consults with your personal physician and other specialists about genetic test results and to develop and monitor your treatment plan

  • Treats patients who have genetic conditions (if the doctor is a licensed physician)

  • Oversees genetic laboratory procedures and operations

A medical geneticist may also conduct research, develop gene therapy protocols, and create new genetic tests. They may also teach medical genetics at the undergraduate, graduate and postgraduate level.

A medical geneticist may be known as a geneticist or laboratory geneticist. A medical geneticist may also use the name of a specific genetic specialty or subspecialty, such as clinical biochemical geneticist or clinical cytogeneticist.

When do you see a medical geneticist?

Genetic disorders and conditions are caused either by a genetic change (mutation) or chromosome defect that you inherit or that occurs during your lifetime. Your personal physician or other specialist may send you to a medical geneticist for genetic testing, or to diagnose, manage, treat and counsel you for genetic disorders or conditions.

You or your doctor may consult with a medical geneticist under the following situations:

  • You have a family history of a genetic disorder or disease such as Huntington’s disease.

  • You are concerned about health risks and other problems related to your family medical history.

  • You have symptoms of a genetic disorder or disease.

  • You have cancer including leukemia, lymphoma, or other type of cancer. Medical geneticists can look at the genetic defects in cancer cells to help design a treatment plan.

  • You are concerned about passing on a genetic disorder to your children. Medical geneticists can determine the likelihood of passing on the genetic trait to your children, as well as test embryos for certain genetic defects prior to implantation.

  • You are pregnant and would like prenatal genetic testing before your baby is born. Prenatal genetic testing can detect genetic defects and possible disorders. Genetic testing may also be helpful in cases of infertility and recurrent pregnancy loss.

If you need help understanding an inherited genetic disorder or your risk factors for developing or passing on a genetic disease, discover medical genetic specialists near you.

What does a medical geneticist diagnose or treat?

You might see a medical geneticist for the following types of conditions:

  • Chromosomal disorders including trisomy 21 (Down syndrome), trisomy 13 (Patau syndrome), and trisomy 18 (Edwards syndrome)

  • Congenital anomalies or birth defects including cleft lip and cleft palate, heart and kidney defects, spina bifida, and clubfoot

  • Inherited genetic disorders including cystic fibrosis, sickle cell anemia, hereditary hemochromatosis, hereditary hearing loss, hemophilia, Marfan syndrome, Huntington’s disease, and inborn errors of metabolism, such as phenylketonuria (PKU), fructose intolerance, and glycogen storage disorders

  • Multifactorial disorders including arthritis, diabetes, cancer, obesity, heart disease, and high blood pressure. A combination of a genetic and environmental factors cause these disorders.

What does a medical geneticist test?

Tests vary depending on the medical geneticist’s specialty but may include:

  • Cancer testing for early detection, diagnosis, and treatment of acquired or inherited cancer syndromes, as well as determine the aggressiveness of a cancer

  • Carrier testing to determine if a person carries a gene for a genetic disorder that might be passed to a child. Examples include cystic fibrosis, sickle cell anemia, and Tay-Sachs disease.

  • DNA fingerprinting for use in maternity and paternity cases and in organ transplant programs to identify potential organ donors. In DNA fingerprinting, geneticists sequence several sections of DNA from a blood or other type of sample and check for matches to the same sections from other people or samples. DNA fingerprinting is also used to identify bacteria, viruses, and other disease-causing organisms.

  • Newborn screening including screening for phenylketonuria (PKU), sickle cell disease, cystic fibrosis, and congenital hypothyroidism

  • Predictive gene testing to help identify the risk of developing a disease or the presence of disease before symptoms occur. Examples include Marfan syndrome, hemochromatosis, colorectal cancer, breast cancer, and ovarian cancer.

  • Prenatal testing to identify disorders before birth such as Down syndrome. Medical geneticists also investigate infertility and recurrent pregnancy loss.

What procedures and treatments does a medical geneticist do?

Specific procedures and treatments depend on whether the geneticist is a physician who sees patients or a scientist (PhD) who predominantly performs tests and analyzes results but does not see patients. Procedures and treatments may include:

  • Genetic consulting, which involves advising physicians and other medical specialists about the diagnosis, management and treatment of genetic disorders and conditions

  • Genetic counseling, which involves teaching patients about genetics and its role in disease; identifying medical management issues; identifying and advising patients about genetic risks; and providing appropriate referrals

  • Genetic evaluation, which involves your physical exam, your family history, and other factors and risks factors for genetic disorders and conditions

  • Gene therapy, which involves treating or preventing a disease by correcting an abnormal gene. With some exceptions, gene therapy is experimental and limited to research and clinical trials. Researchers are studying gene therapy for cancer, Alzheimer’s disease, hemophilia, Parkinson’s disease, chronic granulomatus disorder (CGD), and severe combined immune deficiency (ADA-SCID), among many others. A recent advance is a gene therapy technique for a form of pediatric leukemia.

Medical geneticist training and certification

Education, training, experience, and board certification by the American Board of Medical Genetics (ABMG) help establish a medical geneticist’s expertise. Board certification requirements vary depending on the specialty. In general, a medical geneticist has:

  • Completed four years of medical school, earning an MD or DO degree; or completed graduate school, earning a PhD in genetics, human genetics, or a related field

  • Completed a laboratory genetics postdoctoral training program in a medical genetics and genomics specialty: clinical biochemical genetics, clinical cytogenetics and genomics, clinical genetics and genomics, or clinical molecular genetics and genomics. As of July 1, 2017, clinical genetics and genomics and clinical molecular genetics and genomics have merged into one specialty: laboratory genetics and genomics.

  • Passed a certification exam that validates the doctor’s specialized knowledge and skill in a specialty of medical genetics

To maintain board certification, a geneticist must complete the ABMG’s Maintenance of Certification program every 10 years.
The specialties of medical genetics include:

  • Clinical biochemical genetics focuses on diagnosing and managing inherited metabolic disorders such as phenylketonuria.

  • Clinical cytogenetics focuses on chromosome and DNA tests to diagnose and manage chromosomal disorders and conditions including recurrent miscarriage, certain birth defects, and cancer.

  • Clinical genetics focuses on providing medical care to individuals and families who have a hereditary syndrome or are at risk of developing genetic diseases and disorders.

  • Clinical molecular genetics focuses on a broad range of molecular tests, such as DNA tests to diagnose and manage genetic disorders, infectious diseases, and cancer.

Subspecialties of medical genetics include:

  • Medical biochemical genetics focuses on the diagnosis, medical treatment, and management of people with inherited metabolic disorders such as phenylketonuria (PKU).

  • Molecular genetic pathology focuses on using genetic and molecular testing to diagnose, monitor and study genetic and gene-influenced disorders, such as cystic fibrosis and sickle cell anemia, as well as cancer and infections.

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2017 Nov 2
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
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