What is Medical Genetics?
Medical Genetics is the field of medicine involved in diagnosis, management and counseling for hereditary disorders. A Medical Geneticist is an MD who has completed residency training in one of a variety of fields such as Pediatrics, Internal Medicine or Obstetrics and Gynecology followed by a 2-year Medical Genetics residency program. Most Medical Geneticists are board certified in 2-3 specialties.
Reasons a person may seek an evaluation with a Medical Geneticist may include a personal or family history of a genetic disorder a history of multiple miscarriages or fetal or neonatal loss, a desire for preconception genetic screening, abnormal results on prenatal genetic screening, a personal or family history of cancer, a family history of early or sudden death or personal or family history of early onset cardiovascular disease or dementia.
A typical visit will include a detailed medical history and a detailed, 3- generation family history. Based on history and concerns, genetic screening tests or diagnostic testing may be offered. Genetic tests often take 4-8 weeks for results depending upon the complexity of the testing.
Cancer Genetics
While 90% of cancers are sporadic and not inherited, approximately 10% are due to inherited family cancer syndromes. Clues to an inherited cancer syndrome include young age at diagnosis, rare cancers (including ovarian cancer, adrenal cancer and sarcomas), multiple types of cancer in an individual, and multiple relatives with the same cancer. The optimal way to evaluate for a family cancer syndrome is to test a person affected with cancer. If a mutation is found in a family cancer gene, at-risk relatives may be tested for that specific mutation (which is generally less costly and time-consuming than initial testing). However, testing an affected relative is not always feasible. During a cancer genetics consultation, a thorough medical and family history will be taken, and the pros and cons of genetic testing are discussed. If testing is done, results are reviewed at a follow-up visit and appropriate referrals are made.
Age & Weight Management
Weight loss may be more complicated than “calories in, calories out”. Insulin, a hormone secreted after eating leads to storage of nutrients as glucose stores in the liver and muscles (glycogen) as well as storage of fat. Normally, insulin levels rise after eating and fall to baseline levels when nutrients are stored. In some individuals however, insulin does not return to the baseline and instead remains elevated. This may be due to frequent feeding or due to excess release of insulin in an individual who is insulin resistant. Either way, chronically elevated levels of insulin impede weight loss efforts by stimulating cellular pathways for fat and sugar storage (anabolism) and inhibiting pathways for burning of fat and sugar (catabolism).
A typical blood test most physicians would order to evaluate for “pre-diabetes” or insulin resistance is a fasting blood glucose. However, fasting insulin levels rise prior to blood sugars becoming elevated, therefore this may be a better indicator of insulin sensitivity. A fasting insulin level < 7-12 is likely optimal, however many laboratory reference ranges use levels as high as 25 as normal.
Insulin may be reduced by avoiding snacking or grazing and periodic fasting. Longer periods of fasting (over 32 hours) lead to autophagy (literally “self-digestion”) which has benefits of breaking down old proteins and cellular components and burning fat followed by regeneration of new proteins and stem cells with re-feeding. In randomized controlled trials, the evidence based Fasting Mimicking Diet (FMD) called Prolon has been shown to decrease adipose (fat) tissue, reduce inflammatory blood markers including fasting insulin, reduce blood pressures, and reduce serum lipids. Six months after 3 monthly cycles of this program, subjects were found to retain approximately half of their weight loss and most of their improvements in inflammatory markers after returning to their typical diet. This program which was developed at the University of Southern California Longevity Institute has benefits similar to water only fasting, but is much more tolerable at 800-1,000 calories per day for 5 days. Prolon may be purchased at the Nashville Medical Genetics online store.