Many women's health, gynecology and fertility specialists have experienced an increased demand from patients over the past several years for genetic testing. Many patients are aware of the dramatic increase in scientific knowledge and study of human genetics, and some are seeking more options. Knowing whether certain conditions are genetic can guide preventive treatment, fertility planning and even lifestyle choices.
How Women's Health, Gynecology and Genetics are Connected
In a 2018 technology assessment, the American College of Obstetricians and Gynecologists (ACOG) examined how genetics' accounting for variation in hereditary characteristics, including gene expression, pertains to everyday health.
Epigenetics is a key area for patients to understand. This field describes the changes to individual genes that can be caused by environmental factors, including diet, aging and even medications. These changes "affect the expression of genes without changing the actual DNA sequence," according to ACOG. Epigenetic changes can sometimes be inherited, reversed or prevented.
Genetic change is not always a bad thing. The gene variants called alleles, for instance, can be either normal or pathogenic. Normal variations include blood type and Rhesus factor. On the other hand, pathogenic variants or mutations can cause harmful changes to DNA sequencing, such as the variation responsible for sickle-cell anemia. Humans also experience small differences in their DNA called polymorphisms, which happen when more than one allele appears in the same place.
For example, all humans have the breast cancer type 1 (BRCA1) gene. But only some people have a variation or mutation in this gene. ACOG points out that genetic testing has found "more than 100 variations of the BRCA1 gene."
Breast and Ovarian Cancers
While BRCA1 variations may be benign or pathogenic, people with mutations to their BRCA1 or BRCA2 genes may be more likely to develop breast or ovarian cancers. However, these only account for about 10 percent of cases overall, according to Breastcancer.org. In fact, a type of polymorphism may account for more breast cancer than that found in people with BRCA1 or BRCA2 mutations.
Since BRCA genetic testing is becoming more widely available, OB/GYN patients may ask whether screening is available for any other cancer-related genes. The Centers for Disease Control and Prevention (CDC) states that although genetic testing is available for ovarian cancer, most women will not benefit from this testing.
Autoimmune Diseases and Multiple Sclerosis
Autoimmune diseases are largely thought to be polygenic (caused by multiple genes) and subject to environmental factors. But some autoimmune conditions are monogenic — monogenic lupus, for example, according to research from Frontiers in Immunology. A recent international effort led to the identification of new genetic markers for lupus. Interestingly, the genetic markers were seen in individuals with other autoimmune disorders. The study found that as the number of genetic variants increased, so did the risk of developing lupus. Since lupus is more common in reproductive-age women, this growing field of study is one for OB/GYNs to watch. Like lupus, osteoporosis can rarely have a monogenic cause, according to Frontiers in Endocrinology, but is usually caused by polygenic factors.
A study published in PLOS One found that, unlike lupus, multiple sclerosis (MS) is as much an environmental disease as it is a genetic disease. To develop MS, a person must not only carry the genetic combinations that make them susceptible to this disease but also have the right environmental triggers in a sufficient amount to cause MS to develop. Although women are more likely to be genetically susceptible to MS, they appear to require more environmental triggers than men to develop the disease. Therefore, it appears that genetic testing alone is not sufficient to determine the risk of developing MS.
Cardiovascular Disease
Research published in the journal Circulation: Genomic and Precision Medicine summarizes the current best practices for genetic testing for inherited cardiovascular diseases for the purposes of clinical management. Individuals undergoing in vitro fertilization may screen for inherited cardiovascular disease markers as a part of preimplantation genetic testing and only select and implant embryos that do not carry a harmful mutation.
Obesity
Although a gene influencing obesity has been identified, researchers have not identified a "clear inheritance pattern" related to genetic changes, according to the CDC. The CDC states that even among adults who were found to carry genetic variants that predisposed them to obesity, these adults could increase their physical activity to reduce their risk. Losing weight to stay within the recommended BMI range may also have a positive effect on fertility and IVF success.
The field of molecular genetics continues to uncover genetic causes of disease and explore how these factors interact with a person's environment to trigger a disease process. While modern gynecology calls for genetic testing for some conditions such as cancer, so that clinicians may help individuals plan for their future and tailor treatment options, testing for other diseases like MS and obesity may require caution. OB/GYNs need not become experts in genetics to serve their patients, but they should be prepared to answer basic questions about risk factors such as family history and ancestry and be able to identify the need for testing.
