9.3: Genes
In addition to our parents’ genes passing on inherited traits such as eye or hair color, we may also inherit unique health profiles. Genes can be associated with both protective health factors and disease risk factors. Some of these may not even be expressed physiologically until environmental forces - called epigenetics - change how the gene is expressed in the body. A few chronic conditions have a single, known, genetic link. Sickle-cell anemia and thalassemia are two such diseases, which are both caused by a mutation on chromosome 11. Interestingly enough, the same mutation that causes sickle-cell anemia may also have a protective effect against malaria infection (Contributors to Wikimedia projects, 2024). Many chronic diseases are thought to have genetic links, from mental illness to cancers or high cholesterol - whether a single gene or multiple genes are involved. For example, the BRCA1 and BRCA2 genes are linked to a high risk of reproductive cancers and breast cancer. In rare cases, obesity can be linked to the variation of a specific gene, called monogenic obesity. More commonly though, obesity, cancers, and other chronic diseases that run in families are a combination of multiple factors; including genetics, biology, environment, and behaviors (CDC, 2018).