There are some diseases that are genetically linked such as familial hyperlipidemia (inherited disorder that causes high cholesterol and high levels of triglycerides in the blood), and this cannot be changed unless genetic engineering were to happen. In the absence of the latter, it is important to gain knowledge of your condition so that you can make appropriate choices to improve your prognosis and quality of life.
Genetics can also influence how macronutrients (they’re the three categories of nutrients you eat the most and provide you with most of your energy: protein, carbohydrates and fats) are metabolized and/or how micronutrients are metabolised. This can help you if you know what drives the specific gene expressions that you have. If you know that saturated fats are not well metabolised in your body and that you have a sensitivity to carbohydrates, then modifying your diet accordingly will not only expedite a more favourable outcome, but you will also feel better. DNA testing is still in its infancy and new research literally comes to light on a daily basis. It is important to always investigate all the options so that when you make choices they come from the power of knowledge.