Is hypertrophic cardiomyopathy related to genetic factors and what are its inheritance patterns? Hypertrophic cardiomyopathy is closely related to heredity. It is the most common type of hereditary disease, and half or even up to 70% of hypertrophic cardiomyopathies run in families. The most common form of inheritance of hypertrophic cardiomyopathy is autosomal dominant, which means that there is a 50% chance that either parent will pass the disease on to their offspring if they have the disease. What tests are usually done in patients with hypertrophic cardiomyopathy? The diagnosis and tests for hypertrophic cardiomyopathy are complex. First, an electrocardiogram and cardiac ultrasound are performed for initial screening, and second, an MRI of the heart can help further confirm the diagnosis. Of course, for some special cases, 24-hour ambulatory ECG and exercise-induced cardiac ultrasound can provide further insight into the disease. Blood and urine and biochemical tests are not very helpful in confirming the diagnosis, but they can help us rule out other diseases.
However, even with all these tests, hypertrophic cardiomyopathy is still very difficult to differentiate from some diseases, such as hypertension-induced hypertrophy, aortic stenosis, and angina pectoris in coronary heart disease. In this case, we have to rely on the genetic testing technology developed in recent years, because hypertrophic cardiomyopathy is a disease closely related to genetic mutations, which can be 100% diagnosed through genetic testing, and genetic testing is also a routine test in Europe and the United States. The genetic testing technology of Fu Wai Hospital team is already mature enough to be used for the diagnosis of hypertrophic cardiomyopathy. There are many genetic sequencing companies in the market now, can we use them to complete the genetic testing of patients? Genetic testing is very important for hypertrophic cardiomyopathy, mainly in two aspects: early diagnosis of cardiomyopathy and assessment of the risk of sudden death. If the disease is detected early through genetic testing, the life expectancy of the patient is no different from that of a normal person after active, effective and correct treatment. Therefore, the key issue of hypertrophic cardiomyopathy is early diagnosis and early treatment.
However, the real clinical application of genetic testing is not just sequencing, it requires comprehensive data from clinical, genetics, gene sequencing and bioinformatics analysis, and detailed interpretation by a team of clinical experts and genetics experts, in order to truly achieve clinical diagnosis, otherwise many results and contents obtained from sequencing are of no value in clinical application. Therefore, the genetic company can complete the sequencing, but the interpretation and diagnosis need to be done by the hospital’s expert team. How should we diagnose, prevent and treat sudden death caused by hypertrophic cardiomyopathy? Sudden death is another very serious clinical consequence of hypertrophic cardiomyopathy. The medical history of sudden death, family history, whether the patient has recurrent syncope (loss of consciousness), the degree of myocardial hypertrophy, the degree of myocardial obstruction, and whether there is a combination of malignant arrhythmia, all of these indicators suggest the possibility of sudden death. The risk of sudden death should be evaluated by a specialist as soon as possible to take effective preventive or therapeutic measures. In recent years, genetic mutation type has been clearly defined by guidelines as an independent predictor of sudden death, which also suggests the importance of genetic testing in patients with hypertrophic cardiomyopathy. Can we use prenatal testing to determine whether the next generation carries the disease-causing gene? Is it possible to perform IVF to prevent the transmission of the disease gene to the next generation? There are two main concerns for patients, one is the diagnosis and treatment of the patient itself, and the second is that because this is a genetic disease, patients are more worried about the next generation. One way to find out if a child is hereditary is through prenatal diagnosis by amniocentesis, but this test carries a 1% risk of miscarriage; the other way is through IVF for genetic blockage. IVF is a more advanced method of genetic blockage, and we recommend it because it is a very painful process for a mother to make a choice after she conceives a child. However, there is an important prerequisite for this kind of blockage, that is, the father and mother themselves, as patients, must first undergo genetic testing to determine whether there is a disease-causing gene mutation and what kind of gene mutation it is. Once the patient has the desire to have the next generation, he or she must work with a professional team to perform effective genetic blocking.
At present, our team at Fu Wai Hospital has been working closely with the Reproduction Center of Beihang Hospital to carry out IVF programs for genetic blockage, so if you have requests or questions in this area, please feel free to come to my clinic.
This article is authorized by Dr. Lei Song.