Heart diseases are passed down through generations, affect people of all ages, and can be life-threatening. These heart diseases are genetically heterogeneous and have different clinical manifestations. Single-gene pathogenic variants may be associated with different heart diseases (clinical heterogeneity). Similar cardiac phenotypes may occur in different genes (genetic heterogeneity). Depending on the aetiology, the phenotype can be inherited in an autosomal dominant, autosomal recessive, or X-linked manner. Cardiomyopathy can also be inherited in mitochondria. Many common heart diseases have a strong genetic component. Some cardiovascular diseases are hereditary and can be identified through genetic testing. Combining the work of a child and adult cardiologist.