Progress in understanding of human genome enables the researches to reveal genetic basis of many disorders, including genetic heart diseases--defects developed by genetic disorders. The most frequent causes of genetic diseases are defects of many genes (e.g., a correlation has been observed between arterial hypertension and mutations in ACE and ADD1 genes). Moreover, a defect of single gene can be connected with several disorders (e.g., mutations in preseniline genes observed in Alzheimer disease and dilated cardiomyopathy). On the other hand, mutations in genes coding elements of particular signaling pathway can cause similar disorders (mutations in different components of RAS-MAPK pathway cause such disorders as Noonan syndrome, LEOPARD syndrome, Costello syndrome and CFC). The ability to identify genetic markers connected with heart diseases may contribute to the improvement of diagnostic and treatment of such disorders.