Abstract
Cardiomyopathies are generally defined as myocardial disorders in which the heart muscle is structurally and functionally abnormal, in the absence of coronary artery disease, hypertension, valvular disease and congenital heart disease sufficient to cause the observed myocardial abnormality. According to the morphological and functional phenotype the diagnosis of hypertrophic and dilated cardiomyopathy can be established.
Hypertrophic cardiomyopathy (HCM) is an autosomal dominant cardiac disorder with a prevalence of 0.2% in the general population. More than 70% of HCM cases are familial.
Hypertrophic cardiomyopathy represents one of the the most frequent causes of sudden cardiac death in the young, especially in competitive athletes and a major cause of morbidity and mortality in the elderly. Dilated cardiomyopathy (DCM) is an inherited or acquired disease characterized by left ventricular dilatation and reduced systolic function.
DCM represents the third most common cause of heart failure and the most frequent cause of heart transplantation. It accounts for approximately 3% of all sudden cardiac deaths in young athletes.
Recently, more than 630 mutations in 16 different genes have been reported to cause cardiomyopathies. Of these mutations, HCM has been associated with 550 and DCM with more then 52 mutations.
In the vast majority of cases these genes encode for sarcomeric contractile proteins: Beta-myosin heavy chain (MYH7), myosin binding protein C (MYBPC3), troponin T (TNNT2), troponin I (TNNI3), cardiac alpha-actin (ACTC) and alpha-tropomyosin (TPM1). Nearly all of the mutations (86%) are single nucleotide mutations, which can lead to the changes in protein chains.
Remaining mutations include small in-frame insertions or deletions and rarely large deletions. The aim of the study was to analyze both MYH7 and TNNT2 exons in the patients with HCM and DCM diagnosis to improve the diagnostic and genetic consultancy in affected families.